Trivalent doped cerium oxide compositions for biological contaminant removal - Patents.com

Abstract

Particulate oxide compositions comprising cerium oxide, a trivalent dopant, and any additional metal oxide other than cerium oxide and the trivalent dopant are useful in aiding in the removal of biological contaminants such as bacteria, viruses, fungi, protozoa (e.g., amoebas), yeast, and algae. The particulate oxide compositions comprise more cerium oxide than the trivalent dopant and have a unique depth profile in which the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is greater than the average ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. These trivalent doped cerium oxide compositions can be used to remove these biological contaminants from fluids including air and water, as well as from solid surfaces. Methods of using compositions containing these trivalent doped cerium oxide compositions to remove biological contaminants are also described.

Description

[Technical field]

[0001] Related Applications This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 236,949, filed August 25, 2021, the contents of which are incorporated herein by reference in their entirety. The present disclosure relates to novel trivalent doped cerium oxide (CeO2) particulate compositions and the use of trivalent doped cerium oxide (CeO2) compositions for biological contaminant removal. These compositions can be used as antimicrobial / antibacterial / antiviral agents. Thus, these compositions have application for removing bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds), algae, yeasts, and the like. In particular, these compositions can be used in methods for contact treatment of fluids, including liquids or air, and solid surfaces.

[0002] Introduction This disclosure generally relates to particulate oxide compositions including trivalent doped CeO2, and the use of trivalent doped cerium oxide (CeO2) compositions for the contact removal of bacteria, viruses, and other microbial contaminants. Thus, compositions containing these trivalent doped CeO2 species can remove biological contaminants from air and aqueous liquid streams, and in particular can remove bacteria and viruses from air and water, whether the microorganisms are at high or very low concentrations. These novel trivalent doped cerium oxide particulate compositions have unique physical / structural and electrochemical properties that make them useful for these important purposes. [Background technology]

[0003] Various techniques have been used to remove biological contaminants from air and aqueous systems. Examples of such techniques include adsorption onto high surface area materials such as alumina, filters with pore sizes smaller than the biological contaminants, and the use of highly oxidizing materials such as chlorine and bromine. Certain metals have also found use because they exhibit an oligodynamic effect, which is the biocidal effect of the metal. Metals known to exhibit an oligodynamic effect are Al, Sb, As, Ba, Si, B, Cu, Au, Pb, Hg, Ni, Ag, Th, Sn, and Zn. Incorporating these into technologies for air or aqueous system treatment remains a challenge because toxicity to human and animal life and costs are of major concern.

[0004] There remains a need for effective and inexpensive antimicrobial materials for removing bacteria, viruses and other microbial contaminants from fluids, including air, water, and other aqueous systems. Summary of the Invention

[0005] The present disclosure relates generally to novel trivalent doped cerium oxide compositions and the use of those compositions to remove biological contaminants.

[0006] Trivalent doped cerium oxide compositions are described herein as particulate oxide compositions comprising cerium oxide, a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf) and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein the average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition.

[0007] In certain embodiments, the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is about 10% to about 250% greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition. In other embodiments, the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is about 15% to about 250% greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition.

[0008] In certain embodiments of these particulate oxide compositions, the particulate oxide comprises cerium oxide in an amount of about 99.9% to about 20% by weight, based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 0.1% to about 50% by weight, based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 70% to about 0% by weight, based on the total weight of the particulate oxide composition.

[0009] In other embodiments of these particulate oxide compositions, the particulate oxide comprises cerium oxide in an amount of about 99.9% to about 50% by weight, based on the total weight of the particulate oxide composition; and a trivalent dopant in an amount of about 0.1% to about 50% by weight, based on the total weight of the particulate oxide composition.

[0010] The particulate oxide compositions have biological contaminant removal properties and therefore have application for removing bacteria or viruses from fluids, including air and water, and / or surfaces. The biological contaminants to be removed include bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds or fungi), and the like.

[0011] Also disclosed herein is a support composition comprising a support material and a particulate oxide composition. The support composition has biological contaminant removal properties and thus has application for removing bacteria or viruses from fluids including air and water, and / or surfaces. Biological contaminants to be removed include bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds or fungi), and the like.

[0012] The support compositions for removing biological contaminants disclosed herein include a support material comprising an organic polymer, cotton, glass fiber, or mixtures thereof, and a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the average ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition. In these support compositions, the particulate oxide composition is deposited on or in the support material.

[0013] In certain embodiments, these support compositions comprise from about 0.5 to about 80 weight percent of the particulate oxide composition, based on the total weight of the support composition.

[0014] The support composition, which comprises the support material and the particulate oxide composition, can be in a rigid or elastic form, and the support composition can be made into an article for removing biological contaminants, such as a filter, a fixed bed filter system, a plastic or glass bottle or container, a plastic or glass touch surface, and the like.

[0015] In one embodiment, a plastic article is disclosed. The plastic article is made of (i) an organic polymer selected from the group consisting of polyethylene, polyvinyl chloride, nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof; and (ii) a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally, a trivalent dopant selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof. The present invention also includes a support composition for removing biological contaminants comprising a particulate oxide composition comprising an additional metal oxide selected from the group consisting of cerium oxide and cerium oxide, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition, the particulate oxide composition is deposited on or in an organic polymer, and the plastic article comprises about 50 to about 100 weight percent of the support composition for removing biological contaminants based on the total weight of the plastic article. The plastic article may be a filter, a fixed bed filter system, a plastic bottle or container, a plastic touch surface, a plastic doorknob or handle cover, a plastic elevator button cover, and the like.

[0016] The particulate oxide compositions themselves, the support compositions, and the articles can be used in methods for removing biological contaminants, including bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds or fungi), and the like.

[0017] In one embodiment, a method for removing biological contaminants includes: (i) providing a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than a ratio of the trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; (ii) contacting the particulate composition with a biological contaminant selected from the group consisting of bacteria, viruses, fungi, protozoa (e.g., amoebas), and mixtures thereof; and (iii) removing at least about 90% of the biological contaminant by contact with the composition. In some embodiments, the particulate oxide composition is contained within a filter material or plastic.

[0018] In certain embodiments, the method treats an aqueous stream and the biological contaminant is in the aqueous stream. In other embodiments, the method treats a gaseous stream and the biological contaminant is in the gaseous stream. In still other embodiments, the contacting is by touching the solid to the composition, thus treating a solid surface by touching. In some of these embodiments, the contacting is by touching the solid to an article comprising the particulate oxide composition.

[0019] In certain embodiments treating gaseous or aqueous streams, the method may further include setting a target concentration of a biological contaminant. In these embodiments, a biological contaminant may be identified and a target concentration of the biological contaminant may be set. The method may further include monitoring the treated stream for biological contaminants.

[0020] In certain embodiments, the methods are for removing biological contaminants from a fluid or are methods for treating a fluid, in which the fluid may be a gaseous stream or an aqueous stream. In these embodiments, the method includes: (i) providing a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than a ratio of the trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; (ii) contacting a fluid containing a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof, with the particulate oxide composition; and (iii) removing the biological contaminant from the fluid by contact with the particulate oxide composition. Biological contaminants may be removed in amounts of 90% or greater.If the fluid is a liquid, the particulate oxide composition may be used by itself or the method may further include filtering the fluid / liquid.

[0021] In certain embodiments, the methods are for removing biological contaminants from a fluid or for treating a fluid. In these embodiments, the fluid may be a gaseous stream or an aqueous stream. In these embodiments, the method comprises: (i) a particulate oxide composition comprising: (a) a support material comprising an organic polymer, cotton, glass fiber, or mixtures thereof; and (b) a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is in an amount greater than the trivalent dopant. and a particulate oxide composition, wherein an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; (ii) contacting a fluid containing a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof, with the support composition; and (iii) removing the biological contaminant from the fluid by contact with the support composition. The biological contaminant may be removed in an amount of 90% or more.

[0022] In another embodiment for removing biological contaminants from a fluid (e.g., a gaseous or aqueous stream), the method includes (i) providing a particulate oxide composition comprising (a) a support material comprising an organic polymer, cotton, glass fiber, or mixtures thereof; and (b) a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is the trivalent dopant. and a particulate oxide composition, wherein the trivalent dopant to Ce is present in an amount greater than the trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition and the average ratio of trivalent dopant to Ce is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; (ii) contacting a gaseous or aqueous stream containing a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof, with the support composition; and (iii) removing the biological contaminant from the gaseous or aqueous stream by contact with the support composition. The biological contaminant may be removed in an amount of 90% or more. These methods may further include monitoring the biological contaminant after contacting. The monitoring may be by sampling or may be continuous.

[0023] These methods of treating fluids or gaseous or aqueous streams may further include the step of setting a target concentration of a biological contaminant. In these methods, a biological contaminant of interest is identified and then a target concentration of that biological contaminant is set. The method may further include the step of monitoring the biological contaminant in the treated stream. The monitoring step may be by sampling or may be continuous.

[0024] In methods for treating an aqueous stream, the particulate oxide composition may be used by itself by slurrying it with the aqueous stream. These methods involving slurrying may further include a filtering step.

[0025] In certain embodiments, the method includes: (i) providing a particulate oxide composition comprising: (a) a support material comprising an organic polymer, cotton, glass fiber, or mixtures thereof; and (b) a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the ratio of the trivalent dopant to C at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is about 0.01 to about 3.5 nm from the surface of the particulate oxide composition. and a particulate oxide composition, wherein the average ratio of e is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition; (ii) setting a target concentration of the biological contaminant; (iii) contacting a gaseous or aqueous stream containing the biological contaminant with the support composition and removing the biological contaminant by contact with the support composition to provide a treatment stream; and (iv) monitoring the treatment stream for a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. The target concentration can be set at a certain amount of contaminant (e.g., viruses, bacteria, protozoa / amoebas, or fungi) or can be set at a detection limit. [Brief description of the drawings]

[0026] [Figure 1] 1 is an SEM image of the composition of Example 1 with a scale bar of 200 nm.

[0027] [Diagram 2] 1 is an SEM image of the composition of Example 1 with a scale bar of 2 μm.

[0028] [Diagram 3] TEM images of the composition of Example 1 with a scale bar of 10 nm. A light field image is on the left and a dark field image is on the right.

[0029] [Figure 4] TEM images of the composition of Example 1 with a scale bar of 20 nm. A light field image is on the left and a dark field image is on the right.

[0030] [Figure 5A] 1 is a diagram showing the temperature programmed desorption of CO2 from the composition of Example 1.

[0031] [Figure 5B] Temperature programmed desorption of CO2 from the composition of Example 2.

[0032] [Figure 5C] 13 is a graph showing the temperature programmed desorption of CO2 from the composition of Example 3.

[0033] [Figure 6] 4 is a graph showing the temperature programmed desorption of H2 for the compositions of Examples 1, 2, and 3.

[0034] [Figure 7] 1 is a graph of zeta potential versus pH for the compositions of Examples 1, 2, and 3.

[0035] [Figure 8] 1 is a graph showing the ratio of LaO+ / CeO+ versus depth for the composition of Example 1 and the composition of Example 2.

[0036] [Figure 9] 1 is a graph showing the ratio of PrO+ / CeO+ versus depth for the compositions of Examples 4 and 5.

[0037] [Figure 10]1 is an SEM image of the composition of Example 2 with a scale bar of 200 nm.

[0038] [Figure 11] 1 is an SEM image of the composition of Example 2 with a scale bar of 20 nm.

[0039] [Figure 12A] FIG. 11B is a light field TEM image of the composition of Example 2 with a scale bar of 200 nm. The box indicates the zoomed area of ​​FIG.

[0040] [Figure 12B] FIG. 11C is a light field TEM image of the composition of Example 2 with a scale bar of 20 nm. The box indicates the zoomed area of ​​FIG.

[0041] [Figure 12C] 1 is a light field TEM image of the composition of Example 2 with a scale bar of 5 nm.

[0042] [Figure 12D] 1 is a dark field TEM image of the composition of Example 2 with a scale bar of 5 nm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Before the compositions, articles, and methods are disclosed and described, it is to be understood that the disclosure is not limited to the specific structures, process steps, or materials disclosed herein, but extends to equivalents thereof as recognized by one of ordinary skill in the art. It is also to be understood that the terms used herein are used only for the purpose of describing particular embodiments, and are not intended to be limiting. It is noted that as used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to a "trivalent dopant" should not be construed as limiting a quantity or source, a reference to a "step" may include multiple steps, and a reference to the "product" or "product" of a reaction or process should not be construed as all of the products of the reaction / process, and a reference to a "process" may include a reference to one or more of such process steps. Thus, a processing step may include multiple or repeated processing of similar materials / streams to produce a specified process product.

[0044] The singular forms of biological contaminants also include plural referents. For example, "amoeba" and "virus" include references to "amoebae" and "viruses," respectively.

[0045] Numerical values ​​with "about" or "approximately" include typical experimental variance. As used herein, the terms "about" and "approximately" are used interchangeably and mean within a statistically significant range of values ​​such as a stated weight percentage, surface area, concentration range, time frame, distance, molecular weight, temperature, or pH. Such ranges may be within an order of magnitude, typically within 10%, and even more typically within 5% of the indicated value or range. Sometimes such ranges may be within the experimental error typical of the standard method used to measure and / or determine a given value or range. The allowable variation encompassed by the term "about" depends on the particular system under study and can be readily understood by one of ordinary skill in the art. Whenever a range is recited within this application, at least all integers within that range are contemplated as embodiments of the invention.

[0046] The present disclosure relates to trivalent doped CeO2 particulate compositions having activity in removing biological contaminants, and their use for removing biological contaminants. The trivalent doped CeO2 particulate compositions are mainly mixed oxides of Ce and trivalent dopants. In certain embodiments, the trivalent doped CeO2 particulate compositions contain an amount of additional metal oxides. The trivalent doped CeO2 particulate compositions disclosed herein can be used as slurries or in support compositions and / or articles intended to remove biological contaminants, as well as in methods for removing biological contaminants. These biological contaminants include bacteria, viruses, fungi, protozoa (e.g., amoebas), yeasts, and mixtures thereof.

[0047] These trivalent doped CeO2 compositions are described herein as particulate oxide compositions. Thus, the disclosed particulate oxide compositions include cerium oxide and one or more trivalent dopants. The particulate oxide compositions may optionally include additional metal oxides other than cerium oxide and trivalent dopants, and / or trace amounts of impurities. In certain embodiments, the particulate oxide compositions contain about 0 additional metal oxides. The particulate oxide compositions disclosed herein exhibit activity in removing / reducing biological contaminants.

[0048] The cerium of the cerium oxide in the particulate oxide composition is Ce(IV). The trivalent rare earth dopant may be selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), cerium (Ce), and mixtures thereof. In certain embodiments, the trivalent dopant is yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof, and in certain embodiments, the trivalent dopant is Nd, La, or mixtures thereof. In other embodiments, the trivalent dopant is La. In further embodiments, the trivalent dopant is Pr. As described, the trivalent dopant is present in the particulate composition as an oxide such that the particulate oxide composition comprises a mixed oxide of at least cerium and the trivalent dopant. The trivalent dopant is present in an insignificant amount compared to the cerium oxide, and thus the particulate oxide composition contains more cerium oxide than the trivalent dopant.

[0049] The particulate oxide composition may optionally contain additional metal oxides other than cerium oxide and the trivalent dopant. These additional metal oxides may be selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof.

[0050] Thus, the disclosed particulate oxide compositions are mixed oxide compositions (i.e., a mixture of oxides of at least cerium and a trivalent dopant). The composition is also identified herein as a trivalent doped cerium oxide, and when so identified, it is a mixed cerium-lanthanum oxide, although this description does not exclude additional metal oxides, unless the composition is identified as containing about zero additional metal oxides other than cerium and the trivalent dopant.

[0051] In certain embodiments of the particulate oxide composition, the trivalent dopant is La and the particulate oxide composition contains about 0 additional metal oxides. In these embodiments, the particulate oxide composition is a mixed cerium-lanthanum oxide (or La-doped cerium oxide).

[0052] The particulate oxide composition disclosed herein includes a trivalent dopant in an amount of about 0.1% to about 50% by weight based on the total weight of the particulate oxide composition. As discussed above, the trivalent dopant is present in a minor amount compared to the cerium oxide. In certain embodiments, the particulate oxide composition includes a trivalent dopant in an amount of about 0.5% to about 40% by weight based on the total weight of the particulate oxide composition, or in an amount of about 1% to about 40% by weight based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition includes a trivalent dopant in an amount of about 2% to about 35% by weight based on the total weight of the particulate oxide composition, or in an amount of about 2% to about 30% by weight based on the total weight of the particulate oxide composition. In further embodiments, the particulate oxide composition includes a trivalent dopant in an amount of about 2% to about 25% by weight based on the total weight of the particulate oxide composition, or in an amount of about 5% to about 20% by weight based on the total weight of the particulate oxide composition. In certain of these embodiments, the particulate oxide composition includes a trivalent dopant in an amount of about 15% by weight based on the total weight of the particulate oxide composition. In certain of any of the above embodiments, the trivalent dopant is lanthanum and the particulate oxide composition is lanthanum-doped cerium oxide (ie, a mixed oxide of cerium and lanthanum).

[0053] In embodiments where the particulate oxide composition contains cerium oxide, one or more trivalent dopants, and about zero additional metal oxide, the amount of cerium oxide corresponds to and varies with the amount of the trivalent dopant such that the total amount of the trivalent dopant and cerium oxide is about 100% of the particulate composition. In certain of these embodiments containing about zero additional metal oxide, the trivalent dopant is lanthanum and the particulate oxide composition is lanthanum doped cerium oxide.

[0054] In the particulate oxide composition, the cerium oxide is present in an amount greater than the trivalent dopant. The particulate oxide compositions disclosed herein generally include cerium oxide in an amount of about 99.9% to about 20% by weight based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition contains cerium oxide in an amount of about 99.5% to about 25% by weight, or about 99% to about 30% by weight, based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition contains cerium oxide in an amount of about 98% to about 65% by weight, or about 98% to about 70% by weight, based on the total weight of the particulate oxide composition. In further embodiments, the particulate oxide composition contains cerium oxide in an amount of about 98% to about 75% by weight, or about 95% to about 80% by weight, based on the total weight of the particulate oxide composition. In certain of these embodiments, the particulate oxide composition contains cerium oxide in an amount of about 85% by weight based on the total weight of the particulate oxide composition, the amount of cerium oxide varying with and corresponding to the amount of trivalent dopant and any amount of additional metal oxide such that the total is about 100% of the particulate composition.

[0055] In certain embodiments, the particulate oxide composition includes about 0 wt.% additional metal oxide, and in these embodiments, the particulate oxide composition includes cerium oxide in an amount that provides about 100% of the particulate composition based on the weight % of the trivalent dopant. For example, in embodiments that contain a trivalent dopant in an amount of about 0.1 wt.% to about 50 wt.% based on the total weight of the particulate oxide composition, the composition contains cerium oxide in an amount of about 99.9 wt.% to about 50 wt.%. In embodiments that contain a trivalent dopant in an amount of about 1 wt.% to about 40 wt.% based on the total weight of the particulate oxide composition, the composition contains cerium oxide in an amount of about 99 wt.% to about 60 wt.%. In embodiments that contain a trivalent dopant in an amount of about 2 wt.% to about 30 wt.% based on the total weight of the particulate oxide composition, the composition contains cerium oxide in an amount of about 98 wt.% to about 70 wt.%, etc.

[0056] The particulate oxide composition may optionally contain additional metal oxides other than cerium oxide and trivalent dopants. These additional metal oxides may be selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof. The particulate oxide compositions disclosed herein generally include the additional metal oxide in an amount of from about 70% to about 0% by weight based on the total weight of the particulate oxide composition.

[0057] In certain embodiments, the particulate oxide comprises cerium oxide in an amount of about 99.9% to about 20% by weight based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 0.1% to about 50% by weight based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 70% to about 0% by weight based on the total weight of the particulate oxide composition. In the particulate oxide composition, the cerium oxide is present in an amount greater than the trivalent dopant.

[0058] When present, the particulate oxide composition generally includes the additional metal oxide in an amount of about 70% to about 0.1% by weight based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition includes the additional metal oxide in an amount of about 50% to about 0.1% by weight based on the total weight of the particulate oxide composition, or in an amount of about 30% to about 0.1% by weight based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition includes these additional metal oxides in an amount of about 10% to about 0.1% by weight based on the total weight of the particulate oxide composition. In certain embodiments, the particulate oxide composition includes about 0% by weight of the additional metal oxide. The amount of the additional metal oxide varies with and corresponds to the amount of the trivalent dopant and the amount of cerium oxide such that the total amount is about 100% of the particulate composition.

[0059] In one embodiment, the particulate oxide composition comprises a trivalent dopant in an amount of about 2% to about 25% by weight, cerium oxide in an amount of about 20% to about 30% by weight, and an additional metal oxide in an amount of about 45% to about 75% by weight, based on the total weight of the particulate oxide. In the particulate oxide composition, the cerium oxide is present in an amount greater than the trivalent dopant, and the amounts of the components are varied to provide a total of about 100% of the particulate composition.

[0060] In an alternative embodiment, the particulate oxide composition comprises a trivalent dopant in an amount of about 2% to about 25% by weight, cerium oxide in an amount of about 45% to about 75% by weight, and an additional metal oxide in an amount of about 20% to about 30% by weight, based on the total weight of the particulate oxide. In the particulate oxide composition, the cerium oxide is present in an amount greater than the trivalent dopant, and the amounts of the components are varied to correspond such that the total amounts are about 100% of the particulate composition.

[0061] The particulate oxide composition may optionally further include trace amounts of impurities. These impurities are typically present in amounts of about 1% by weight or less (up to about 0, or to undetectable amounts) based on the total weight of the particulate oxide composition. These impurities include residual solvents, salts, other metals, and the like. These other metals include those commonly found in water, such as magnesium, iron, calcium, silicon, sodium, and the like. Amounts of these impurities (from about 1% by weight to about 0, or to undetectable amounts) may be present in any of the above and below embodiments of the particulate oxide composition. If present and detectable, any impurity is generally present in an amount of about 100 ppm or less.

[0062] The novel trivalent doped cerium oxide particulate compositions produced by the methods described below possess unique structural (i.e., physical) and electrochemical properties which make them particularly useful for the important purpose of removing biological contaminants.

[0063] The novel particulate oxide compositions disclosed herein have a unique depth profile for the distribution of cerium oxide and trivalent dopant. This unique depth profile means that the ratio of trivalent dopant to Ce is higher closer to the surface of the particulate oxide composition compared to deeper within the particulate oxide composition. Without wishing to be bound by any theory, the unique depth profile of the particulate oxide composition may provide improved activity for removing biological contaminants.

[0064] Those skilled in the art recognize that these particulate oxide compositions have a surface, which is referred to as about 0 nm, and those skilled in the art know how to measure Ce and trivalent dopants from this surface (i.e., at 0 nm) to depths (measured in nm) within the particulate oxide composition, from which they can calculate the ratio of trivalent dopant to Ce at different depths and the average ratio of trivalent dopant to Ce.

[0065] The unique depth profile of the particulate oxide composition is characterized such that the average ratio of trivalent dopant to Ce from about 0 nm (i.e., the surface) to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition. Measurements of Ce and trivalent dopant are taken at specific intervals from 0 nm (i.e., the surface) to about 3.5 nm and then averaged. Measurements of Ce and trivalent dopant are also taken from about 15 nm from the surface of the particulate composition. FIG. 8 shows the LaO versus depth ratio. + / CeO + 4 is a graph of the ratio of SiO 2 to SiO 2 , illustrating this unique depth profile for an example particulate oxide composition.

[0066] The depth profile of the distribution of cerium oxide and trivalent dopants is measured by time-of-flight (ToF) secondary ion mass spectrometry (SIMS) depth profilometry as described in Noel, C. et al. ToF-SIMS Depth Profiling of Organic Delta Layers with Low-Energy Cesium Ions: Depth Resolution Assessment, Journal of The American Society for Mass Spectrometry, Vol. 30 (2019) pp 1537-1544, the entire contents of which are incorporated by reference. As will be understood by those skilled in the art, a square cross-section of a grain of sample material is selected and analyzed by ToF-SIMS, which analyzes at a depth of 0 nm (i.e., the surface). ToF-SIMS works by bombarding a target material with an ion beam, which causes sputtering of the material. Sputtering is the phenomenon in which tiny particles are ejected from the surface of a solid material. The ejected particles are then mass analyzed in a mass spectrometer. The ion source for ToF-SIMS analysis in this disclosure is a cesium ion source operating at 2 keV with a target current of 130 nA, with a sputtering size of 500 μm 2 The analysis area is 200 μm 2 , 2 frame analysis, followed by 6 frame sputtering, and 60 s sputtering time. The selected square cross section is then etched with an ion beam to remove surface atoms. In this disclosure, the primary ion beam is a bismuth liquid metal ion gun running at 30 keV with a pulsed target current of about 0.6 pA, and the sputter size is 250 μm. 2 and the analysis area is 100 μm 2, 2 frame analysis, followed by 50 frame sputtering, and 20,000 seconds sputtering time. The time of etching correlates with the depth of etching, so the depth can be controlled. In this disclosure, the sputtering depth was calibrated to 1 nm / s. The exposed surface is then reanalyzed by ToF-SIMS to obtain an analysis at the new depth. The particulate composition can be analyzed at any nm increment, for example, about 0.2 nm increments, about 0.5 nm increments, about 1 nm increments, etc. This process is repeated until the desired depth is obtained. The observed mass spectrometry data is then correlated with the depth at which it was collected. In this disclosure, it is important to determine the ratio of trivalent dopant to Ce, and therefore this is the data reported.

[0067] The novel particulate oxide composition disclosed herein comprises cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the average ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition. In one embodiment of this particulate oxide composition, the composition comprises from about 0.1 wt.% to about 50 wt.% of the trivalent dopant. In a particular embodiment, the composition further comprises from about 99.9 wt.% to about 50 wt.% of the cerium oxide based on the total weight of the particulate oxide composition.

[0068] Another embodiment disclosed herein is a particulate oxide composition comprising cerium oxide and a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and an average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the average ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition, and the composition comprises from about 2% to about 30% by weight of the trivalent dopant. In one embodiment of this particulate oxide composition, the composition comprises cerium oxide in an amount of from about 98% to about 70% by weight based on the total weight of the particulate oxide composition.

[0069] It can be understood that the particulate oxide compositions containing trivalent doped CeO2 disclosed herein having the described depth profiles can have any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxide.

[0070] In certain embodiments, the particulate oxide composition contains cerium oxide and a trivalent dopant, with trace to no (i.e., about 0) additional metal oxides, and only 1% to no (i.e., 0 or undetectable) impurities. If present and detectable, any impurities are generally present in amounts of about 100 ppm or less.

[0071] In a particular embodiment, the particulate oxide composition has an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition that is about 10% to about 250% greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition. In another embodiment, the particulate oxide composition has an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition that is about 15% to about 250% greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition. As described above, it is understood that 0 nm from the surface of the particulate oxide composition is the surface of the particulate oxide composition.

[0072] It can be understood that the particulate oxide compositions containing trivalent doped CeO2 disclosed herein having the depth profile described above can also have the above amounts of trivalent dopant, cerium oxide, and any additional metal oxides, as well as any of the additional properties described below.

[0073] The novel particulate oxide composition including trivalent doped CeO2 can also exhibit unique physical properties, including exhibiting both physisorption and chemisorption, for example, of CO2 (see Figures 5A, 5B, and 5C). Physisorption, also known as physical adsorption, is a weak association, for example via van der Waals. Chemisorption, also known as chemical adsorption. In chemical adsorption, adsorption occurs and the adsorbed material is bound by chemical bonds. This is a much stronger adsorption than physical adsorption. Exhibiting physisorption and chemisorption is a unique feature of the novel particulate composition including trivalent doped CeO2 with the depth profile described above. Since the adsorbent is CO2 (an acid), exhibiting chemisorption indicates that the material is more basic and may provide improved activity for removing biological contaminants. This property of exhibiting physisorption and chemisorption can be combined with any of the depth profiles described above, as well as any of the amounts of trivalent dopant, cerium oxide, and any additional metal oxide described above, as well as additional properties described below.

[0074] The novel particulate oxide compositions with unique depth profiles can also be more easily reduced than compositions produced by prior art methods, and therefore these novel compositions are more oxidizing. Figure 6 is a graph of temperature-programmed hydrogen reduction of materials from Examples 1, 2, and 3. Example 1 has a large sharp peak at low temperature. This peak indicates that the novel particulate oxide composition is more easily reduced compared to the compositions of Examples 2 or 3. Thus, the novel particulate oxide composition may be more oxidizing and therefore more effective at removing / reducing biological contaminants. The graph for Example 2 has essentially the same shape as Example 1, but is shifted to higher temperatures, indicating that the material requires more energy to react with hydrogen and is therefore less oxidizing than Example 1. The graph for Example 3, which is undoped cerium oxide, shows two peaks of broad, but not very high, hydrogen reduction. This indicates that there are two types of reduction that can occur with this material, with the higher temperature being much more difficult to achieve. Without wishing to be bound by any theory, it is believed that the unique depth profile of the novel particulate oxide composition, such that there is a higher ratio of trivalent dopant to Ce on and near the surface of the particulate material, may result in this change in hydrogen reduction temperature and increased oxidation properties. Furthermore, the increased oxidation properties of the novel particulate oxide composition with its unique depth profile may provide improved activity for removing biological contaminants. This property may also be combined with any of the depth profiles, physical properties, and any of the amounts of trivalent dopant, cerium oxide, and any additional metal oxides described above, as well as additional properties described below.

[0075] The novel particulate oxide compositions containing trivalent doped CeO2 and having the unique depth profile disclosed herein can further exhibit higher basicity as indicated by their isoelectric point and zeta potential (see FIG. 7). In certain embodiments, the particulate oxide compositions described herein have an isoelectric point at a pH of about 8 to about 9. In further embodiments, the particulate oxide compositions described herein have a zeta potential of about 20 to about 40 mV at a pH of about 7. Having a higher isoelectric point indicates that the material is more basic and may provide improved activity for removing biological contaminants. This property can also be combined with any of the depth profiles, physical properties, and any of the above amounts of trivalent dopant, cerium oxide, and any additional metal oxide, as well as additional properties described below.

[0076] The particulate oxide compositions including trivalent doped CeO2 disclosed herein can also have a surface area that assists in providing biological contaminant removal properties.

[0077] As described herein, surface area is the apparent surface area of ​​a composition determined by using a Micromeritics ASAP 2000 system and nitrogen at about 77 Kelvin. The procedure outlined in ASTM International Test Method D 3663-03 (Reapproved 2008) was used, with one notable exception. It is well known that "BET surface area" determinations are not possible for materials containing microporous structures. Recognizing that the surface area is an approximation, the reported value is labeled as an "apparent surface area" value rather than a "BET surface area" value. In accordance with commonly accepted procedures, the determination of apparent surface area, application of the BET equation, was limited to a pressure range where the term na(lP / Po) of the equation increases continuously with P / Po. The samples were degassed under nitrogen at about 300 degrees Celsius for about 2 hours.

[0078] The particulate oxide composition containing trivalent doped CeO2 disclosed herein has a concentration of about 70 μm. 2 / g~about 300m 2 / g. Without wishing to be bound by any theory, it is believed that surface area can affect and improve the removal of biological contaminants from gaseous or aqueous streams or by contact with solid surfaces.

[0079] It can be understood that a particulate oxide composition having this surface area, in combination with any one or more of the depth profile and other above-mentioned properties, and any of the above-mentioned amounts of trivalent dopant, cerium oxide, and optional additional metal oxide, can have an average pore volume as set forth below.

[0080] The particulate oxide composition typically has a particle size of about 0.01 cm 3 / g ~ approx. 1.5cm 3 / g of average (mean, median, and mode) pore volume (as determined by N2 adsorption). Without wishing to be bound by any theory, it is believed that the average pore volume can affect and improve the removal of biological contaminants from aqueous or gaseous streams.

[0081] It can be understood that the particulate oxide composition can have the above-mentioned average pore volume in combination with any one or more of the above-mentioned surface areas, depth profiles, and other above-mentioned properties, and any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxides.

[0082] Particulate oxide compositions containing cerium oxide and one or more trivalent dopants disclosed herein effectively remove biological contaminants. Trivalent-doped cerium oxide particulate compositions can remove approximately 90% or more of biological contaminants. In certain embodiments, trivalent-doped cerium oxide particulate compositions can remove approximately 99% or more of biological contaminants.

[0083] The particulate oxide composition can be slurried with a biological contaminant-containing aqueous stream to effectively remove the biological contaminants. In some embodiments, slurrying the particulate oxide composition with the biological contaminant-containing aqueous stream removes at least about 90% of the biological contaminants. In other embodiments, the slurrying removes at least 95%, or more preferably 99% or 99%+ of the biological contaminants.

[0084] The particulate oxide compositions described herein may also be incorporated into support compositions and / or articles for removing biological contaminants, as described below.

[0085] Support Compositions and Articles Also disclosed herein are support compositions comprising a support material and the trivalent doped CeO2 particulate composition described herein, for removing biological contaminants, as described herein, and comprising a support material and a trivalent doped cerium oxide particulate composition comprising cerium oxide doped with a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf) and mixtures thereof.

[0086] Thus, the support composition comprises a particulate oxide composition comprising a support material and cerium oxide, one or more trivalent dopants, and optionally additional metal oxides other than cerium oxide and the trivalent dopants, and / or trace amounts of impurities. In certain embodiments, the particulate oxide composition contains about 0 additional metal oxides. In certain embodiments, the particulate oxide composition has a unique depth profile, the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the average ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition. The particulate oxide composition in the support composition includes all of the particulate oxide composition embodiments described above.

[0087] The support composition for removing biological contaminants also includes a support material, which includes an organic polymer, cotton, fiberglass, or a mixture thereof.

[0088] The organic polymer may be a homopolymer or copolymer of organic monomers. The organic polymer may be a silicone or polysiloxane (i.e., a polymer composed of siloxanes (-R2Si-O-SiR2-, where R is an organic group). The organic polymer may also be a thermoset polymer, such as a thermoplastic elastomer. In certain embodiments, the organic polymer is selected from the group consisting of polyethylene, polycarbonate, polyvinyl chloride, nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, copolymers thereof, and mixtures thereof. In certain embodiments, the organic polymer is a silicone.

[0089] In the support compositions disclosed herein, the particulate oxide composition is deposited on or in a support material.

[0090] In one embodiment of the support composition, the particulate oxide composition comprises cerium oxide in an amount of about 99.9 wt.% to about 20 wt.%, based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 0.1 wt.% to about 50 wt.%, based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 70 wt.% to about 0 wt.%, based on the total weight of the particulate oxide composition.

[0091] In another embodiment of this supported composition, the particulate oxide composition comprises from about 0.1% to about 50% by weight of a trivalent dopant, and from about 99.9% to about 50% by weight of cerium oxide, based on the total weight of the particulate oxide composition.

[0092] In yet another embodiment of this supported composition, the particulate oxide composition comprises cerium oxide in an amount of about 20% to about 30% by weight, based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 2% to about 25% by weight, based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 45% to about 78% by weight, based on the total weight of the particulate oxide composition.

[0093] In a further embodiment of this supported composition, the particulate oxide composition comprises cerium oxide in an amount of about 45% to about 78% by weight, based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 2% to about 25% by weight, based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 20% to about 30% by weight, based on the total weight of the particulate oxide composition.

[0094] In these support compositions, it can be understood that the particulate oxide composition within the support composition can have any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxide.

[0095] These support compositions can include a support material including an organic polymer, cotton, glass fiber, or mixtures thereof, and the novel particulate oxide composition described above, which has a unique depth profile. As described, the particulate oxide composition is a mixed oxide composition (i.e., a mixture of oxides of cerium, trivalent dopants, and optionally additional metal oxides) and has unique structural (i.e., physical) and electrochemical properties. In these supported compositions, the particulate oxide composition comprises cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. In these supported compositions, the particulate oxide composition (i.e., the novel trivalent doped cerium oxide) is deposited on or in a support material. This novel particulate oxide composition includes all of the above-mentioned embodiments, including all of the properties and any of the above-mentioned amounts of the trivalent dopant, cerium oxide, and optional additional metal oxide.

[0096] In all embodiments, the support composition contains from about 0.5 to about 80 weight percent of the particulate oxide composition (i.e., trivalent doped cerium oxide) based on the total weight of the support composition. In certain embodiments, the composition contains from about 0.5 to about 50 weight percent of the particulate oxide composition based on the total weight of the support composition. In other embodiments, the composition contains from about 0.5 to about 25 weight percent of the particulate oxide composition based on the total weight of the support composition. In still other embodiments, the composition contains from about 0.5 to about 10 weight percent of the particulate oxide composition based on the total weight of the support composition. In further embodiments, the composition contains from about 0.5 to about 5 weight percent of the particulate oxide composition based on the total weight of the support composition.

[0097] The support composition, which includes a support material and a particulate oxide composition (i.e., trivalent doped cerium oxide), can be in a rigid or elastic form. The support composition can form an article for removing biological contaminants, such as a filter or a plastic container. The article can be in a rigid or elastic form.

[0098] When the support composition forms an article, the article contains from about 50 to about 100 weight percent of the support composition comprising the support material and the particulate oxide composition, based on the total weight of the article. In certain embodiments, the article contains from about 75 to about 95 weight percent of the support composition comprising the support material and the particulate oxide composition, based on the total weight of the article.

[0099] When the particulate oxide composition and support are formed into a resilient or rigid article, the article may also include binders, sand, gravel, glass wool, metal or plastic containers, and the like.

[0100] In some embodiments, the support material may be an organic polymer. In certain of these embodiments, the trivalent dopant is Pr, La, or a mixture thereof. When this composition using an organic polymer as the support material forms an article, the article may be a plastic article. In these embodiments, the organic polymer may be selected from the group consisting of polyethylene, polyvinyl chloride (PVC), nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof. In certain embodiments, the organic polymer is polyethylene, polycarbonate, or a mixture thereof. If plastic, the article may be in the form of a filter, a bottle, a container, or a plastic cover for a high-touch service. The filter may be a fixed bed. The bottle or container may be for liquids. High-touch surfaces include escalator or staircase handrail covers, elevator button covers, doors, door handles or knobs or covers therefor, public transportation covers, touch pads for electronic transactions, and the like.

[0101] In some embodiments, the support material may be cotton. In certain of these embodiments, the trivalent dopant is Pr, La, or a mixture thereof. When this support composition using cotton as the support material forms an article, the article may be a filter or a fabric.

[0102] In some embodiments, the support material may be glass fiber. In certain of these embodiments, the trivalent dopant is Pr, La, or a mixture thereof. When this support composition using glass fiber as the support material forms an article, the article may be a filter, a bottle, a container, or a high-frequency touch surface. The filter may be a fixed bed. High-frequency touch surfaces include elevator button covers, doors, public transportation covers, touch pads for electronic transactions, etc.

[0103] In certain embodiments, the support material may be cotton and an organic polymer. In certain of these embodiments, the organic polymer may be selected from the group consisting of nylon, polyester, polyamide, and mixtures thereof. In certain of these embodiments, the trivalent dopant is Pr, La, or mixtures thereof. When this mixture as the support material forms an article, the article may be a filter or a fabric.

[0104] In certain embodiments, the support material may be glass fiber and an organic polymer. The organic polymer may be selected from the group consisting of polyethylene, polyvinyl chloride (PVC), nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof. In certain of these embodiments, the organic polymer may be selected from the group consisting of polyethylene, polycarbonate, and mixtures thereof. In certain of these embodiments, the trivalent dopant is Pr, La, or mixtures thereof. When this mixture as the support material forms an article, the article may be a filter, a bottle, a container, or a high-frequency touch surface. The filter may be a fixed bed. High-frequency touch surfaces include escalator or staircase handrail covers, elevator button covers, door, door handle or knob covers, public transportation covers, touch pads for electronic transactions, and the like.

[0105] In some embodiments, the support material may be polyethylene or polycarbonate. In certain of these embodiments, the trivalent dopant is Pr, La, or a mixture thereof. When the support composition forms an article, the article may be a plastic article and may be in the form of a filter, a bottle, a container, or a plastic cover for a high-frequency touch surface. The filter may be a fixed bed.

[0106] In certain embodiments, the support material can be silicone. In certain of these embodiments, the trivalent dopant is Pr, La, or a mixture thereof.

[0107] In certain embodiments, the article is a plastic article. The plastic article may be in the form of a filter, a bottle, a container, or a plastic cover for a high-frequency touch surface. The plastic article comprises a support composition for removing biological contaminants, comprising (i) an organic polymer selected from the group consisting of polyethylene, polyvinyl chloride, nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof. The plastic article further comprises (ii) a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof. In certain of these embodiments, the trivalent dopant is Pr, La, or mixtures thereof. Furthermore, in certain of these embodiments of the plastic article, the organic polymer may be selected from the group consisting of polyethylene, polycarbonate, and mixtures thereof.

[0108] In certain embodiments of the plastic article, it comprises (ii) a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and the average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. In certain of these embodiments of the plastic article, the organic polymer may be selected from the group consisting of polyethylene, polycarbonate, and mixtures thereof.

[0109] In all embodiments of the plastic article, the particulate oxide composition is deposited on or in an organic polymer, In certain embodiments, the plastic article comprises about 50 to about 100 weight percent of the support composition for removing biological contaminants, based on the total weight of the plastic article.

[0110] In a particular embodiment of the plastic article, it comprises a particulate oxide composition comprising about 0.1% to about 50% by weight of a trivalent dopant, and about 99.9% to about 50% by weight of cerium oxide, based on the total weight of the particulate oxide composition. This particular particulate oxide composition includes all of the particulate oxide composition embodiments described above.

[0111] The novel trivalent doped cerium oxide particulate compositions, support compositions, and articles disclosed herein having unique depth profiles can remove greater than about 90% of biological contaminants. In certain embodiments, the novel trivalent doped cerium oxide particulate compositions, support compositions, and articles disclosed herein having unique depth profiles can remove greater than about 99% of biological contaminants.

[0112] Biological contaminants removed by the articles, support compositions, particulate oxide compositions, and methods disclosed herein include viruses, bacteria, fungi (e.g., molds or fungi), protozoa (e.g., amoebas), algae, yeasts, and the like, and mixtures thereof. In certain embodiments, the biological contaminants removed by the articles, compositions, and methods disclosed herein are selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. In certain embodiments, the biological contaminants removed by the articles, compositions, and methods disclosed herein are bacteria, viruses, amoebas, and mixtures thereof. In other embodiments, the biological contaminants are bacteria, viruses, and mixtures thereof.

[0113] In certain embodiments, biological contaminants removed include substances of concern in aqueous streams, such as wastewater, and airborne substances of concern.

[0114] Bacteria include gram-positive and gram-negative bacteria. Bacteria include those commonly found in water, including fecal coliforms. Bacteria include, for example, Streptococcus, Staphylococcus, Escherichia coli, Methicillin-resistant Staphylococcus aureus (MRSA), Legionella pneumophila, Campylobacter Jejuni, Salmonella, Mycobacterium tuberculosis, Corynebacterium diphtheriae, Listeria monocytogenes, Bordetella pertussis, and the like. Viruses include, for example, rhinoviruses, coronaviruses, vaccinia, polioviruses, varicella zoster viruses, paramyxoviruses, influenza viruses, morbilliviruses, hepatitis A viruses (HAV), adenoviruses (HAdV), rotaviruses (RoV), sapoviruses, respiratory syncytial viruses (RSV), paramyxoviruses, varicella zoster viruses (VZV), smallpox viruses (including smallpox and monkeypox), and other enteric viruses such as noroviruses (NoV), coxsackie viruses, echoviruses, reoviruses, and astroviruses. Other microbial contaminants include protozoa (e.g., Cryptosporidium), particularly amoebae (e.g., Naegleria fowleri). Further microbial contaminants that are fungi include Trichophyton mentagrophytes and Aspergillus.

[0115] The articles, compositions and methods disclosed herein, including trivalent rare earth doped cerium oxide, reduce the concentration or amount of these biological contaminants.

[0116] Method for preparing novel trivalent doped cerium oxide particulate oxide compositions There are known methods for producing trivalent doped cerium oxide compositions (see, for example, U.S. Patent Application Serial No. 17 / 870,068, the entire contents of which are incorporated herein by reference). However, the methods disclosed herein are novel and provide novel particulate oxide compositions comprising trivalent rare earth doped cerium oxide having the unique depth profile and other unique properties described above. The methods produce particulate oxide compositions including all of the embodiments described above. These novel particulate oxide compositions are capable of reducing concentrations of biological contaminants and are made by the processes disclosed herein.

[0117] Particulate oxide compositions containing trivalent rare earth doped cerium oxide are made by intimately mixing trivalent rare earth carbonates, oxides or mixtures thereof, and cerium (IV) oxide with an aqueous solution of a soluble salt of a trivalent rare earth. If additional metal oxides are desired in the particulate oxide composition, they are included within the cerium (IV) oxide, such as by using cerium aluminum oxide or cerium zirconium oxide. The soluble salt of the trivalent rare earth can be any salt that is soluble in aqueous solution, including, for example, nitrates and chlorides. The concentration of the aqueous salt solution utilized can be from about 0.02 to about 3 mol / L.

[0118] In a particular embodiment, the trivalent rare earth oxide and cerium oxide are intimately mixed with an aqueous solution of a trivalent rare earth nitrate.

[0119] In these methods, the trivalent rare earth is a trivalent dopant in the particulate composition and may be selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof. The amounts of trivalent rare earth and soluble salts of trivalent rare earth carbonates, oxides, or mixtures thereof, and cerium (IV) oxide are selected to achieve the desired weight percentages of trivalent dopant and cerium oxide in the particulate oxide composition.

[0120] The resulting solid is heat treated to obtain a trivalent doped cerium oxide particulate composition. Heat treatment may be carried out at a temperature of about 200°C to about 1000°C for about 10 minutes to about 5 hours. This final heat treatment dries the resulting solid. In a particular embodiment, the temperature is about 550°C to about 800°C.

[0121] The trivalent doped cerium oxide particulate composition can then be used to prepare a support composition as disclosed herein for removing biological contaminants, comprising a support material and the trivalent doped cerium oxide particulate composition, the trivalent doped cerium oxide particulate composition being deposited on or in the support material. The trivalent doped cerium oxide particulate composition can also be used to prepare an article as disclosed herein comprising the support composition. The trivalent doped cerium oxide particulate composition can further be used in the methods described herein for removing biological contaminants.

[0122] Preparation of Support Compositions and Articles The support composition disclosed herein contains the particulate oxide composition and support material described herein. In a particular embodiment, the support composition comprises a novel particulate oxide composition comprising cerium oxide and a trivalent dopant, and having a unique depth profile as described above. The particulate oxide composition may optionally comprise additional metal oxides other than cerium oxide and a trivalent dopant. The particulate oxide composition is prepared as described above. The particulate oxide composition, the support composition and the article include all of the embodiments described herein. In the support composition, the support material is selected from an organic polymer, cotton, glass fiber, or a mixture thereof.

[0123] The particulate oxide composition of cerium oxide, trivalent dopant and optional additional metal oxide, and the support composition of the support material can be used independently to treat gaseous or aqueous mixtures. Or, the particulate oxide composition of cerium oxide, trivalent dopant, optional additional metal oxide, and the support composition of the support material can be incorporated into an article, such as a filter or plastic container, designed specifically for treating gaseous or aqueous mixtures. The filter can be a fixed bed. The filter can be used for gaseous or aqueous mixtures or streams, and thus for filtering gaseous or aqueous mixtures or streams.

[0124] In the support composition and articles containing the support composition, a particulate oxide composition containing trivalent doped cerium oxide is deposited on or in a support material to provide a support composition for removing biological contaminants.

[0125] The particulate composition of cerium oxide, trivalent dopant, and any additional metal oxides can be deposited on one or more exterior and / or interior surfaces of a support material. Those skilled in the art will generally understand that the interior surfaces of a support material are referred to as pores. The trivalent doped cerium oxide particulate composition described herein can be supported on a support material with or without a binder. In some embodiments, the trivalent doped cerium oxide particulate composition can be applied to a support material using any conventional technique, such as slurry deposition.

[0126] The process of preparing the support composition disclosed herein is not limited by any particular step or method, and can generally be any that results in the incorporation of the trivalent-doped cerium oxide particulate composition into or deposition on a support material. The process of incorporation of the trivalent-doped cerium oxide particulate composition into a support material includes mixing the trivalent-doped cerium oxide particulate composition into the manufacture of the support material. As an example, the trivalent-doped cerium oxide particulate composition can be added to molten polypropylene in a molding process. As another example, the trivalent-doped cerium oxide particulate composition can be added to a mixture of polyvinyl chloride resin, plasticizer, and stabilizer, and passed through a hot mixer followed by an extruder.

[0127] The process of depositing the trivalent doped cerium oxide particulate composition onto a support material includes mixing the trivalent doped cerium oxide particulate composition with an organic binder, either in a liquid or aqueous solution. The mixture of trivalent doped cerium oxide particulate composition and organic binder is then bonded to the support material by immersion of the support material or by coating the support material with the mixture by spreading or air brushing. The organic binder may also be used in a slurry deposition technique.

[0128] In certain embodiments, the organic binder is selected from the group consisting of citric acid, polyurethane diol, polyvinyl alcohol, polyvinylpyrrolidone, linseed oil, and mixtures thereof. Once the trivalent doped cerium oxide particulate composition is bound to the support material, the coated support can optionally be rinsed with water before drying to remove any residue not bound to the support. The coated support can then be optionally dried at a temperature greater than about 20° C. and less than about 300° C. for about 1-12 hours, or until sufficiently dry. In certain embodiments, the coated support can then be optionally dried at a temperature greater than about 20° C. and less than about 120° C.

[0129] In the case of a support material that can be melted, such as glass or plastic, the support can be heated to the point where the surface just begins to soften, and then the trivalent doped cerium oxide particulate composition can be placed on the surface so that it begins to mix with the semi-molten material. Upon cooling and resolidification, the trivalent doped cerium oxide particulate composition is incorporated into the surface of the support material. The temperature utilized will depend on the support material utilized. Those skilled in the art will be able to easily determine the appropriate temperature for the support material utilized. For example, this temperature for quartz glass is over 1000°C, for borosilicate glass it is about 500-600°C, and for PVC it ​​is about 200-300°C.

[0130] These solid supports can be utilized to form articles including filters and plastic articles.

[0131] The trivalent doped cerium oxide particulate compositions may also be incorporated into articles for high-touch surfaces, which may come into contact with biological contaminants by direct touch contact. Thus, articles for high-touch surfaces may also be utilized for the treatment of fluids, but also for the reduction of bacteria and / or viruses deposited by contact. These articles may be containers for liquids, elevator buttons, handrail covers for escalators or stairs, doors, door handles, door knobs, covers for public transport, touch pads for electronic transactions, fabrics, etc.

[0132] The support compositions and support materials containing the trivalent doped cerium oxide particulate compositions can be formed into elastic or rigid articles such as filters, fixed bed filtration systems, bottles or containers, high touch surfaces, etc. In certain embodiments, the articles are plastic articles. In other embodiments, the articles are filters. These articles may contain any additional necessary components that such articles normally contain, as will be well recognized by those skilled in the art. Techniques for forming these articles are well known to those skilled in the art.

[0133] Methods of using trivalent doped cerium oxide particulate compositions This application relates to methods for removing biological contaminants using any of the disclosed compositions containing trivalent doped cerium oxide. The methods may utilize the particulate oxide composition of cerium oxide, trivalent dopant, and any additional metal oxides by itself, or the methods may utilize the particulate oxide composition as part of a support composition or article. The methods can treat fluids, including air streams and aqueous and gaseous streams.

[0134] Without wishing to be bound by any theory, it is believed that the unique depth profile of the novel particulate oxide composition, such that there is a higher ratio of trivalent dopant to cerium at and near the surface of the particulate composition, may provide improved activity for removing biological contaminants.

[0135] In some embodiments, the particulate oxide composition comprising cerium oxide, a trivalent dopant, and any additional metal oxide, and the support composition comprising the support material may be used independently in a method for removing biological contaminants, or the particulate oxide composition and the support composition of the support material may be incorporated into an article, such as a filter or plastic container, specifically designed to treat gaseous or aqueous mixtures.

[0136] As described herein, the particulate oxide composition comprises cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf) and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant. In certain embodiments, the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. In these methods, it can be understood that the particulate oxide composition can have any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxide, and any of the above-mentioned properties.

[0137] In certain embodiments of the method, the present application relates to a method for removing biological contaminants and ensuring biological contaminants at or below a target concentration using the disclosed compositions containing trivalent doped cerium oxide. These biological contaminants include bacteria, viruses, protozoa (e.g., amoebas), fungi, algae, yeasts, and the like. These compositions include the particulate oxide composition itself, a support composition containing the particulate oxide composition, and an article containing a support composition containing the particulate oxide composition. In certain embodiments, these particulate oxide compositions are those that have a unique depth profile. It can be understood that the particulate oxide composition can have any of the above amounts of trivalent dopant, cerium oxide, and any additional metal oxide, and any of the above characteristics. These methods can treat a fluid (e.g., aqueous or gaseous stream) or a surface of a solid object by touch / direct contact. Thus, the methods disclosed herein include methods for treating a fluid (e.g., aqueous and / or gaseous stream).

[0138] In certain embodiments of the method, the aqueous or gaseous stream is contacted with a particulate oxide composition containing trivalent doped cerium oxide, including any of the above-mentioned embodiments, including any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxide, and any of the above-mentioned characteristics.

[0139] In other embodiments of the method, an aqueous or gaseous stream is contacted with a support composition containing a particulate oxide composition described herein. In yet other embodiments of the method, a potentially contaminated surface is contacted with a support composition or article containing a particulate oxide composition described herein. These potentially contaminated surfaces include, for example, skin (e.g., hands, fingers, palms, etc.), where contact is by touching a support composition or article containing a particulate oxide composition described herein. In the disclosed methods, the biological contaminants to be removed may be contained in an aqueous or gaseous stream, or may be on the surface of a physical object.

[0140] Without wishing to be bound by any theory, it is believed that contact of the particulate oxide compositions described herein with biological contaminants results in one or more of adsorption and / or reaction with the trivalent doped cerium oxide, or inactivation of the biological contaminants when contacted with the trivalent doped cerium oxide. By adsorbing, reacting and / or inactivating the biological contaminants with the trivalent doped cerium oxide, the biological contaminants are removed from biological contaminant-containing fluids (air or aqueous streams) or solid surfaces. Without wishing to be bound by any theory, the unique depth profile of the novel particulate oxide compositions, such that there is a higher ratio of trivalent dopant to cerium at and near the surface, may provide improved activity for removing biological contaminants.

[0141] Biological contaminants may be removed to a target level or below a target level. In some embodiments, biological contaminants may be removed to undetectable levels. The target level may be a specified amount or detection limit. As part of the methods described herein, the biological contaminants to be removed may be identified and a target amount or level of the contaminant may be set. For certain of the biological contaminants contemplated herein, the target amount or level may be any detectable amount. The method may optionally further include monitoring the treated stream for contaminants.

[0142] The methods disclosed herein may be used to treat air or water, or may be used to treat contaminants by contact with touch. When used to treat contaminants by contact with touch, the disclosed compositions are incorporated into high-touch surfaces.

[0143] The use of the disclosed particulate oxide compositions containing cerium oxide, trivalent dopants and optional additional metal oxides to treat biologically contaminated air and / or water allows for efficient operation of the air and / or water treatment process and provides treated streams with reduced concentrations of biological contaminants. As disclosed herein, the particulate oxide compositions may be incorporated into support compositions, which may be incorporated into articles specifically designed to treat gaseous or aqueous mixtures, such as filters, fixed bed filtration systems, or plastics for containers. In methods of treating aqueous streams, the particulate oxide compositions themselves may also be used and contacted by slurrying. In those methods involving slurrying, the method may further include filtering the fluid / liquid.

[0144] In any of these methods, the particulate oxide composition can have any of the above-mentioned amounts of trivalent dopant, cerium oxide, and any additional metal oxide, as well as any of the above-mentioned properties, including a unique depth profile.

[0145] Although the method of the present disclosure is contemplated for removing biological (e.g., bacterial, viral, amoeba, etc.) contaminants from air and / or drinking water and groundwater, it will be understood that the process can be used to treat any gaseous or aqueous liquid feed containing undesirable amounts of biological contaminants. The method is also contemplated for removing biological contaminants by direct contact of the contaminated surface with an article containing the particulate oxide composition described herein.

[0146] In certain embodiments, these methods include: (i) providing a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and, optionally, an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is greater than a ratio of the trivalent dopant to Ce at about 15 nm from the surface of the particulate composition; (ii) contacting the composition with a biological contaminant selected from the group consisting of bacteria, viruses, fungi, protozoa, and mixtures thereof; and (iii) removing the biological contaminant by contact with the composition. The biological contaminants may be contained in an aqueous or liquid stream or on the surface of an object that comes into physical contact with the compositions containing trivalent doped cerium oxide. These methods remove at least about 90% of the biological contaminants upon contact with the compositions.

[0147] In certain embodiments, the particulate oxide composition may be included within a support composition, and in certain of these embodiments, the support composition may be incorporated into an article. These methods may further include monitoring for biological contaminants after contacting. Monitoring may be by sampling or may be continuous.

[0148] The particulate oxide compositions used in these methods include all of the embodiments described above. The novel particulate oxide compositions with unique depth profiles are particularly capable of reducing concentrations of biological contaminants.

[0149] In certain embodiments, these methods include (i) providing a support composition comprising a particulate oxide composition comprising a support material comprising an organic polymer, cotton, glass fiber, and mixtures thereof, and a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; (ii) contacting the support composition with a biological contaminant selected from the group consisting of bacteria, viruses, fungi, protozoa, and mixtures thereof; and (iii) removing the biological contaminant by contact with the composition. In some of these embodiments, the particulate oxide composition has an average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. In some of these embodiments, the particulate oxide composition comprises cerium oxide in an amount of about 99.9% to about 20% by weight based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of about 0.1% to about 50% by weight based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 70% to about 0% by weight based on the total weight of the particulate oxide composition. The biological contaminants may be contained in the aqueous or liquid stream or on the surface of an object that is in physical contact with the composition containing the trivalent doped cerium oxide. These methods may further include monitoring the biological contaminants after contact. The monitoring may be by sampling or may be continuous. The particulate oxide compositions used in these methods include all of the above-mentioned embodiments. The novel particulate oxide compositions with unique depth profiles can specifically reduce the concentration of biological contaminants.

[0150] In certain embodiments, these methods include (i) providing a support composition comprising a support material comprising an organic polymer, cotton, fiberglass, or mixtures thereof, and a particulate oxide composition consisting essentially of cerium oxide and a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, (ii) contacting the composition with a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof, and (iii) removing the biological contaminant by contact with the composition. In this embodiment, the particulate oxide composition can have an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition, the particulate oxide composition comprising cerium oxide in an amount of about 99.9% to about 50% by weight based on the total weight of the particulate oxide composition; and trivalent dopant in an amount of about 0.1% to about 50% by weight based on the total weight of the particulate oxide composition. The biological contaminants can be contained in the aqueous or liquid stream or on the surface of an object that comes into physical contact with the composition containing the trivalent doped cerium oxide. These methods may further comprise monitoring for biological contaminants after contact. Monitoring may be by sampling or may be continuous.

[0151] The particulate oxide compositions of the methods described herein comprise (or in certain embodiments consist essentially of) cerium oxide and a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, with the cerium oxide being present in a greater amount than the trivalent dopant. In embodiments, the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate composition. The particulate oxide compositions used in these methods include all of the above-described embodiments, including any of the above-described amounts of trivalent dopant, cerium oxide and any additional metal oxide, and any of the above-described properties. The novel particulate compositions with unique depth profiles can reduce concentrations of biological contaminants, among others.

[0152] Contacting the particulate oxide composition with the biological contaminant results in a measurable amount of removal of the biological contaminant. In some embodiments, the contact removes at least about 90% of the biological contaminant. In other embodiments, the contact removes at least 95%, or more preferably 99% or 99%+ of the biological contaminant. Without wishing to be bound by any theory, the unique depth profile of the novel particulate oxide composition, such that there is a higher ratio of trivalent dopant to cerium at and near the surface, may provide improved activity for removing biological contaminants.

[0153] Contacting the particulate oxide composition with the biological contaminant effectively reduces the amount of the biological contaminant, and in certain embodiments, effectively reduces the amount of biological contaminant in a gaseous or aqueous stream. Removal can also be expressed as a percentage reduction in the concentration of the biological contaminant. In some embodiments, contacting the particulate oxide composition with the biological contaminant can reduce its concentration by more than about 75%. More typically, contacting the trivalent doped cerium oxide particulate composition with the biological contaminant can reduce its concentration by more than about 80%, more typically by more than about 85%, more typically by more than about 90%, more typically by more than about 95%, more typically by more than about 97.5%, more typically by more than about 99%, and even more typically by more than about 99.5%.

[0154] In certain embodiments, the methods may be for removing biological contaminants from a fluid or for treating a fluid. In these embodiments, the fluid may be a gaseous stream or an aqueous stream. In these embodiments, the method includes (i) providing a support composition comprising a particulate oxide composition comprising a support material comprising an organic polymer, cotton, glass fiber, and mixtures thereof, and a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; (ii) contacting a gaseous or aqueous stream containing a biological contaminant selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof with the composition, and (iii) removing the biological contaminant from the gaseous or aqueous stream by contact with the composition. In certain embodiments, the average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The biological contaminants may be removed in an amount of 90% or more. These methods may further include monitoring the biological contaminants after contacting. The monitoring may be by sampling or may be continuous.

[0155] In details of these embodiments for removing biological contaminants from a fluid or for treating a fluid, the particulate oxide composition comprises cerium oxide in an amount of about 99.9% to about 50% by weight, based on the total weight of the particulate oxide composition; and a trivalent dopant in an amount of about 0.1% to about 50% by weight, based on the total weight of the particulate oxide composition. The particulate oxide compositions used in these methods include all of the embodiments described above. These novel particulate oxide compositions are capable of reducing concentrations of biological contaminants.

[0156] In these methods of treating gaseous or aqueous streams, the methods may further include the step of setting a target concentration of a biological contaminant. In these methods, a biological contaminant of interest is identified and then a target concentration of that biological contaminant is set. The methods may further include the step of monitoring the biological contaminant in the treated stream. The monitoring may be done by sampling or may be continuous.

[0157] In certain embodiments, the method includes the steps of: (i) providing a composition comprising a particulate oxide composition comprising a support material comprising an organic polymer, cotton, glass fiber, and mixtures thereof, and a trivalent dopant selected from the group consisting of cerium oxide; yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; (ii) establishing a target concentration of a biological contaminant; (iii) contacting a gaseous or aqueous stream with the composition and removing the biological contaminant by contact with the composition to provide a treated stream; and (iv) monitoring the treated stream for the biological contaminant, wherein the biological contaminant is selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. In certain embodiments, the particulate oxide composition has an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide composition used in these methods includes all of the above-mentioned embodiments. These novel particulate oxide compositions with unique depth profiles can reduce the concentration of biological contaminants in particular. The target concentration can be set to a certain amount of contaminant (e.g., virus, bacteria, protozoa / amoeba, or fungus) or can be set to a detection limit. Monitoring of biological contaminants can be done by techniques well known to those skilled in the art. Monitoring can be done by sampling or can be continuous. Those skilled in the art understand real-time and continuous monitoring techniques for microbial contaminants, including viruses, bacteria, protozoa / amoeba, fungi, etc. These techniques include optical techniques and cell counters.

[0158] In certain embodiments of treating an aqueous stream, the method includes: (i) providing a particulate composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of the trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than a ratio of the trivalent dopant to Ce from about 15 nm from the surface of the particulate composition; (ii) contacting the aqueous stream with the composition and removing biological contaminants by contact with the composition to provide a treated aqueous stream, wherein the biological contaminants are selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. These methods may further include monitoring for biological contaminants after contacting. The monitoring may be by sampling or may be continuous. In certain embodiments, the methods may further include setting a target concentration of the biological contaminant and monitoring the treated aqueous stream for the biological contaminant. The target concentration may be a specified amount or detection limit. In these methods, the particulate oxide composition may be contained within a support composition or within an article, or the particulate oxide composition itself may be contacted with the aqueous stream by slurrying. In methods involving slurrying, the method may further include filtering the fluid / liquid. The particulate oxide composition used in these methods includes all of the embodiments described above.

[0159] In certain embodiments of treating an aqueous stream, the method includes: (i) providing a support composition comprising a support material comprising an organic polymer, cotton, glass fiber, and mixtures thereof, and a particulate composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; (ii) contacting the aqueous stream with the composition and removing biological contaminants by contact with the composition to provide a treated aqueous stream, wherein the biological contaminants are selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. The particulate composition may have an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide composition used in these methods includes all of the embodiments described above. These methods may further include monitoring for biological contaminants after contacting. The monitoring may be by sampling or may be continuous. In certain embodiments, the method may further include setting a target concentration of the biological contaminant and monitoring the treated aqueous stream for the biological contaminant. The target concentration may be a specified amount or detection limit.

[0160] In certain embodiments of treating a gaseous stream, the method includes: (i) providing a support composition comprising a support material comprising an organic polymer, cotton, glass fiber, and mixtures thereof, and a particulate composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; (ii) contacting the gaseous stream with the composition and removing biological contaminants by contact with the composition to provide a treated gaseous stream, wherein the biological contaminants are selected from the group consisting of bacteria, viruses, fungi (e.g., molds), protozoa (e.g., amoebas), and mixtures thereof. The particulate composition may have an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate oxide composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide composition used in these methods includes all of the embodiments described above. These methods may further include monitoring for biological contaminants after contacting. The monitoring may be by sampling or may be continuous. In certain embodiments, the method may further include setting a target concentration of the biological contaminant and monitoring the treated gaseous stream for the biological contaminant. The target concentration may be a specified amount or detection limit.

[0161] Where the biological contaminant is bacteria or fungus / mold, removal may be expressed as a % reduction determined by using colony forming units (CFU). In these embodiments, the concentration of the bacterial contaminant after contact with the particulate oxide composition or a support composition or article comprising the particulate oxide composition may be between about 45 colony forming units CFU / ml and 5×10 5 It can be CFU / ml.

[0162] When the biological contaminants are bacteria and / or viruses, removal can be expressed as a % reduction determined by using the Most Probable Number (MPN) technique, which is used to estimate the concentration of viable microorganisms in a sample by replicating liquid broth growth at 10-fold dilutions.

[0163] The target concentration of the biological contaminant can also be set as a percent reduction in the contaminant from before the method and after contact in the method. In certain embodiments, the percent reduction can be from about 75% to about 100% less. In other embodiments, the percent reduction can be from about 80% to about 99.9%.

[0164] The target concentration of a biological contaminant can be set at the detection limit for that contaminant. In embodiments that include setting a target concentration for a biological contaminant as described above, the method may further include one or more of the following additional steps: identifying the biological contaminant of interest, setting a target concentration, and monitoring the biological contaminant after the contacting step to determine or verify that the biological contaminant is below the target concentration. Depending on the biological contaminant, the target concentration may be any detectable amount of that contaminant, and the methods disclosed herein are effective for treating an aqueous or gaseous stream as long as no amount of that contaminant is detected in the treated stream.

[0165] In certain of these embodiments, the stream to be treated may be an aqueous stream and the target contaminant may be a bacterium, a virus, or a protozoan (e.g., an amoeba). For example, the stream to be treated may be an aqueous or gaseous stream and the target contaminant may be E. coli, poliovirus, coronavirus, Naegleria fowleri, paramyxovirus, Mycobacterium tuberculosis, Legionella pneumophila, coronavirus, or mixtures thereof. In certain embodiments, the stream to be treated is an aqueous stream and the target contaminant is E. coli, poliovirus, Naegleria fowleri, Legionella pneumophila, coronavirus, or mixtures thereof. In certain embodiments, the stream being treated is a gaseous stream and the target contaminant is a paramyxovirus, Mycobacterium tuberculosis, a coronavirus, or mixtures thereof. In certain embodiments, the target viruses are primarily transmitted by contact and include varicella zoster virus (VZV), variola viruses (including smallpox and monkeypox).

[0166] Certain of these methods include the steps of: (i) providing a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant; and (ii) establishing a target concentration of a biological contaminant, the contaminant being selected from the group consisting of Escherichia coli (E. coli), poliovirus, coronavirus, Naegleria fowleri, paramyxovirus, Mycobacterium tuberculosis, Legionella pneumophila, and the like. The method includes the steps of (i) contacting the gaseous or aqueous stream with a composition to remove the biological contaminant from the gaseous or aqueous stream selected from the group consisting of: pneumophila, coronavirus, or mixtures thereof; (ii) contacting the gaseous or aqueous stream with a composition to remove the biological contaminant by contact with the composition to obtain a treated stream; and (iii) monitoring the treated stream for the biological contaminant. The target concentration can be set at a fixed amount of the contaminant or can be set at a detection limit. The method may also include identifying the contaminant of interest prior to setting the target concentration.

[0167] The particulate oxide composition of step (i) may comprise from about 0.1% to about 50% by weight of trivalent dopant and may have an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide composition used in the method includes all of the above-mentioned embodiments. The particulate oxide composition of step (i) may also be provided as part of a support composition, thus further comprising a support material comprising an organic polymer, cotton, glass fiber, or mixtures thereof, or as part of an article comprising the support composition.

[0168] Examples of gaseous feeds that may be treated according to the methods disclosed herein include building ventilation systems, aircraft or vehicle ventilation systems, and ambient indoor air, among others. Examples of liquid feeds that may be treated according to the methods disclosed herein include tap water, well water, surface water such as water from lakes and marshes, water for recreational activities, agricultural water, wastewater from industrial processes, and geothermal fluids, among others. Examples of other applications involving physical contact with biological contaminants that are not filters include plastics for containers or plastics incorporated into high-touch surfaces, such as elevator buttons, escalator rail covers, stair rail covers, touch pads for electronic transactions, doors, doorknobs, and the like. These high-touch surfaces may also include glass or a mixture of glass and plastic.

[0169] The particulate oxide composition can remove bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds) and other microbial contaminants, and in some embodiments, can remove bacteria, viruses, protozoa (e.g., amoebas), fungi (e.g., molds) and mixtures thereof from a gas or liquid supply.

[0170] In one embodiment, the process is envisioned for removing biological contaminants from gaseous or aqueous streams using particulate oxide compositions. The gaseous stream may be one or more of an ambient air supply or a plurality of air supplies for a ventilation system that contain or may contain undesirable amounts of biological and / or other contaminants. The aqueous stream may be one or more of drinking water and groundwater supplies that contain or may contain undesirable amounts of biological and / or other contaminants. Additionally, the aqueous stream may include, but is not limited to, well water, surface water (including natural and artificial water and water for recreational purposes, such as water from lakes, ponds and marshes), agricultural water, wastewater from industrial processes, and geothermal water.

[0171] In some embodiments, the biological contaminant-containing gaseous stream passes through an inlet into a vessel at a temperature and pressure, typically ambient temperature and pressure, such that the gas in the biological contaminant-containing gaseous stream remains in a gaseous state. In the vessel, the biological contaminant-containing gaseous stream is contacted with a particulate oxide composition. Contact between the particulate oxide composition and the biological contaminant-containing gaseous stream removes the biological contaminants. Contact between the particulate oxide composition and the biological contaminant-containing gaseous stream removes a measurable amount of the biological contaminant, and in some embodiments, at least 90%, more preferably 95%, and even more preferably 99% or 99%+ of the biological contaminant is removed. The particulate oxide composition comprises cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf) and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant. In certain embodiments, the particulate oxide composition may comprise from about 0.1% to about 50% by weight of a trivalent dopant and may have an average ratio of trivalent dopant to Ce at about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide composition used in these methods includes all of the embodiments described above.

[0172] In some embodiments, the biological contaminant-containing aqueous stream passes through an inlet in a vessel at a temperature and pressure, typically ambient temperature and pressure, such that the water in the biological contaminant-containing aqueous stream remains in a liquid state. In the vessel, the biological contaminant-containing aqueous stream is contacted with a particulate oxide composition. Contact of the particulate oxide composition with the biological contaminant-containing aqueous stream removes a measurable amount of the biological contaminant, in some embodiments, removing at least 90%, more preferably 95%, and even more preferably 99% or 99%+ of the biological contaminant. The particulate oxide composition comprises cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr) and mixtures thereof, and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf) and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant. In certain embodiments, the particulate oxide composition may include from about 0.1% to about 50% by weight of a trivalent dopant and may have an average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition that is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate composition. The particulate oxide compositions used in these methods include all of the embodiments described above.

[0173] In some embodiments, the trivalent doped cerium oxide particulate composition is in the form of a fixed bed. Moreover, the fixed bed containing the trivalent doped cerium oxide particulate composition typically comprises particles containing trivalent doped cerium oxide. The trivalent doped cerium oxide particles may have a shape and / or morphology that exposes the maximum trivalent doped cerium oxide particle surface area to the gaseous or aqueous fluid with minimal back pressure and flow rate of the gaseous or aqueous fluid through the fixed bed. However, if desired, the trivalent doped cerium oxide particles may be in the form of a shaped body such as a bead, extrudate, porous polymer structure or monolith. The particles include all of the above-mentioned embodiments of trivalent doped cerium oxide. The trivalent doped cerium oxide particulate composition may be supported as a layer and / or coating on such a bead, extrudate, porous polymer structure or monolith support.

[0174] Contact of the trivalent doped cerium oxide particulate composition with the biological contaminant-containing fluid is typically conducted at a temperature of from about 1° C. to about 100° C., more typically from about 5° C. to about 40° C. Additionally, contact of the trivalent doped cerium oxide particulate composition with the biological contaminant-containing aqueous stream is typically conducted at a pH of from about pH 1 to about pH 11, more typically from about pH 3 to about pH 9. Contact of the trivalent doped cerium oxide particulate composition with the biological contaminant-containing fluid is typically conducted for a period of more than about 30 seconds and up to about 24 hours.

[0175] In general, the trivalent doped cerium oxide particulate compositions may be used to treat any biological contaminant, particularly bacteria, viruses, protozoa (e.g., amoebas), fungi, yeasts, and mixtures thereof. The novel trivalent doped cerium oxide particulate compositions of the present disclosure have several properties, which are described above, that are particularly advantageous for biological contaminant removal. Without wishing to be bound by any theory, it is believed that the unique depth profile of the novel particulate oxide compositions, such that there is a higher ratio of trivalent dopant to cerium at and near the surface, may provide improved activity for removing biological contaminants.

[0176] Contacting the particulate oxide composition with a gaseous or aqueous stream containing biological contaminants can effectively reduce the biological contaminant level in the gaseous or aqueous stream. Typically, contacting the particulate oxide composition with a biological contaminant can reduce its concentration by more than about 75%. More typically, contacting the particulate oxide composition with a biological contaminant can reduce its concentration by more than about 80%, more typically more than about 85%, more typically more than about 90%, more typically more than about 95%, more typically more than about 97.5%, more typically more than about 99%, and even more typically more than about 99.5%. If the biological contaminant is bacteria or mold, the reduction percentage can be determined by number using colony forming units (CFU). If the biological contaminant is bacteria or virus, the reduction percentage can be determined by most probable number (MPN).

[0177] A method of treating air or water to remove biological contaminants includes passing an air or water stream containing a first concentration of one or more undesirable biological contaminants through a material, article, or support composition comprising a particulate oxide composition, and obtaining a treated air or water stream having a concentration of the one or more undesirable biological contaminants that is less than the first concentration.

[0178] In certain embodiments, the biological contaminant to be removed is a virus. After contact with an article or support composition comprising the particulate oxide composition, the concentration of the virus can be at or below a target concentration of the virus. When treating air or a gaseous stream, the contacted (or treated) stream has a virus concentration at or below a target concentration of the virus. In particular of these embodiments, the virus is a coronavirus.

[0179] In certain embodiments, the biological contaminant removed is bacteria. After contact with an article or support composition comprising a particulate oxide composition, the concentration of bacteria can be at or below a target concentration of bacteria. When treating air or a gaseous stream, the contacted (or treated) stream has a bacterial concentration at or below a target concentration of bacteria. In a detail of these embodiments, the bacteria is fecal coliform bacteria.

[0180] In certain embodiments, the biological contaminant to be removed is a protozoan (e.g., amoeba). After contact with the article or support composition comprising the particulate oxide composition, the concentration of the protozoan (e.g., amoeba) may be equal to or less than the target concentration of the protozoan (e.g., amoeba). When treating air or gaseous streams, the contacted (or treated) stream has a protozoan (e.g., amoeba) concentration equal to or less than the target concentration of the protozoan (e.g., amoeba). In particular of these embodiments, the protozoan (e.g., amoeba) to be removed is Naegleria fowleri and / or Cryptosporidium.

[0181] In certain embodiments, the biological contaminant removed is a fungus (e.g., mold). After contact with an article or support composition comprising a particulate oxide composition, the concentration of the fungus may be at or below a target concentration of the fungus. When treating air or a gaseous stream, the contacted (or treated) stream has a fungus concentration at or below a target concentration of the fungus. In particular of these embodiments, the fungus removed is Trichophyton mentagrophytes and / or Aspergillus.

[0182] The concentration of contaminants after contact with a support composition or material or article containing the particulate oxide composition is between about 45 colony forming units CFU / ml and 5×10 5 The target concentration can be set at a certain amount of contaminant (e.g., virus, bacteria, amoeba, fungus) CFU per ml, or can be set at the limit of detection.

[0183] In some embodiments, the particulate oxide composition itself is slurried with the biological contaminant-containing aqueous stream. It can be understood that the particulate oxide composition and the biological contaminant-containing aqueous stream are in contact when slurried. Without wishing to be bound by any theory, it is believed that by slurrying and / or contacting the trivalent doped cerium oxide particulate composition with the biological contaminant-containing aqueous stream, a portion, if not most or all, of the biological contaminants contained in the biological contaminant-containing aqueous stream are removed from the biological contaminant-containing aqueous stream. After the particulate oxide composition is slurried and / or contacted with the biological contaminant-containing aqueous stream, the slurry is filtered by any known solid-liquid separation method. The particulate oxide composition utilized in the method including slurrying includes all of the particulate oxide composition embodiments described herein, particularly the unique depth profile. EXAMPLES

[0184] The following examples are provided to more fully illustrate the trivalent doped cerium oxide compositions and methods, but are in no way intended to limit the scope of the invention thereby.

[0185] Scanning electron microscope (SEM) images were collected using a FEG Zeiss ultra 55 (1 nm resolution). Transmission electron microscope (TEM) images were collected using a FEI Titan Themis 200 (0.09 nm resolution). Surface area, pore radius, and pore volume were measured by the BET / BJH method (ASTM D3663-20). Hg porosity and total Hg pore volume were measured using a Micromeritics Autopore IV 9500 system. The procedure outlined in ASTM International test method D 4284-07 was followed. Particle size was measured using a Microtrac S3500. X-ray diffraction was performed using a Bruker D2 Phaser X-ray diffractometer. Peak half-width was used to determine crystallite size. Zeta potential versus pH was measured using a procedure similar to ASTM E2865-12 (2018) using a Malvern Panalytical (Zetaziser Nano ZS) ZEN3600. As will be understood, crystallite size is the size of an individual crystal as measured by XRD or TEM. xxSize is the size of the particles formed from individual crystallites and measured by laser diffraction. Temperature programmed desorption of CO2 was performed as described in Hakim, A. et al., Temperature Programmed Desorption of Carbon Dioxide for Activated Carbon Supported Nickel Oxide: The Adsorption and Desorption Studies, Advanced Materials Research, Vol. 1087 (2015) pp 45-49. Temperature programmed reduction of hydrogen was performed as described in Hurst, NW et al., Temperature Programmed Reduction. Catalysis Reviews Science and Engineering, 24: 2, 233-309. Depth profilometry was performed as described in Noel, C. et al., ToF-SIMS Depth Profiling of Organic Delta Layers with Low-Energy Cesium Ions: Depth Resolution Assessment, Journal of The American Society for Mass Spectrometry, Vol. 30 (2019) pp 1537-1544.

[0186] Example 1 A trivalent doped cerium oxide composition was prepared by the following method: 68 g (0.297 mol) lanthanum carbonate and 464 g (2.7 mol) cerium oxide were mixed with 200 ml of 1.0 mol / L lanthanum nitrate solution. The ingredients were mixed for 2 hours. The mixture was then heated in a furnace to 550° C. for 2 hours, yielding 542 g of mixed cerium-lanthanum oxide with about 15% lanthanum oxide by weight, which may be referred to as La-doped cerium oxide.

[0187] Scanning electron microscope (SEM) images of a sample of the composition of Example 1 were collected and are displayed in Figures 1 and 2. The images show a porous material that is somewhat spherical in shape. Transmission electron microscope (TEM) images of a sample of the composition of Example 1 were collected and are displayed in Figures 3 and 4. The images reveal clusters of spheres. The surface area, pore radius, and pore volume of a sample of the composition of Example 1 were analyzed and found to be 98.332 m 2 / g(BET) and 135.268m 2 / g (BJH), pore radius was found to be 3.235 nm, and pore volume was 0.248 cc / g. The measured Hg porosity was measured to be 0.21 cc / g, pore diameter <1 μm was 0.46 cc / g, and total pore volume was 0.96 cc / g. The particle size distribution was measured as above, with D10 of 3.552 μm, D50 of 12.1 μm, and D90 of 43.12 μm. The crystallite size measured by XRD was determined to be 9.77 nm. The temperature programmed desorption profile is FIG. 5A. The desorption of CO2 has three peak temperatures at 172° C., 350° C., and 735° C., indicating both physisorption and chemisorption of CO2. The H2TPR is shown in FIG. 6, and shows a strong peak near 500° C. in contrast to Examples 2 and 3, which have broader peaks. The zeta potential as a function of pH is shown in Figure 7. The isoelectric point (IEP) was 8.1. LaO as a function of depth + versus 140 CEO + The ratio of LaO + vs. CeO + Note that the ratio of La is higher at shallower depths and approaches a constant level as depth increases, indicating that the concentration of La is higher at and near the surface for the material of Example 1. The material of Example 1 is an embodiment of trivalent doped cerium oxide with a unique depth profile.

[0188] Example 2 A trivalent doped cerium oxide composition was prepared by the following method, also described in U.S. Patent Application Serial No. 17 / 870,068: 129 ml of 1 mol / L Ce(NO3)4 solution was mixed with 24 ml of 1 mol / L La(NO3)3 solution. The resulting solution was heated to reflux for at least 2 hours. 5.5 mol / L NH4OH was then added to a pH of 10. The resulting solid was filtered and washed with DI water until the wash water was <15 mS / cm. The resulting powder was heated in a furnace in air at 550° C. for at least 2 hours to obtain a mixed cerium lanthanum oxide with about 15% lanthanum oxide by weight, which may be referred to as La-doped cerium oxide.

[0189] Figures 10 and 11 are SEM images. The images show the porous material to be somewhat spherical in shape. Figures 12A-12D include TEM images. Clusters of spheres are evident in the images and diffracting planes can be seen. The surface area is 120.464 m 2 / g(BET) and 143.087m 2 / g (BJH), the pore radius was found to be 3.245 nm, and the pore volume was found to be 0.285 cc / g. The pore volume of pores with diameters <0.1 μm was measured to be 0.23 cc / g, the pore volume of pores with diameters <1 μm was measured to be 0.45 cc / g, and the total pore volume was 0.99 cc / g. The particle size distribution was measured as above, with D10 of 1.301 μm, D50 of 5.545 μm, and D90 of 13.109 μm. The crystallite size measured by XRD was determined to be 9.03 nm. The temperature programmed desorption profile is Figure 5B. The desorption of CO2 has one peak temperature at 175 °C, indicating only physisorption of CO2. Any peaks at higher temperatures are not distinguished from the background, and therefore no chemisorption of CO2 is detected. The H2TPR is shown in Figure 6, showing a broad peak near 566 °C. The zeta potential as a function of pH is shown in Figure 7. The isoelectric point (IEP) was 7.34.

[0190] LaO as a function of depth + versus 140 CEO + The ratio of LaO to the surface is plotted in Figure 8. This material exhibits a nearly constant LaO+ vs. CeO + Note that the ratio of La is approximately the same at the surface as it is at depth.

[0191] Example 3 A cerium (IV) oxide composition was prepared by the following method: In a closed stirred vessel, 1 liter of 0.12 M cerium (IV) ammonium nitrate solution was prepared from cerium (IV) ammonium nitrate crystals dissolved in nitric acid and held at approximately 90° C. for approximately 24 hours. In a separate vessel, 200 ml of 3 M ammonium hydroxide solution was prepared and held at room temperature. The two solutions were then combined and stirred for approximately 1 hour. The resulting precipitate was filtered using a Buchner funnel equipped with filter paper. The solid was then washed thoroughly in the Buchner using deionized water. Following the washing / filtration step, the wet hydrate was calcined in a muffle furnace at approximately 450° C. for 3 hours to form the cerium (IV) oxide composition.

[0192] The surface area is 126 m 2 / g(BET) and 167m 2 / g (BJH), the pore radius was found to be 3.62 nm, and the pore volume was found to be 0.309 cc / g. The pore volume of pores with a diameter of <0.1 μm was measured to be 0.24 cc / g, the pore volume of pores with a diameter of <1 μm was measured to be 0.35 cc / g, and the total pore volume was 0.85 cc / g. The particle size distribution was measured as described above, with a D10 of 2 μm, a D50 of 9 μm, and a D90 of 25 μm. The crystallite size measured by XRD was determined to be 8.43 nm. The temperature programmed desorption profile is shown in Figure 5C. The desorption of CO2 has one peak temperature at 175 °C, indicating only physisorption of CO2. Any peaks at higher temperatures are not distinguished from the background, and therefore no chemisorption of CO2 is detected. The H2TPR is shown in Figure 6, showing broad peaks near 500 and 900 °C. The zeta potential as a function of pH is shown in Figure 7. The isoelectric point (IEP) was 7.22.

[0193] Depth profilometry was not performed since Ce was the only component in this sample. This sample did not contain any trivalent dopants.

[0194] Example 4 A trivalent doped cerium oxide composition was prepared by the following method: In a closed stirred vessel, 1 liter of 0.12 M cerium(IV) ammonium nitrate solution was prepared from cerium(IV) ammonium nitrate crystals dissolved in nitric acid. To this, 199.5 g (0.5 mol) of commercially available Al(NO3)3 was added and held at about 90°C for about 24 hours. In a separate vessel, 200 ml of 3 M ammonium hydroxide solution was prepared and held at room temperature. The two solutions were then combined and stirred for approximately 1 hour. The resulting precipitate was filtered using a Buchner funnel equipped with filter paper. The solid was then washed thoroughly in the Buchner using deionized water. Following the washing / filtration step, the wet hydrate was calcined in a muffle furnace at about 450°C for 3 hours to form an aluminum cerium(IV) oxide composition. This oxide was suspended in a praseodymium nitrate solution containing praseodymium carbonate. The ratio of Pr to aluminum cerium (IV) oxide was varied to achieve 4%, 8%, 12% or 20% loading of Pr oxide in the final product. The ingredients were mixed for 2 hours. The mixture was then heated in a furnace to 550°C for 2 hours to obtain mixed cerium aluminum praseodymium oxide, which may also be called Pr-doped cerium oxide.

[0195] The depth profile of each of these materials was then measured, and the PrO versus depth + versus 140 CEO + The ratio of trivalent, in this case PrO, is shown in Figure 9. As in Example 1, + of 140 CEO + The ratio to is higher at the surface and at shallow depths and approaches a constant level with increasing depth. The material of Example 9 is an embodiment of trivalent doped cerium oxide with a unique depth profile.

[0196] Example 5 A praseodymium-doped cerium oxide composition was prepared by the following method. The method is similar to that of Example 2. 129 ml of 1 mol / L Ce(NO3)4 solution was mixed with 82 ml of 1 mol / L Pr(NO3)3 solution and 63.9 g (0.3 mol) of commercial Al(NO3)3. The resulting solution was heated to reflux for at least 2 hours. Then, 5.5 mol / L NH4OH was added to pH 10. The resulting solid was filtered and washed with DI water until the wash water was <15 mS / cm. The resulting powder was heated in a furnace in air at 550°C for at least 2 hours to obtain a mixed cerium aluminum praseodymium oxide containing about 16% Pr oxide by weight. This may also be called Pr-doped cerium oxide.

[0197] Depth profiles were measured and the data are shown in Figure 9. As in Example 2, 140 CEO + trivalent for PrO + The ratio of is almost constant from the surface to the maximum measured depth, indicating that the Pr concentration is almost the same at the surface as it is deep inside.

[0198] The depth profile data from Examples 1, 2, 4 and 5 were then analyzed to determine the trivalent Ce to Ce ratio (LaO + / CeO + or PrO + / CeO + ) was compared. This average was then compared to the same ratio at a depth of 15 nm. The % increase was then calculated as ((average of 0-3.5 nm)-(ratio at 15 nm)) / (ratio at 15 nm) x 100. [Table 1]

[0199] Example 6 Virus removal properties of the compositions of Example 1 and Example 3. A quantitative suspension test was performed to evaluate the virucidal activity in the medical field. A coronavirus surrogate, enveloped DNA virus-vaccinia, was selected for screening and contained the following cell culture media: Eagle's Minimum Essential Medium (EMEM) + 10% FBS + 2% Pen / Strep (culture medium), EMEM + 2% FBS + 2% FCS + 1% Pen / Strep (virus medium). The test material concentration was 0.1 ± 0.01 g / mL-1, and distilled water was used as the diluent. The suspended powder was liquid vortexed until homogeneous. Contact analysis was performed over two immersion times of 30 ± 5 minutes. The test temperature was maintained at 20 ± 2 °C with incubation conditions of 37 ± 2 °C and 5% CO2. There were no interfering substances and the test product appeared normal and stable. The activity inhibition method was dilution with ice-cold medium to remove passive precipitation. No filtration was used. [Table 2]

[0200] Example 7 The virus removal properties of the composition of Example 1 and a commercially available silver zinc zeolite antimicrobial (CAS number 130328-20-0) material were tested using an adapted EN 14476 method. A 4 ml volume of suspension of these materials (0.2 g / ml in deionized water) was added to a mixture of 0.5 ml of vaccinia virus (ATCC® VR-1508™) suspension and 0.5 ml of hard water at room temperature (20±1° C.). At the indicated times (1 h and 4 h), 0.5 ml of the test mixture was placed in 4.5 ml of ice-cold EMEM and the mixture was left in an ice bath for 30 min±10 s. The samples were applied in two 100 μL portions to a MicroSpin™ S-400 HR column. The flow-through was treated with PMAxx™ dye and activated with a PMA-Lite™ LED photolysis device. Nucleic acids were extracted from the PMAxx™-treated viruses according to the kit instructions. Quantitative PCR was performed on extracted nucleic acids using the SYBR Green detection system. [Table 3]

[0201] Example 8 The bacterial removal properties of the composition of Example 1 and a commercially available silver zinc zeolite antimicrobial material (CAS number 130328-20-0) were tested using the adapted EN 13727 method. A 4 ml amount of suspension of these materials (0.2 g / ml in deionized water) was added to a mixture of 0.5 ml of Methicillin-Resistant Staphylococcus aureus (MRSA) ATCC® 43300™ suspension and 0.5 ml of hard water at room temperature (20±1° C.). 0.5 mL of the mixture was then transferred to a tube containing 4 mL of neutralizing agent (Dey Engley broth) and incubated at 20° C.±1° C. for 5 minutes±10 seconds. A challenge suspension (0.5 mL) was then added to each neutralizing tube, mixed, and incubated at 20° C.±1° C. for 30 minutes±1 minute. The suspensions were inoculated into TSA and evaluated for efficacy and toxicity. [Table 4]

[0202] Example 9 The relative bacterial removal properties were measured by the following procedure. On the day of testing, the purity and concentration of the bacterial cultures were checked. The reference bacteria (E. coli) was homogenized for 30 seconds and allowed to settle for 15 minutes. The microbial challenge was checked for purity and then diluted with phosphate buffered saline (PBS). The test was then performed in duplicate as follows: 100 microliters of a single diluted bacterial species suspension was added to a 50 mL conical tube (Corning) containing 0.25 g of the selected test material suspended in 25 mL of Sterile DI water, and a NIST traceable laboratory timer was immediately started. The mixture was homogenized at medium speed by vortexing periodically for a total contact time of 5 minutes. Immediately after, 1 mL of the sample was transferred to a new 50 mL tube containing 9 mL of D / E neutralizing broth (reference) and homogenized. On the day of testing, the samples were analyzed directly and at various dilutions in at least two replicates. Positive and negative controls were run alongside the test subjects to provide quality control and baseline data according to laboratory standard accredited ISO17025:2017 methodology. Bacteria were analyzed and enumerated as colony forming units (CFU) on the respective media according to SM 9215C. For the purpose of comparing material performance, the respective reduction rates were determined based on the recovery rates of the positive control and test samples and normalized on a logarithmic scale to Example 2. [Table 5]

[0203] Example 10 The relative bacterial removal properties were measured by the following procedure: An aliquot of OC43 virus was added to sterile DI water and homogenized. 25 mL of prepared test water was added to a 50 mL conical tube (Corning) containing 0.25 g of test material and a NIST traceable laboratory timer was immediately started. The mixture was homogenized on an orbital shaker at medium speed for a total contact time of 30 minutes. Immediately after, 1 mL of sample was transferred to a new 50 mL tube containing 9 mL of D / E neutralization broth (reference) and homogenized. Recovery controls consisted of sterile tubes containing 25 mL of test water homogenized and treated in the same manner as the test material. On the day of testing, samples were analyzed directly and at various dilutions in at least five replicates. Positive and negative controls were run alongside the test subjects to provide quality control and reference data according to laboratory standard accredited ISO17025:2017 methodology. Human coronavirus OC43 (ATCC VR-1558) virus was propagated using human ileocecal colorectal adenocarcinoma HCT-8 cell line (ATCC CCL-244) as a host and enumerated as most probable number (MPN). Cells were grown in 6-well plate cell culture flasks. For enumeration, viruses were enumerated as infectious units according to the assay methodology described in standard method 9510 (APHA, 2012). The methodology is equivalent to EPA / 600 / R-95 / 178 and updated EPA / 600 / 4-84 / 013. Briefly, aliquots of samples containing virus were seeded (approximately 90% confluence) onto freshly prepared monolayers of HCT8 cells. Each sample volume was seeded in replicates of 5. The cells were then incubated in Dulbecco's modified Eagle's medium (dMEM, Mediatech Inc., USA) medium 2% fetal bovine serum (FBS, Mediatech, USA) at 35 °C and 5% CO2 for 8-10 days. The cells were routinely monitored by microscopy for signs of degeneration. Cells in flasks showing signs of infectivity (cytopathic effect; CPE) were scored as positive (+) and cells that did not show CPE were scored as negative (-). The most likely number of infectious viruses in the samples was then calculated using MPNCALC software (version 0.0.0.23). Based on the recovery rates of the positive control and test samples, the respective percentage reduction was determined.For the purpose of comparing material performance, the percent reductions were determined based on the percent recovery of the positive control and test samples and normalized to Example 2 on a logarithmic scale. [Table 6]

[0204] Example 11 The material of Example 1 is suspended in deionized water and a binder such as citric acid is added to the water. A substrate such as cotton fabric is then dipped into the suspension at least once. The substrate is removed and then dried. The resulting fabric has a coating of the composition of Example 1 on its surface. This coated fabric is then placed in a funnel such that the fabric remains in the funnel as the water passes through. Water contaminated with E. coli is then poured into the funnel and allowed to come into contact with the coated fabric. The water collected from the funnel is analyzed and it is found that the concentration of E. coli has been reduced.

[0205] Example 12 The material of Example 1 is suspended in deionized water and a binder, such as citric acid, is added to the water. A substrate, such as cotton fabric, is then dipped into the suspension at least once. The substrate is removed and then dried. The resulting fabric has a coating of the composition of Example 1 on its surface. The coated fabric is then placed over an air filter such that the fabric covers the surface of the air filter and allows air to pass through the fabric. The filter is then placed in an HVAC or indoor air filtration unit. When the device is turned on, air contaminated with coronavirus passes through the filter. The air exhausted from the unit is analyzed and found to have a reduced concentration of coronavirus.

[0206] Example 13 Polyethylene granules or powder are mechanically mixed with the material of Example 1 such that the material of Example 1 is approximately 1% by weight. The mixture is then fed into a heating chamber to form an end-use product such as a bottle. After a bottle is formed from the polyethylene-containing material of Example 1, the surface to the polyethylene is tested for antibacterial or bacteriostatic properties by exposing the surface to E. coli. The surface is then analyzed for E. coli and found to have fewer colony forming units than the control. Another test is performed by placing pasteurized milk in the formed bottle and observing the time required for the milk to spoil. The milk takes a longer time to spoil compared to a polyethylene bottle that does not contain the material of Example 1.

[0207] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and the like used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained.

[0208] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the technology are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible, however, any numerical values ​​inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0209] It will be apparent that the compositions and methods described herein are well adapted to achieve the objects and advantages mentioned, as well as those inherent therein. Those skilled in the art will recognize that the methods and systems herein can be implemented in many ways and are therefore not limited by the illustrated embodiments and examples set forth above. In this regard, any number of features of the different embodiments described herein can be combined into one single embodiment, and alternative embodiments having less than or more than all of the features described herein are possible.

[0210] While various embodiments have been described for purposes of this disclosure, various changes and modifications can be made that are within the scope fully contemplated by this disclosure. Numerous other variations may be made that are encompassed by the spirit of this disclosure, as will be readily apparent to those skilled in the art.

Claims

1. A particulate oxide composition comprising: Cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally comprising an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof; A particulate oxide composition, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition.

2. 2. The particulate oxide composition of claim 1, cerium oxide in an amount of about 99.9 wt. % to about 20 wt. %, based on the total weight of the particulate oxide composition; a trivalent dopant in an amount of from about 0.1 wt. % to about 50 wt. % based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 70 wt. % to about 0 wt. % based on the total weight of said particulate oxide composition; 1. A particulate oxide composition comprising:

3. 2. The particulate oxide composition of claim 1, cerium oxide in an amount of about 99.9 wt. % to about 50 wt. %, based on the total weight of the particulate oxide composition; and a trivalent dopant in an amount of from about 0.1% to about 50% by weight based on the total weight of said particulate oxide composition; 1. A particulate oxide composition comprising:

4. 2. The particulate oxide composition of claim 1, cerium oxide in an amount of about 20% to about 30% by weight based on the total weight of said particulate oxide composition; a trivalent dopant in an amount of from about 2 wt. % to about 25 wt. % based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 45% to about 78% by weight based on the total weight of said particulate oxide composition; 1. A particulate oxide composition comprising:

5. 2. The particulate oxide composition of claim 1, cerium oxide in an amount of about 45 wt. % to about 78 wt. % based on the total weight of said particulate oxide composition; a trivalent dopant in an amount of from about 2 wt. % to about 25 wt. % based on the total weight of the particulate oxide composition; and an additional metal oxide in an amount of about 20% to about 30% by weight based on the total weight of said particulate oxide composition; 1. A particulate oxide composition comprising:

6. 2. The particulate oxide composition of claim 1, wherein the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is from about 10% to about 250% greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition.

7. 2. The particulate oxide composition of claim 1, wherein the average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate composition is from about 15% to about 250% greater than the ratio of trivalent dopant to Ce from about 15 nm from the surface of the particulate oxide composition.

8. 10. The particulate oxide composition of claim 1 comprising from about 2% to about 30% by weight of the trivalent dopant.

9. The composition comprises CO ２ 10. The particulate oxide composition of claim 1, exhibiting chemisorption and physisorption of

10. 1. A support composition for removing biological contaminants, comprising: a support material comprising an organic polymer, cotton, glass fiber, or a mixture thereof; and the particulate oxide composition of claim 1, The particulate oxide composition of claim 1 is deposited on or in the support material. Support composition.

11. 11. The support composition of claim 10, wherein the support material is an organic polymer selected from the group consisting of polyethylene, polyvinyl chloride, nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof.

12. The support composition of claim 10, wherein the support material is cotton.

13. The support composition of claim 10, wherein the indicator composition comprises from about 0.5 to about 80 weight percent of the particulate oxide composition, based on the total weight of the support composition.

14. The support composition of claim 10, wherein the support composition is a filter material or a plastic.

15. 1. A method for removing biological contaminants, comprising: a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; contacting the composition with a biological contaminant selected from the group consisting of bacteria, viruses, protozoa, fungi, and mixtures thereof; and removing at least about 90% of said biological contaminants by contact with said composition. A method comprising:

16. 16. The method of claim 15, wherein the particulate oxide composition is contained within a filter material or plastic.

17. 16. The method of claim 15, wherein the particulate oxide composition is deposited on or within a support material comprising an organic polymer, cotton, fiberglass, or a mixture thereof.

18. 16. The method of claim 15, wherein the composition removes approximately 99% or more of the biological contaminants.

19. 16. The method of claim 15, wherein the biological contaminant is in an aqueous stream.

20. 16. The method of claim 15, wherein the biological contaminant is in a gaseous stream.

21. 16. The method of claim 15, wherein said contacting is by solid touch to an article comprising said particulate oxide composition.

22. 16. The method of claim 15, further comprising the steps of setting a target concentration of the biological contaminant and monitoring the biological contaminant after contacting.

23. 1. A method for treating a fluid, comprising: (i) providing a particulate oxide composition comprising cerium oxide; a trivalent dopant selected from the group consisting of yttrium (Y), lanthanum (La), neodymium (Nd), praseodymium (Pr), and mixtures thereof; and optionally an additional metal oxide selected from the group consisting of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), and mixtures thereof, wherein the cerium oxide is present in an amount greater than the trivalent dopant, and wherein an average ratio of trivalent dopant to Ce from about 0 nm to about 3.5 nm from the surface of the particulate oxide composition is greater than the ratio of trivalent dopant to Ce at about 15 nm from the surface of the particulate oxide composition; (ii) contacting a gaseous or aqueous stream containing a biological contaminant selected from the group consisting of bacteria, viruses, fungi, protozoa, and mixtures thereof with the composition; and (iii) removing biological contaminants from said gaseous or aqueous stream by contact with said composition. A method comprising:

24. 24. The method of claim 23, wherein the particulate oxide composition is deposited on or within a support material comprising an organic polymer, cotton, fiberglass, or a mixture thereof.

25. A plastic article comprising:

10. A support composition for removing biological contaminants comprising: (a) an organic polymer selected from the group consisting of polyethylene, polyvinyl chloride, nylon, polypropylene, polyester, polyurethane, polyamide, polyolefin, polycarbonate, copolymers thereof, and mixtures thereof; and the particulate oxide composition of claim 1, wherein the particulate composition is deposited on or within the organic polymer; A plastic article comprising about 50 to about 100 weight percent of said support composition for removing biological contaminants, based on the total weight of said plastic article.

26. 26. The support composition of claim 10 or the article of claim 25 in a rigid or elastic form.

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