Method for removing polyvinylpyrrolidone from water using salt and method for using the precipitated composition for further water treatment

Abstract

A method for removing polyvinylpyrrolidone (PVP) from water using rare earth salts, iron salts, or mixtures thereof effectively and efficiently removes unwanted dissolved PVP and provides a composition containing ion-bound hydrolyzed PVP (h-PVP). In these compositions, the ions include rare earth cations, iron cations, and mixtures thereof. The composition is useful for removing aqueous contaminants from water, such as phosphates, other phosphorus-containing compounds, arsenic, arsenic-containing compounds, fluoride, and PFAS.

Description

[Technical Field]

[0001]

[0000] Related Applications This application claims priority to U.S. Provisional Application No. 63 / 415,164, filed October 11, 2022, the complete disclosure of which is incorporated herein by reference in its entirety.

[0001] FIELD OF THE INVENTION The present disclosure relates to a method for removing polyvinylpyrrolidone from water using rare earth salts, iron salts, or mixtures thereof. The disclosure further relates to a composition formed from this removal and then to using the composition as a soil amendment or filter for water treatment, particularly for treating water to remove phosphorus, arsenic, fluoride, or PFAS contaminants. [Background technology]

[0002] Anthropogenic contaminants in water are becoming a growing concern worldwide. Therefore, methods for removing these contaminants, especially those that are difficult to remove, continue to be needed. One such contaminant is polyvinylpyrrolidone (PVP), of all varieties. PVP is commonly referred to as polyvidone or povidone. Its characteristic structure is a polyethylene backbone with γ-lactam units attached to every other carbon on the backbone by carbon-nitrogen bonds. PVP can be manufactured in a variety of molecular weights. Invented around 1939, PVP was initially used as a plasma substitute, but is now used in many applications and products, including membranes, emulsifiers, glue sticks, batteries, ceramics, glass fibers, inks, tooth-bleaching gels, personal care products, and surfactants, to name just a few. While PVP is generally recognized as safe (GRAS), there are growing concerns regarding the environmental impact of high-molecular-weight substances such as PVP. Part of the concern stems from PVP's tendency to bioaccumulate and its extreme resistance to biodegradation and oxidation.

[0003] Reaction of PVP with ozone or peroxide does not degrade the polymer but converts the γ-lactam to a succinimide. For this reason, removal of PVP from water appears difficult. PVP is highly soluble in polar solvents such as water and is therefore difficult to precipitate. Traditional aeration-based degradation methods have been reported to be ineffective. Filtration methods such as reverse osmosis (RO) or nanofiltration theoretically work but suffer from challenges such as clogging, high costs, and disposal of stubborn water. Sorption methods show promise, but are impractical at high concentrations, and disposal of the sorption media can be problematic. While specific microorganisms have been reported, targeting specific microorganisms can also be difficult. In summary, PVP is difficult to remove, and traditional methods appear to be ineffective.

[0004] There remains a need in the art for effective methods for removing PVP from water sources. Summary of the Invention

[0005] The present disclosure relates to a method for removing PVP from water. The present disclosure also relates to a composition for treating water, comprising hydrolyzed PVP (h-PVP) and cations, wherein the cations are bound to the h-PVP. In the PVP composition, the cations are selected from rare earth cations, iron cations, or mixtures thereof. These compositions can be used as adsorption media for water treatment, particularly for treating water to remove phosphorus, arsenic, fluoride, or PFAS contaminants. Therefore, these compositions can be included in soil amendments or filters.

[0006] The present disclosure includes a method for removing unwanted dissolved PVP from water that combines PVP hydrolysis with the addition of rare earth salts, iron salts, or mixtures thereof. This method provides for removal of PVP by standard solid-liquid separation techniques, such as sedimentation and filtration. The precipitated solid (i.e., h-PVP with bound rare earth and / or iron cations) can then be used as an adsorption medium for removing contaminants, such as phosphate, from water. Thus, the present disclosure addresses the need for removing PVP from water and also creates a use for an otherwise discarded product.

[0007] Disclosed herein is a method for removing polyvinylpyrrolidone (PVP) from an aqueous stream. The method includes (i) providing an aqueous stream having a first PVP concentration, (ii) hydrolyzing the aqueous stream to provide an aqueous stream containing h-PVP, (iii) contacting the aqueous stream containing h-PVP with a rare earth salt, an iron salt, or a mixture thereof to precipitate cation-bound h-PVP, and (iv) providing a treated aqueous stream having a PVP concentration lower than the first PVP concentration. In certain embodiments, the salt is a rare earth salt, and the cations bound to the h-PVP are rare earth cations. In other embodiments, the salt is a mixture of a rare earth salt and an iron salt.

[0008] Also disclosed herein are h-PVP compositions for treating water. The h-PVP compositions can be incorporated into soil conditioners or filters. The compositions include hydrolyzed PVP (h-PVP) and ions bound to the h-PVP. Thus, the compositions for treating water include (a) h-PVP and (b) rare earth cations, iron cations, or mixtures thereof, where the cations are bound to the h-PVP, and the compositions include about 1% to about 50% by weight of the cations, based on the total weight of the composition, excluding any water present in the composition. In certain embodiments, the compositions include about 1% to about 40% by weight of the cations, based on the total weight of the composition, excluding any water present in the composition. In certain embodiments, the cations are rare earth cations. In some of these embodiments, the h-PVP is about 20% to about 75% hydrolyzed.

[0009] Also disclosed herein is a method for removing contaminants from an aqueous stream using a composition comprising h-PVP and ions bound to h-PVP. This method for removing contaminants from an aqueous stream includes: (i) contacting an aqueous stream having a first contaminant concentration with a water treatment composition comprising (a) h-PVP and (b) rare earth cations, iron cations, or a mixture thereof, wherein the cations are bound to h-PVP, and the composition comprises about 1% to about 50% by weight of the cations, based on the total weight of the composition, excluding any water present in the composition; (ii) removing the contaminants from the aqueous stream by contacting the aqueous stream with the composition; and (iii) providing a treated aqueous stream having a second contaminant concentration lower than the first contaminant concentration, wherein the contaminants are selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof. In certain embodiments, the cations are rare earth cations. In other embodiments, the cations are a mixture of rare earth cations and iron cations. In certain embodiments, the second contaminant concentration is about 50% to about 90% lower than the first contaminant concentration.

[0010] The method may further include setting a target contaminant concentration and monitoring the concentration of the second contaminant to ensure that the concentration of the second contaminant is at or below the target concentration. With these additional steps, the method may further include comparing the concentration of the second contaminant to the target concentration and replacing the composition for treating the water if the concentration of the second contaminant in the treated aqueous stream exceeds the target concentration. The method may further include monitoring the concentration of the second contaminant and replacing the composition for treating the water if the concentration of the second contaminant in the treated aqueous stream begins to increase.

[0011] Also disclosed is an integrated process for removing PVP from an industrial aqueous stream and reusing the removed PVP to remove contaminants from water. The integrated process includes the steps of: (i) providing an industrial aqueous stream having a first PVP concentration; (ii) hydrolyzing the industrial aqueous stream to provide an aqueous stream containing h-PVP; (iii) contacting the h-PVP-containing aqueous stream with a rare earth salt, an iron salt, or a mixture thereof to precipitate h-PVP having rare earth cations, iron cations, or a mixture thereof bound to the h-PVP; and (iv) isolating the precipitated h-PVP with bound cations. In certain embodiments, the salt and resulting cations are rare earths or mixtures of rare earths and iron.

[0012] The precipitated h-PVP with bound cations is then used to treat water containing contaminants. This portion of the integrated method includes (v) contacting a water stream having a first contaminant concentration with the precipitated h-PVP with bound cations to remove contaminants from the water stream, and (vi) providing a treated stream having a second contaminant concentration lower than the first contaminant concentration. In this integrated method, the contaminant is selected from the group consisting of phosphate, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof.

[0013] This integrated method may further include setting a target contaminant concentration or a target PVP concentration and monitoring to ensure that they are at or below the target concentration. With these additional steps, the method may further include comparing the concentration of a second contaminant and / or PVP to the target concentration. With respect to the concentration of a second contaminant, the method may further include replacing or renewing the h-PVP composition for treating the water if the concentration of the second contaminant in the treated aqueous stream exceeds the target concentration. Thus, the method may further include monitoring the concentration of the second contaminant and replacing / renewing the h-PVP composition for treating the water if the concentration of the second contaminant in the treated aqueous stream begins to increase. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a general flow diagram for removing PVP from water by hydrolysis followed by rare earth addition.

[0015] [Figure 2] FIG. 2 is a general flow diagram for removing contaminants using a cation-bound hydrolyzed PVP (h-PVP) composition.

[0016] [Figure 3] FIG. 3 is a plot of the phosphate removal capacity of the hydrolyzed compositions. DETAILED DESCRIPTION OF THE INVENTION

[0017] Before the methods and compositions for treating water 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 those skilled in the art. It is also to be understood that the terminology used herein is used only for the purpose of describing particular embodiments and is not intended to be limiting. It should be 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 "an amendment composition" or "a PVP composition" should not be construed as limiting in quantity or source, a reference to "a step" may include multiple steps, a reference to "producing" or "products" of a reaction or process should not be construed as all of the products of the reaction / process, and a reference to "processing" may include 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.

[0018] Numerical values ​​containing "about" include typical experimental variance. As used herein, the term "about" means within a statistically significant range of values, such as a stated particle size, weight percent, concentration range, time frame, 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 stated 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, all integers within that range are contemplated as embodiments of the invention.

[0019] This application relates to a method for removing polyvinylpyrrolidone (PVP) from a water source. It has been discovered that one process that can aid in PVP removal is alkaline hydrolysis. Under alkaline conditions, the γ-lactam ring opens, converting the γ-lactam ring to γ-aminobutyric acid. Because succinimide is more easily hydrolyzed, this hydrolysis can be aided by first oxidizing the γ-lactam to succinimide. Hydrolyzed PVP polymer (fully hydrolyzed can be called polyvinylaminobutyrate) does not exhibit increased biodegradability. Thus, while PVP can be chemically altered, this alteration alone does not appear to aid in PVP removal. Surprisingly, it has been discovered that removal can be aided by using rare earth salts, iron salts, or mixtures thereof.

[0020] Accordingly, the present application relates to a method for removing PVP from a water source using a rare earth salt, an iron salt, or a mixture thereof. The application further relates to a PVP composition formed by this method, the composition comprising: (a) hydrolyzed polyvinylpyrrolidone (h-PVP); and (b) rare earth cations, iron cations, or a mixture thereof, wherein the cations are bound to the h-PVP, and the composition comprises about 1% to about 50% by weight of the cations, based on the total weight of the composition, excluding any water present in the composition. This PVP composition can then be used to treat a water source to remove contaminants selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof.

[0021] Accordingly, the present application further relates to an integrated method for treating water, in which a water source, such as industrial wastewater, is first treated to remove PVP, producing a composition comprising (a) hydrolyzed polyvinylpyrrolidone (h-PVP) and (b) rare earth cations, iron cations, or a mixture thereof, wherein the cations are bound to the h-PVP, and the composition comprises about 1% to about 50% by weight of the cations, based on the total weight of the composition, not considering any water present in the composition. In certain embodiments, the cations are rare earth cations. In other embodiments, the cations are a mixture of rare earth cations and iron cations. This PVP composition is then utilized in a method for removing contaminants from an aqueous stream, the contaminants being selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof.

[0022] How to remove PVP from water In its first embodiment, the present application relates to an effective and efficient method for removing PVP from an aqueous stream, which method uses rare earth cations, iron cations, or a mixture thereof. The method forms a composition comprising (a) hydrolyzed polyvinylpyrrolidone (h-PVP) and (b) cations, the cations being bound to the h-PVP, the composition comprising about 1 wt. % to about 50 wt. % of the cations, based on the total weight of the composition, excluding any water present in the composition. The cations are rare earth cations, iron cations, or a mixture thereof.

[0023] In certain embodiments, the cations are rare earth cations, and the formed composition comprises (a) hydrolyzed polyvinylpyrrolidone (h-PVP) and (b) rare earth cations, where the rare earth cations are bound to the h-PVP, and the composition comprises from about 1% to about 50% by weight of the rare earth cations, based on the total weight of the composition, excluding any water present in the composition. In certain embodiments, the composition comprises from about 10% to about 40% by weight of the cations, based on the total weight of the composition, excluding any water present in the composition.

[0024] In other embodiments, the cations are iron cations and the composition comprises about 1% to about 50% by weight of iron cations, based on the total weight of the composition, not considering any water present in the composition.

[0025] In further embodiments, the cations are a mixture of rare earth and iron cations, and the composition comprises about 1% to about 50% by weight of the cations, based on the total weight of the composition, not considering any water present in the composition. The mixture of cations can be any mixture between 100% rare earth and 100% iron cations, and in certain embodiments, the mixture can be about a 1:1 mixture of rare earth to iron cations (i.e., about 50% rare earth and 50% iron cations).

[0026] Although the methods of the present disclosure are primarily intended for removing PVP from industrial water sources to remove PVP from the aqueous feed and create ion-bound hydrolyzed PVP (h-PVP), it will be understood that the methods can be used to treat any aqueous liquid feed containing undesirable amounts of PVP. Examples of such liquid feeds for these methods include, among others, wastewater, groundwater or surface water, tap water, well water, rainwater, surface water such as water from lakes, ponds, and marshes, agricultural water, and geothermal fluids. In certain embodiments, industrial water containing dissolved undesirable PVP may also contain some amount of dissolved or slurried rare earth cations from other industrial processes.

[0027] This effective and efficient method for removing dissolved PVP from a water source or aqueous stream includes providing an aqueous stream having a first PVP concentration. As described above, this aqueous stream can be an industrial aqueous stream or any aqueous stream containing undesired dissolved PVP. In the method disclosed herein, the aqueous stream is hydrolyzed to provide an aqueous stream containing hydrolyzed PVP (h-PVP). Under alkaline conditions, the γ-lactam ring of PVP opens, converting the γ-lactam ring to γ-aminobutyric acid. Any amounts of rare earth cations that may also be present in the industrial aqueous stream do not associate with the PVP until the PVP is hydrolyzed.

[0028] Polyvinylpyrrolidone (PVP) is a water-soluble polymer made from the monomer N-vinylpyrrolidone. [ka]

[0029] PVP is available in a variety of molecular weights and associated viscosities. Regardless of its molecular weight, PVP is highly soluble in polar solvents such as water, making it difficult to remove and / or precipitate. PVP of all molecular weights can be removed in the method disclosed herein.

[0030] Hydrolysis of PVP produces COO-substituents within the polymer to which cations can be attached. The hydrolysis reaction is as follows: [ka]

[0031] Those skilled in the art understand that the percent hydrolysis of PVP is based on the percent of lactam rings opened to butyric acid substituents. See, e.g., Conix, A. and G. Smets, "Ring Opening in Lactam Polymers," J. Polymer Sci., 1955, Vol. XV, pp. 221-229, and Frank, H.P., "The Lactam-Amino Acid Equilibria for Ethylpyrrolidone and Polyvinylpyrrolidone," J. Polymer Sci., 1954, Vol. XII, pp. 565-576. Those skilled in the art also understand that hydrolysis is determined by the rate equation: Rate = k * [lactam] * [OH - Therefore, one skilled in the art will understand that the % hydrolysis of PVP is dependent on the concentration of lactam (PVP), base (OH - It is understood that the hydrolysis rate can be controlled by varying the concentration of base, temperature, and reaction time. Thus, longer reaction times, higher temperatures, and / or higher concentrations of base result in more hydrolysis, and while 100% hydrolysis is theoretically achievable, the addition of rare earth cations, iron cations, or mixtures thereof is economically costly and unnecessary, given that they are effective in removing PVP even without 100% hydrolysis. Sufficient hydrolysis to allow sufficient cation coordination / binding to precipitate cation-bound h-PVP is the % hydrolysis required for the methods disclosed herein to be effective. Thus, the % hydrolysis must be high enough to allow sufficient cation coordination to precipitate cation-bound h-PVP. This % hydrolysis can be from about 10% to about 75%. In certain embodiments, the % hydrolysis is from about 20% to about 75%.

[0032] Those of skill in the art will understand that % hydrolysis can be measured by conductometric titration using a base such as NaOH and using a Philips GM 4249 conductance meter, as described in Conix, A. and G. Smets, "Ring Opening in Lactam Polymers," J. Polymer Sci., 1955, Vol. XV, pp. 221-229, the contents of which are incorporated herein by reference in their entirety.

[0033] When PVP compositions containing ion-bound h-PVP are utilized in methods for removing contaminants from aqueous streams, a higher cation content is more preferred because the target contaminants absorb / bind the cations.

[0034] Thus, as used herein, "hydrolyzed PVP" refers to PVP that is about 10% to about 75% hydrolyzed. In certain embodiments, "hydrolyzed PVP" refers to PVP that is about 20% to about 75% hydrolyzed. In other embodiments, "hydrolyzed PVP" refers to PVP that is about 40% to about 75% hydrolyzed. The hydrolyzed PVP described herein can include PVP that is greater than about 75% to about 100% hydrolyzed, although this greater degree of hydrolysis is not required.

[0035] The step of hydrolyzing the aqueous stream to provide hydrolyzed PVP (h-PVP) includes the optional step of opening the pyrrolidone ring of the PVP to form polyvinyl aminobutyrate units, thus generating COO-substituents that are then available to react with rare earth cations, iron cations, or mixtures thereof to generate / provide an insoluble composition of cation-bound hydrolyzed PVP (h-PVP).

[0036] In certain embodiments, the step of hydrolyzing an aqueous stream having a first PVP concentration to provide an aqueous stream containing h-PVP includes adding a base to adjust the pH to about 10 to about 14; heating to about 35°C to about 140°C for about 1 hour to about 10 hours; cooling to about 20°C to about 25°C; and, optionally, adding an acid to adjust the pH to about 6 to less than 8. The base used can be, for example, hydroxides or oxides of lithium, sodium, potassium, magnesium, calcium, and mixtures thereof. For example, the base can be 1 M NaOH. When an acid is used to adjust the pH, the acid used can be, for example, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, sulfurous acid, phosphoric acid, acetic acid, citric acid, and mixtures thereof.

[0037] In certain embodiments, the step of hydrolyzing an aqueous stream having a first PVP concentration can include oxidizing the aqueous stream prior to alkaline hydrolysis. This hydrolysis can be aided by first oxidizing the γ-lactam to succinimide, as succinimides are more easily hydrolyzed. The oxidation can be carried out by adding any suitable oxidizing agent, including hydrogen peroxide, ozone, sodium peroxide, or mixtures thereof. Oxidation conditions can include temperatures ranging from about 20°C to about 100°C for about 1 hour to about 4 hours.

[0038] The h-PVP-containing aqueous stream is then contacted with a rare earth salt, an iron salt, or a mixture of a rare earth salt and an iron salt to produce cation-bound h-PVP. The composition comprises about 1% to about 50% by weight of cations, based on the total weight of the composition, excluding any water present in the composition. In certain embodiments, the cations are rare earth cations. In other embodiments, the cations are a mixture of rare earth cations and iron cations. This PVP composition with cations bound to h-PVP is precipitated from the aqueous stream. After precipitation, the method provides a treated aqueous stream having a PVP concentration that is lower than the first PVP concentration.

[0039] The cation-bound h-PVP can be isolated or removed from the treated aqueous stream by standard solid-liquid separation techniques, such as sedimentation and filtration. The precipitated solid (i.e., rare earth and / or iron hydrolyzed PVP) can then be used as an adsorption medium to remove contaminants, such as phosphate, from water. For example, the precipitated solid can be used as a soil amendment or in a filter.

[0040] As disclosed herein, the step of contacting an aqueous stream containing h-PVP with a salt includes treating the aqueous stream with a certain amount of a rare earth salt, an iron salt, or a mixture thereof to provide h-PVP having rare earth cations, iron cations, or a mixture thereof bound to the PVP. This produces an insoluble PVP composition that precipitates from the aqueous stream. Therefore, the method may further include filtering the treated aqueous stream to remove the precipitated hydrolyzed PVP with bound cations. In other embodiments, the method may further include decanting the treated aqueous stream to remove the precipitated hydrolyzed PVP with bound cations.

[0041] An aqueous stream containing h-PVP can be treated by contacting it with a solution or slurry of a rare earth salt, an iron salt, or a mixture thereof. The slurry or solution is in water, and is therefore an aqueous solution or slurry. Optionally, the anion of the salt can also be incorporated into the composition.

[0042] Generally, an aqueous stream containing h-PVP is treated by exposing or contacting the aqueous stream with a solution or slurry containing rare earth or iron cations or a mixture thereof. This solution or slurry containing rare earth or iron cations is formed from a rare earth or iron salt in water. The rare earth or iron salt can be a soluble salt (producing a solution) or an insoluble salt suspended in a liquid (producing a slurry). The soluble salt can be a chloride, sulfate, sulfonate, nitrate, acetate, or a mixture thereof. The insoluble salt can be a carbonate, hydroxide, oxide, or a mixture thereof. The liquid of the solution or slurry is water. In certain embodiments, the salt is a rare earth chloride and is an aqueous solution.

[0043] After contacting an aqueous stream containing h-PVP with a rare earth or iron salt solution or slurry, cations are bound to the h-PVP to provide a cation-bound h-PVP composition that is insoluble in water and, after isolation, can be used to treat water as disclosed herein.

[0044] In certain embodiments, in addition to the rare earth and / or iron cations, the anions of the rare earth and / or iron salts are also incorporated into the PVP composition.

[0045] In these embodiments, the composition further comprises from about 0.5% to about 10% by weight of an anion, based on the total weight of the composition. In certain of these embodiments, the composition further comprises from about 0.5% to about 5% by weight of an anion, based on the total weight of the composition. The weight percent of the anion, based on the total weight of the composition, does not take into account any residual water in the composition.

[0046] In certain embodiments for removing PVP and preparing an h-PVP composition, rare earth salts are used. These rare earth salts can be salts of rare earths selected from the group consisting of cerium, lanthanum, yttrium, and mixtures thereof. In certain embodiments, the rare earth salt is a salt of a rare earth selected from the group consisting of cerium, lanthanum, and mixtures thereof.

[0047] In certain embodiments for removing PVP and preparing the composition, a rare earth chloride solution is used. The solution can be a rare earth chloride selected from CeCl, LaCl, or a mixture of CeCl and LaCl. The ratio of Ce to La in these rare earth chloride salts is further described herein and can be any ratio from about 100% Ce to about 100% La.

[0048] In embodiments in which a rare earth salt is used, the rare earth salt may be a salt of a rare earth selected from the group consisting of cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb), and yttrium (Y), and mixtures thereof. In certain embodiments, the rare earth salt and final cation are light rare earths, including cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), and mixtures thereof.

[0049] In certain embodiments, the rare earth salt is a chloride salt and is a mixture of Ce and La, with the remainder (if present) being chloride salts of other rare earth elements, which may be any one or more of the other rare earth elements, which may be selected from the group consisting of Pr, Nd, Sm, Y, Dy, and mixtures thereof.

[0050] In one embodiment, the rare earth salt may be provided in a hydrated crystalline form (eg, RECl3·xH2O, where x is 1-8).

[0051] In certain embodiments, the rare earth chlorides used to prepare the h-PVP compositions are CeCl3, LaCl3, or mixtures of CeCl3 and LaCl3, all containing less than 2% chloride salts of other rare earth elements based on total rare earths. In certain embodiments, the rare earth chlorides used to prepare the h-PVP compositions are CeCl3, LaCl3, or mixtures of CeCl3 and LaCl3, all containing less than 1% chloride salts of other rare earth elements. These embodiments include any amount of Ce and La ranging from pure CeCl3 to pure LaCl3 and all mixtures of CeCl3 and LaCl3 in between.

[0052] Common impurities found in the rare earth salts utilized herein include sodium, iron, lead, and uranium. In certain embodiments, the rare earth salt solution or slurry contains less than about 10 g / L of these common impurities. The rare earth salt solution or slurry can contain less than about 9 g / L of sodium, less than about 20 mg / L of iron, less than about 3 mg / L of lead, and less than about 1 mg / L of uranium.

[0053] The concentration of the rare earth chloride solution utilized can be from about 0.01 mol / L to about 3.0 mol / L rare earth. In certain embodiments, the concentration of the rare earth chloride solution utilized can be from about 2.0 mol / L to about 3.0 mol / L rare earth.

[0054] The ion-bound hydrolyzed PVP (h-PVP) can be isolated or removed from the treated aqueous stream by standard solid-liquid separation techniques, such as settling and filtration. Accordingly, the method may further comprise filtering the treated aqueous stream to remove the precipitated cation-bound h-PVP. In other embodiments, the method may further comprise settling the precipitated cation-bound h-PVP and decanting the treated aqueous stream. The method provides a treated aqueous stream having a PVP concentration that is lower than the first / initial PVP concentration of the untreated aqueous stream.

[0055] In certain embodiments of these methods, the methods further include drying the composition comprising ion-bound h-PVP. The composition can be dried at a temperature of about 40° C. to about 100° C., more typically about 40° C. to about 75° C., for about 30 minutes to 24 hours, more typically about 1 hour to about 12 hours.

[0056] In certain embodiments of these methods, the methods further include filtering, washing, and drying the resulting solids. The resulting solids are h-PVP with bound ions (e.g., cations), which can then be used to remove contaminants from aqueous streams.

[0057] These PVP compositions may further comprise ions selected from the group consisting of sodium cations, chloride anions, nitrate anions, sulfate anions, sulfonate anions, carbonate anions, hydroxide anions, oxide anions, and mixtures thereof.

[0058] In certain embodiments, the method for removing PVP from an aqueous stream may further include setting a target concentration for PVP in the treated aqueous stream, wherein the treated aqueous stream has a PVP concentration that is less than or equal to the target concentration.

[0059] In certain embodiments, the method for removing PVP from an aqueous stream may further include setting a target concentration for PVP in the treated aqueous stream, monitoring the PVP concentration in the treated stream, and comparing the PVP concentration to the target concentration.

[0060] The process for removing dissolved undesired PVP can be carried out in a batch process or in a continuous system.

[0061] Accordingly, the present application relates to a method for removing polyvinylpyrrolidone (PVP) from an aqueous stream, the method including: (i) providing an aqueous stream having a first PVP concentration; (ii) hydrolyzing the aqueous stream to provide an aqueous stream containing hydrolyzed PVP (h-PVP); (iii) contacting the aqueous stream containing h-PVP with a rare earth salt, an iron salt, or a mixture thereof to precipitate h-PVP having associated therewith rare earth cations, iron cations, or a mixture thereof; and (iv) providing a treated aqueous stream having a PVP concentration that is lower than the first PVP concentration.

[0062] In one embodiment, a rare earth salt is used. Accordingly, a method for removing polyvinylpyrrolidone (PVP) from an aqueous stream includes (i) providing an aqueous stream having a first PVP concentration, (ii) hydrolyzing the aqueous stream to provide an aqueous stream containing h-PVP, (iii) contacting the aqueous stream containing h-PVP with a rare earth salt to precipitate h-PVP in which the rare earth cations are bound to the PVP, and (iv) providing a treated aqueous stream having a PVP concentration that is lower than the first PVP concentration.

[0063] In other embodiments, iron salts are used, and in further embodiments, any mixture of rare earth salts and iron salts is used.

[0064] In certain embodiments, rare earth ions, iron ions, or mixtures thereof may be present in the aqueous stream containing PVP before the PVP is hydrolyzed. These ions may also be derived from industrial waste processes. The PVP does not react with these ions until it is hydrolyzed, at which point it precipitates.

[0065] These methods effectively and efficiently remove PVP from aqueous streams. In some embodiments, the PVP concentration in the treated aqueous stream is about 20% to about 100% lower than the first PVP concentration. In certain embodiments, the PVP concentration in the treated aqueous stream is about 50% to about 100% lower than the first PVP concentration. In other embodiments, the PVP concentration is about 75% to about 100% lower than the first PVP concentration.

[0066] Thus, in some embodiments, about 50% to about 100% of the PVP is removed, and in certain embodiments, about 75% to about 100% of the PVP is removed.

[0067] The present disclosure includes a novel method that combines the hydrolysis of PVP with the addition of a rare earth salt, an iron salt, or a mixture thereof, which provides for removal of the PVP by standard solid-liquid separation techniques such as sedimentation and filtration. To remove PVP from an aqueous feed and produce a composition, the rare earth salt or iron salt can be provided as a solution or slurry that is contacted with water containing h-PVP. Thus, PVP is removed from the aqueous feed, and a composition containing ion-bound h-PVP is also produced.

[0068] Although the disclosed method for removing PVP from an aqueous feed and producing ion-bound h-PVP is primarily intended for removing PVP from industrial water sources, it will be understood that the method can be used to treat any aqueous liquid feed containing undesirable amounts of PVP. Examples of such liquid feeds for this method include, among others, wastewater, groundwater or surface water, tap water, well water, stormwater, surface water such as water from lakes, ponds, and marshes, agricultural water, and geothermal fluids.

[0069] The present application further relates to methods for treating aqueous feeds using these compositions comprising ion-bound h-PVP. The methods for treating aqueous feeds using ion-bound h-PVP disclosed herein may include steps for making these compositions (of ion-bound h-PVP) within an integrated process, as described in more detail below.

[0070] When used to treat aqueous feeds, compositions containing ion-bound h-PVP remove contaminants from the aqueous feed, providing an effluent / treated aqueous stream with reduced contaminant concentrations compared to the untreated feed. The treated stream may have reduced contaminant concentrations that meet or fall below the target concentration. Depending on the structure used therein, the ion-bound h-PVP composition may be renewed after treating contaminated water for a period of time. The use of ion-bound h-PVP compositions allows for effective and efficient treatment of aqueous feeds to remove contaminants. Without being bound by any theory, it is believed that contaminants absorb onto the rare earth and / or iron cations bound to the h-PVP composition, thus preventing the passage of the contaminants. Thus, contact of the contaminants with the cations results in one or more of the contaminants absorbing and / or reacting with the cations.

[0071] Although the disclosed methods for using ion-bound h-PVP compositions are primarily intended for removing contaminants from water, groundwater, or surface water, it will be understood that the methods can be used to treat any aqueous liquid feed containing undesirable amounts of contaminants. Examples of such liquid feeds include, among others, tap water, well water, stormwater, surface water such as water from lakes, ponds, and wetlands, agricultural water, wastewater from industrial processes, surface water, and geothermal fluids.

[0072] FIG. 1 illustrates a general flow diagram for treating water to remove PVP by first hydrolyzing the PVP and then adding a rare earth or iron salt. In method 100, water containing a first PVP concentration is provided (102). The PVP is hydrolyzed by adding a base (104) to raise the pH (to about 10-14) and heating (106) (to about 35° C. to about 140° C. for about 1 hour to about 10 hours). After cooling (to about 20° C. to about 25° C.), an acid is optionally added (108) to adjust the pH to neutral (about 5 to less than about 8). These steps hydrolyze the PVP. The h-PVP-containing aqueous stream is mixed with a rare earth salt to precipitate h-PVP. This provides a treated aqueous stream having a PVP concentration lower than the first PVP concentration.

[0073] Compositions for treating water A method for removing dissolved, undesired PVP produces a composition for treating water. The composition includes: (a) hydrolyzed PVP (h-PVP); and (b) rare earth cations, iron cations, or a mixture thereof, wherein the cations are bound to the h-PVP; the composition includes from about 1% to about 50% by weight of the cations, based on the total weight of the composition. In certain embodiments, the composition includes from about 10% to about 40% by weight of the cations, based on the total weight of the composition. The weight percent of the cations, based on the total weight of the composition, does not take into account any residual water in the composition. In certain of these embodiments, the cations are rare earth cations.

[0074] The composition may further incorporate anions from the salt used to deposit the cations (e.g., rare earth cations). In embodiments further comprising anions, the composition further comprises from about 0.5 wt. % to about 10 wt. % of the anions, based on the total weight of the composition. In certain of these embodiments, the composition comprises from about 0.5 wt. % to about 5 wt. % of the anions, based on the total weight of the composition. The weight percent of the anions, based on the total weight of the composition, does not take into account any residual water in the composition.

[0075] Thus, the present application relates to compositions for treating water, comprising h-PVP having ions bound thereto. These compositions can be used in soil conditioners or filters. The ions are selected from rare earth cations, iron cations, or mixtures thereof. In one embodiment, the ions are rare earth cations. In another embodiment, the ions are iron cations. In yet another embodiment, the ions can be a mixture of rare earth cations and iron cations. This mixture can be any mixture between 100% rare earth cations and 100% iron cations, and in certain embodiments, about 1:1 rare earth cations to iron cations. The ions can also be ions from the solution / slurry used to deposit the rare earth cations and / or iron cations. These ions can include anions of rare earth salts and / or iron salts.

[0076] Thus, the composition comprises h-PVP and ions selected from rare earth cations, iron cations, and mixtures thereof, wherein the ions are bound to the h-PVP. These ions may also include anions of the salts used to deposit the rare earth and / or iron cations. The ions of the composition may further include sodium, chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof.

[0077] Without being bound by any theory, it is believed that contaminants are absorbed by rare earth cations, iron cations, and mixtures thereof. Therefore, these compositions can be used in water treatment and in structures for filtering / capturing contaminated water. These compositions can be used in soil amendments or filters.

[0078] As described herein, h-PVP has ions selected from rare earth cations, iron cations, or mixtures thereof bound to it or associated in some manner with it. The rare earth cations or iron cations can be associated with h-PVP by any type of attractive force, including van der Waals association, covalent bonding, or ionic bonding. Thus, as described herein, h-PVP having rare earth cations or iron cations bound or associated therewith includes both non-bonded attractive forces and chemically bonded ones. In certain embodiments, the cations are linked to the carboxylates (COO) of hydrolyzed PVP through the ionic bonding of the cations. - ) is bound to the PVP. Sufficient cations must be bound / bound to precipitate the PVP and then remove the contaminants.

[0079] As used herein, hydrolyzed means about 10% to about 75% hydrolyzed, in certain embodiments, about 10% to about 75% hydrolyzed, and in certain embodiments, about 40% to about 75% hydrolyzed. As used herein, hydrolyzed can also include greater than about 75% to about 100% hydrolyzed, although this higher degree of hydrolysis is not required. Percent hydrolyzed is a measure of the percent lactam rings that are opened to COO-substituents within the PVP polymer to which rare earth and / or iron cations can be attached.

[0080] In the present composition, the ions bound to the h-PVP are rare earth cations, iron cations, or mixtures thereof. In certain embodiments, the ions are rare earth cations. In other embodiments, the ions are iron cations. In further embodiments, the ions are a mixture of iron cations and rare earth cations.

[0081] The compositions described herein can be powders or particles, or can have any form and / or shape that exposes the maximum amount of ions bound to h-PVP to the contaminants. Thus, the compositions can be in a fixed bed, molded or compressed into pellets, granules and / or beads, or supported on a polymer structure.

[0082] When the ions bound to the h-PVP composition / soil conditioner are rare earth cations, the rare earth cations are deposited on the PVP from rare earth compounds, such as rare earth salts. In certain embodiments, the rare earth compounds are water-soluble or water-insoluble rare earth salts. For example, in certain embodiments, the rare earth salts are water-soluble and include chlorides, nitrates, sulfates, sulfonates, acetates, and mixtures thereof. In other embodiments, the rare earth salts are water-insoluble and include carbonates, hydroxides, oxides, and mixtures thereof. The anions of the salts may also be incorporated into the composition. Thus, the anions of the salts may be incorporated by being bound to the h-PVP and / or by some amount of the anions remaining bound / coordinated to the rare earth cations.

[0083] In these embodiments, the compositions disclosed herein, comprising h-PVP and rare earth cations bound to h-PVP, may further comprise anions of the salt used to deposit the rare earth cations. In certain embodiments, the compositions may further comprise anions selected from the group consisting of chloride, nitrate, sulfate, sulfonate, carbonate, hydroxide, oxide, and mixtures thereof. These anions may be bound to the h-PVP, and / or some amount of the anions may remain bound / coordinated to the rare earth cations. In certain of these embodiments, the compositions further comprise anions selected from the group consisting of chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof. In certain embodiments, the compositions may further comprise sodium ions.

[0084] When the ions bound to the h-PVP composition / soil conditioner are iron cations, the iron cations are deposited on the PVP from an iron compound, such as an iron salt. In certain embodiments, the iron compound is a water-soluble or water-insoluble iron salt. For example, in certain embodiments, the iron salt is water-soluble and includes chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof. In other embodiments, the iron salt is water-insoluble and includes carbonate, hydroxide, oxide, and mixtures thereof. Salt anions can also be incorporated into the composition. Thus, salt anions can be incorporated by also binding to the h-PVP and / or by some amount of the anions remaining bound / coordinated to the iron cations.

[0085] In these embodiments, the compositions disclosed herein, comprising h-PVP and iron cations bound to h-PVP, may further comprise anions of the salt used to deposit the iron cations. In certain embodiments, the compositions may further comprise anions selected from the group consisting of chloride, nitrate, sulfate, sulfonate, carbonate, hydroxide, oxide, and mixtures thereof. These anions may be bound to the h-PVP, and / or some amount of the anions may remain bound / coordinated to the iron cations. In certain of these embodiments, the compositions further comprise anions selected from the group consisting of chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof. In certain embodiments, the compositions may further comprise sodium ions.

[0086] A corresponding composition can also include h-PVP and a mixture of iron and rare earth cations.

[0087] The precipitated solid h-PVP with bound ions can be used as an adsorption medium for removing contaminants, such as phosphate, from water. Thus, the present disclosure addresses the need for removing PVP from water and creates a use for an otherwise discarded product. In certain embodiments, h-PVP has bound rare earth cations and can be used in soil amendments or filters to remove contaminants from water.

[0088] Compositions (i.e., filters / soil amendments) comprised of ion-bound h-PVP can remove contaminants ("target contaminants") from liquid feeds. Target contaminants include phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, etc., and mixtures thereof. In certain embodiments, the contaminants are phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, or mixtures thereof.

[0089] As used herein, perfluoroalkyl substances (PFAS) include compounds such as perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), Nafion Byproduct 2, 6:2 fluorotelomer sulfonate (6:2FTSA), 8:2FTSA, perfluorobutane sulfonate (PFBS), and F-53B. Perfluoroalkyl substances (PFAS) are as described in “A guide to the PFAS found in our environment. Chemical structures and origins of per- and polyfluoroalky substances that are polluting our world,” C&EN:CAS (a division of the American Chemical Society) (2020), https: / / cen.acs.org / sections / pfas.html, the entire contents of which are incorporated by reference.

[0090] The ion-bound h-PVP soil amendment / filter composition is useful for removing contaminants from aqueous streams. As described, the aqueous stream may be one or more of drinking water, stormwater, surface water, and groundwater sources containing undesirable amounts of contaminants. Furthermore, the aqueous stream may include, but is not limited to, well water, surface water (such as water from lakes, ponds, and marshes), agricultural water, wastewater from industrial processes, and geothermal water.

[0091] When the ion is a rare earth (RE) cation, the rare earth cation is a cation of cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb), and yttrium (Y), or a mixture thereof. In certain embodiments, the rare earth cation is a light rare earth cation comprising cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), or a mixture thereof.

[0092] In certain embodiments, the rare earth cation is selected from the group consisting of cerium, lanthanum, yttrium, and mixtures thereof. In other embodiments, the rare earth cation is selected from the group consisting of cerium, lanthanum, and mixtures thereof.

[0093] In certain embodiments, the rare earth cation is Ce, La, or a mixture of Ce and La. In these embodiments, trace amounts (i.e., less than 2 wt. % of the total weight of rare earth cations, and in some embodiments, less than 1 wt. %) of other rare earth cations may be present. In certain embodiments, these other rare earth cations may be one or more of the light rare earth cations. These embodiments include any amount of Ce and La, from pure Ce cations to pure La cations, and all mixtures of Ce and La in between.

[0094] These weight or mole percentages for mixtures of rare earth cations or "pure" rare earth cations are for those rare earth cations relative to other rare earth cations, not for the overall composition.

[0095] In certain embodiments, the rare earth cation is “pure.” As used herein, a “pure” cation is 95 mole percent or more of that rare earth, based on the total moles of all rare earth cations present, with all the remainder being any other rare earth cation.

[0096] For example, pure cerium is 95% or more cerium cations based on the total moles of all rare earth cations in the composition. Pure lanthanum is 95% or more lanthanum cations, pure neodymium is 95% or more neodymium cations, pure yttrium is 95% or more yttrium cations, etc. In some embodiments, a "pure" rare earth cation can be 99% or more of that rare earth based on the total moles of all rare earths present, with all the remainder being other rare earths. For example, the rare earth cation can be 99% or more cerium based on the total moles of all rare earth cations in the composition, or 99% or more lanthanum based on the total moles of all rare earth cations.

[0097] The rare earth cation can be, for example, any mixture of cerium and lanthanum, including from 99.9% cerium and 0.1% lanthanum to 0.1% cerium and 99.9% lanthanum and all mixtures therebetween.

[0098] As noted above, the anion of the rare earth salt used to form the composition may also be incorporated into the composition. When part of the composition, the anion may be bound to the PVP and / or may remain associated / bound with the rare earth cation.

[0099] In certain embodiments of rare earth cation-bound h-PVP, the rare earth cations are a mixture of Ce and La, with 55.0-75.0 wt.% Ce and 25.0-45.0 wt.% La, based on the total weight of the rare earth cations present, and the remainder being other rare earths. In one particular embodiment, the rare earth cations are a mixture of Ce and La, with 55.0-75.0 wt.% Ce and 25.0-45.0 wt.% La, based on the total weight of the rare earths, and the remainder being less than 2 wt.% of other rare earth cations. In one particular embodiment, the remainder being less than 1 wt.% of other rare earth cations, based on the total weight of the rare earths.

[0100] The rare earth cations can be 59.8-70.1 wt% Ce and 29.9-40.1 wt% La, 63.0-69.0 wt% Ce and 30.0-36.0 wt% La, and 64.0-68.0 wt% Ce and 31.0-35.0 wt% La, based on the total weight of rare earth cations present (with or without trace amounts of other rare earth cations). In certain embodiments, the rare earth cations are 59.8-70.1 wt% Ce, 29.9-40.1 wt% La, based on the total weight of rare earth cations present, with the remainder being one or more other rare earth cations, the remainder being less than 1 wt%.

[0101] In a further embodiment, the rare earth cations are 60.0 to 65.5 mole % Ce and 30.0 to 40.0 mole % La, based on the total moles of rare earth cations, with all the remainder being one or more other rare earths.

[0102] Further embodiments include rare earth cations of 59.8-70.1% Ce and 29.9-40.1% La, 63.0-69.0% Ce and 30.0-36.0% La, and 63.0-68.0% Ce and 31.0-35.0% La, based on the total moles of rare earth cations (all with the remainder being one or more other rare earths, all based on the total moles of rare earths). In certain embodiments, the remainder of any other rare earth cation is less than 2% or less than 1%.

[0103] Other rare earth cations that may be present are any one or more of the other rare earths. In certain embodiments, these other rare earth cations may be selected from the group consisting of Pr, Nd, Sm, Y, and mixtures thereof.

[0104] Embodiments including rare earth cations include 25.0-35.0% Ce and 12.0-20.0% La, with the remainder being a mixture of other rare earths, Ce and La. In certain of these embodiments, the remainder of the other rare earth cations is greater than about 45% or about 50% or greater. The remainder can be a single rare earth cation or a mixture of rare earth cations (other than Ce and La). For example, the other rare earth cations can be about 50% Y, or about 50% Sm, or a mixture of about 25% Sm and about 25% Y.

[0105] In certain embodiments, the rare earth cation is Ce, La, or a mixture of Ce and La, all with less than 2% of other rare earths. In certain embodiments, the rare earth cation is Ce, La, or a mixture of Ce and La, all with less than 1% of other rare earths.

[0106] Unless otherwise specified herein, the % of a rare earth cation versus other rare earth cation(s) is the mole % of the rare earth cation relative to the total moles of all rare earth cations in the composition, regardless of the anion (such as chloride or nitrate) if the rare earth remains coordinated with the anion from its salt form. Similarly, when the % of a rare earth cation versus other rare earth cation(s) is specified as a weight %, it is relative to the total weight of all rare earth cations in the composition, regardless of the anion (such as chloride or nitrate) if the rare earth remains coordinated with the anion from its salt form. Common impurities found in the rare earths utilized herein include sodium, iron, lead, and uranium.

[0107] When used to treat contaminated water, the composition can be present in a soil conditioner or filter. Thus, the soil conditioner or filer contains h-PVP and ions (e.g., rare earth cations, iron cations, or mixtures thereof) bound to h-PVP. The composition contains about 1% to about 50% by weight of cations based on the total weight of the composition. In certain embodiments, the composition contains about 10% to about 40% by weight of cations based on the total weight of the composition. In certain embodiments, these cations are rare earth cations. In other embodiments, these cations are iron cations. These weight percentages are based on the total weight of the composition and do not take into account any residual water in the composition. In some embodiments, the composition can be dry or can be dried so that there is no water or minimal water present, while in other embodiments, the composition can contain residual water, including significant amounts of residual water.

[0108] In some embodiments, the composition may further comprise an anion, and the composition comprises about 0.5% to about 10% by weight of the anion based on the total weight of the composition. In certain of these embodiments, the composition comprises about 0.5% to about 5% by weight of the anion based on the total weight of the composition. These weight percentages are based on the total weight of the composition and do not take into account any residual water in the composition. In certain embodiments, the anion is selected from the group consisting of chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof.

[0109] Carboxylate of h-PVP (COO - ) functional groups are available to bond with ions. - The functional group may also bind water.

[0110] In certain embodiments, the composition comprises h-PVP and a rare earth (RE) cation bound thereto, the composition having the formula: RE x (h-PVP) y Cl z or RE x (h-PVP) y (NO3) z where x is about 0.002 to about 1, y is about 1, and z is about 0.0008 to about 2. In certain embodiments, x is about 0.3, y is about 1, and z is about 0.085.

[0111] In the above equation, as x increases, z is considered to increase (approximately linearly with respect to each other) while y is held constant. The highest x:y ratio is approximately 1:1, and the highest x:y:z ratio is approximately 1:1:2. The lowest x:y:z ratio is approximately 0.002:1:0.0008.

[0112] In other embodiments, the composition comprises h-PVP and iron cations bound thereto. In these embodiments, the composition has the formula: Fe x (h-PVP) y Cl z or Fe x (h-PVP)y (NO3) z where x is about 0.002 to about 1, y is about 1, and z is about 0.0008 to about 2. In certain embodiments, x is about 0.4, y is about 1, and z is about 0.015. In chloride embodiments, there is more Fe relative to the h-PVP because chloride is a smaller cation, and the h-PVP can more easily encapsulate Cl, leaving less space for Cl to be incorporated, resulting in less Cl. The highest x:y ratio is about 1:1, and the highest x:y:z ratio is about 1:1:2. The lowest x:y:z ratio is about 0.002:1:0.0008.

[0113] Methods of using the compositions for treating water The present application relates to a method for treating contaminated water with a composition comprising (a) h-PVP and (b) cations selected from rare earth cations, iron cations, or mixtures thereof, wherein the cations are bound to the h-PVP, and the composition comprises about 1% to about 50% by weight of the cations, based on the total weight of the composition. In certain embodiments, the cations are rare earth cations, and in other embodiments, the cations are iron cations. The weight percent of the cations, based on the total weight of the composition, does not take into account any residual water in the composition.

[0114] Without wishing to be bound by any theory, it is believed that contaminants in an aqueous stream are removed by contact with the cations bound to the hydrolyzed PVP of the compositions disclosed herein. It is believed that contacting the contaminants in the aqueous stream with the cations bound to the PVP causes the contaminants to one or more of absorb and / or react with the cations. Thus, by contacting with the compositions described herein, some, most, or all of the contaminants contained in the contaminated aqueous stream are removed from the aqueous stream / feed.

[0115] Use of the compositions disclosed herein to treat contaminated water allows for efficient operation of the water treatment process and provides an effluent / treated stream having reduced concentrations of contaminants compared to the water before treatment.

[0116] A method for removing contaminants from an aqueous stream includes the steps of: (i) contacting an aqueous stream having a first contaminant concentration with a composition comprising (a) h-PVP and (b) cations selected from rare earth cations, iron cations, or mixtures thereof, wherein the cations are bound to the h-PVP, and the composition comprises from about 1% to about 50% by weight of the cations based on the total weight of the composition; (ii) removing the contaminants from the aqueous stream by contacting the aqueous stream with the composition; and (iii) providing an aqueous stream having a second contaminant concentration that is lower than the first contaminant concentration.

[0117] In the methods described herein, the contaminant is selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, and mixtures thereof.

[0118] In some embodiments, the method of treating water to remove contaminants uses a composition having rare earth cations bound to h-PVP, while in other embodiments, a composition having iron cations bound to h-PVP is used.

[0119] In certain embodiments, these methods provide a treated aqueous stream in which the second contaminant concentration is about 50% to about 90% lower than the first contaminant concentration. In some embodiments, the second contaminant concentration is about 50% to about 100% lower than the first contaminant concentration.

[0120] In certain embodiments, these methods remove at least about 50%, or at least about 75%, or at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 99% of the contaminants. In the most efficient embodiments, the contaminants are removed by at least about 90% or more, or to below the detection limit. Thus, in some embodiments, the contaminants can be removed to a level where they are undetectable. The contaminants removed are phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, or mixtures thereof.

[0121] Methods of treating water to remove contaminants may optionally further include one or more of setting a target level for the contaminant to be removed and / or monitoring the treated stream / effluent for the contaminant. These methods may further include replacing or refreshing the composition comprising ion-bound h-PVP after a period of time or after the contaminant level in the treated stream / effluent has increased or generally increased above the set target.

[0122] In certain embodiments, the contaminants to be removed from a water stream are phosphate, phosphorus-containing compounds, and mixtures thereof. Treating water by passing the water through a composition described herein provides a treated stream / effluent having a reduced concentration of phosphorus compared to the water feed. The phosphate and phosphorus-containing compounds are monitored by the concentration of phosphorus in the treated stream. The treated stream can have a phosphorus concentration at or below a target concentration of phosphorus. Thus, the method can further include setting a target concentration of phosphorus and / or monitoring the treated stream / effluent for phosphorus. When removing phosphorus and a composition containing rare earth cations, the composition can be present in an amount to provide a rare earth (RE):phosphorus (P) molar ratio of about 0.1:1 RE:P to about 0.8:1 RE:P.

[0123] In certain embodiments, the contaminant to be removed from the water stream is arsenic, an arsenic-containing compound, or a mixture thereof. Treating water by passing the water through the compositions described herein provides a treated stream / effluent having a reduced concentration of arsenic compared to the water feed. The treated stream can have an arsenic concentration equal to or less than a target arsenic concentration. Thus, the method can further include setting a target arsenic concentration and / or monitoring the treated stream / effluent for arsenic.

[0124] In certain embodiments, the contaminant to be removed from the water stream is PFAS. Treating water by passing the water through the composition described herein provides a treated stream / effluent with a reduced concentration of PFAS compared to the water supply. The treated stream can have a concentration of PFAS that is equal to or less than a target concentration of PFAS. Thus, the method can further include setting a target concentration of PFAS and / or monitoring the treated stream / effluent for PFAS.

[0125] In certain embodiments, the contaminant to be removed from the water stream is fluoride. Treating water by passing the water through the composition described herein provides a treated stream / effluent with a reduced concentration of fluoride compared to the water supply. The treated stream can have a fluoride concentration that is equal to or less than a target concentration of fluoride. Therefore, the method can further include setting a target concentration of fluoride and / or monitoring the treated stream / effluent for fluoride.

[0126] The concentration of the contaminant in the treated stream / effluent after passing through the compositions described herein can be approximately the limit of detection or can be set to the limit of detection (as a target concentration). The concentration of the contaminant after passing through the compositions described herein can also be set to a target concentration based on EPA guidelines, standards, or regulations. The actual (or measured) concentration of the contaminant in the treated stream / effluent after treatment can then be at or below this target concentration.

[0127] The target concentration can also be set as a percentage reduction of the contaminant in the effluent (treated aqueous stream) relative to the concentration in the feed. In certain embodiments, the effluent concentration of the contaminant can be from about 0.5% to about 100% lower than the feed concentrate. In certain embodiments, the effluent concentration of the contaminant is from about 5% to about 50% lower than the feed concentration. In other embodiments, the effluent concentration of the contaminant is from about 10% to about 50% lower than the feed concentration. In other embodiments, the effluent concentration of the contaminant is from about 50% to about 100% lower than the feed concentration.

[0128] In some embodiments, materials containing the compositions described herein can be contained within a structure containing the water treatment composition so that the aqueous feed flows through the structure. The water treatment composition can be contained within smaller structures within the overall structure through which the water flows. If, over time, the effectiveness of the water treatment composition described herein in removing contaminants decreases within the smaller structures, the composition can be replaced or renewed without destroying the overall structure in which it is contained. Thus, the smaller structures containing the ion-bound h-PVP composition can be located near the inlet of the overall structure or near the outlet of the overall structure so that the aqueous feed flows through the smaller structures but the smaller structures can be easily replaced or renewed as needed.

[0129] In these embodiments, the method may further include setting a target concentration for the contaminant, monitoring the concentration of the contaminant in the treated stream, and / or replacing or renewing the h-PVP composition described herein if the concentration of the contaminant increases above (exceeds) the target concentration. In these embodiments, replacing or renewing the composition includes retreatment of the h-PVP with a rare earth and / or iron salt solution / slurry described herein. Thus, the h-PVP is again contacted with the rare earth (or iron) salt in water.

[0130] In some embodiments, a contaminant-containing aqueous stream enters a vessel through an inlet at a temperature and pressure such that the water in the contaminant-containing aqueous stream remains liquid, typically at ambient temperature and pressure. Within the vessel, the contaminant-containing aqueous stream is contacted with a composition described herein. Contacting the composition with the contaminant-containing aqueous stream results in one or more of the contaminants absorbing and / or reacting with the cations, particularly rare earth and / or iron cations, of the h-PVP composition. This removes the contaminants from the aqueous stream.

[0131] In some embodiments, the water treatment compositions described herein can be deposited on a support material, such as polyurethane foam or polyethylene. Furthermore, the water treatment compositions can be deposited on one or more outer and / or inner surfaces of the support material. Those skilled in the art will understand that the inner surface of a support material is generally referred to as the pores. The composition can be supported on the support material with or without a binder. In some embodiments, the composition can be applied to the support material using any conventional technique, such as slurry deposition.

[0132] In some embodiments, the water treatment composition described herein is slurried with a contaminant-containing aqueous stream. It can be understood that the water treatment composition and the contaminant-containing aqueous stream are in contact when they are slurried. Without wishing to be bound by any theory, it is believed that by slurrying and / or contacting the h-PVP composition with the contaminant-containing aqueous stream, some, if not most or all, of the contaminants contained in the aqueous stream are removed from the aqueous stream. After the h-PVP composition is slurried and / or contacted with the contaminant-containing aqueous stream, the slurry is filtered by any known solid-liquid separation method. Optionally, the filtered and treated aqueous stream can be monitored for contaminants. The filtered and treated aqueous stream can have a contaminant concentration at or below a target concentration.

[0133] The methods described herein remove at least a "portion" of the target contaminants. The term "portion" refers to removing between about 10% and about 50% of the contaminants contained in the aqueous stream. More generally, the term "portion" refers to one or more of removing about 10%, about 20%, about 30%, about 40%, or about 50% of the contaminants contained in the aqueous stream.

[0134] In certain embodiments, the methods described herein remove a "majority" of the target contaminants. The term "majority" refers to the removal of greater than about 50% to about 90% of the contaminants contained in the aqueous stream. More generally, the term "majority" refers to the removal of about 60%, about 70%, or about 90% of the contaminants contained in the aqueous stream.

[0135] In certain embodiments, the methods described herein remove "all" of the target contaminants. The term "all" refers to the removal of greater than about 90% to about 100% of the contaminants contained in the aqueous stream. More generally, the term "all" refers to the removal of greater than 98%, 99%, 99.5%, or 99.9% of the contaminants contained in the aqueous stream.

[0136] In certain embodiments, these methods remove at least about 75%, or at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 99% of the contaminants contained in the aqueous solution. In the most efficient embodiments, at least about 95% of the contaminants are removed.

[0137] In some embodiments, the compositions for treating water described herein are in the form of a soil amendment or a filter.

[0138] In some embodiments, the compositions for treating water described herein are in the form of a fixed bed. Furthermore, the fixed bed of the composition is typically comprised of the composition in the form of particles. These particles can have any shape and / or morphology that exposes maximum h-PVP particle surface area to the aqueous liquid and the flow of the aqueous liquid through the bed with minimal backpressure. However, if desired, the h-PVP particles can also be in the form of shaped bodies such as beads, extrudates, porous polymer structures, or monoliths. In some embodiments, the h-PVP compositions described herein can be supported as layers and / or coatings on such bead, extrudate, porous polymer structure, or monolith supports.

[0139] In some embodiments, the h-PVP composition is contained within smaller structures within the overall fixed bed so that it can be removed and renewed / replaced after a period of time as desired or necessary. In these embodiments, the contaminant concentration of the treated stream can be monitored, and the h-PVP composition can be removed and renewed / replaced when the contaminant concentration of the treated stream exceeds a target concentration or begins to measurably increase.

[0140] Contacting the contaminant-containing aqueous stream with the compositions for treating water described herein typically occurs at a temperature of from about 4 to about 100° C., more typically from about 5 to about 40° C. In certain embodiments, contacting occurs at ambient temperature (from about 18 to about 25° C.). Additionally, contacting the composition with the contaminant-containing stream typically occurs at a pH of from about pH 3 to about pH 8.

[0141] Contact of the h-PVP composition with the contaminant-containing aqueous stream typically occurs for a period of greater than about 30 seconds to about 5 days, typically from about 30 seconds to about 24 hours, more typically from about 30 seconds to about 5 hours. Contaminant removal may increase with increasing contact time.

[0142] Treatment of contaminated water with the compositions described herein can be accomplished by passing the contaminated water through the ion-bound h-PVP composition. In doing so, some pressure can be generated to push the water through the h-PVP composition. In other embodiments, the water flows freely through the h-PVP composition.

[0143] Figure 2 illustrates a general flow diagram for using an h-PVP composition to treat water and remove contaminants from an aqueous stream. In method 200, the aqueous stream to be treated is contaminated stormwater and / or surface water (202). The contaminants can be phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, or mixtures thereof. The contaminated aqueous stream is contacted with a composition described herein containing h-PVP having bound cations (204). Contacting the aqueous stream with the composition described herein removes the contaminants from the aqueous stream (206). An aqueous stream having a contaminant concentration lower than the original contaminant concentration is provided (208).

[0144] The method may remove at least about 75%, or at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 99% of the contaminants. In the most efficient embodiments, the contaminants are removed by at least about 90%, or to the limit of detection. In some embodiments, the contaminants may be removed to levels where the contaminants are undetectable.

[0145] The method for treating water may optionally further include one or more of setting a target level of contaminants to be removed from the contaminated aqueous stream in 202 and / or monitoring the provided aqueous stream having reduced contaminant concentrations in 208 for contaminant levels. The method may further include replacing or refreshing the h-PVP composition after a period of time or after the contaminant levels in the treated aqueous stream in 208 begin to increase (or exceed) or generally increase above the set target.

[0146] Integrated Method The present application also relates to an integrated method for removing PVP from water and then using what was originally a waste product to treat aqueous streams to remove other contaminants. Thus, the present disclosure provides an efficient and environmentally friendly method for treating aqueous streams.

[0147] The integrated processes disclosed herein combine a process for removing PVP from an aqueous stream with a process for treating an aqueous stream to remove a contaminant selected from the group consisting of phosphate, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof, using cation-bound h-PVP produced in a first portion of the integrated process to then treat a different aqueous stream in a second portion of the integrated process to remove a contaminant selected from the group consisting of phosphate, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof.

[0148] Thus, an integrated method for removing polyvinylpyrrolidone (PVP) from a first aqueous stream and recycling the removed PVP to remove contaminants from a second aqueous stream includes the steps of: (i) providing a first aqueous stream having a first PVP concentration; (ii) hydrolyzing the first aqueous stream to provide an aqueous stream containing h-PVP; and (iii) contacting the h-PVP-containing aqueous stream with a rare earth salt, an iron salt, or a mixture thereof to precipitate h-PVP having bound cations, wherein the cations are rare earth cations, iron cations, or a mixture thereof. is selected from a mixture thereof; (iv) isolating the precipitated h-PVP having bound cations; (v) contacting a second aqueous stream having a first contaminant concentration with the precipitated h-PVP having bound cations to remove contaminants from the second aqueous stream; and (vi) providing a treated stream having a second contaminant concentration that is less than the first contaminant concentration, wherein the contaminant is selected from the group consisting of phosphate, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluoride, and mixtures thereof.

[0149] Thus, the present disclosure includes a new method that combines the hydrolysis of PVP with the addition of rare earth salts, iron salts, or mixtures thereof, which provides for the removal of PVP by standard solid-liquid separation techniques such as sedimentation and filtration. The precipitated solid (i.e., rare earth and / or iron h-PVP) can then be used as an adsorption medium for removing contaminants such as phosphate from water. Thus, the present disclosure addresses the need for removing PVP from water and also creates a use for an otherwise discarded product.

[0150] In some embodiments, the first aqueous stream containing PVP can be from an industrial water source. However, it is understood that the first aqueous stream containing PVP can be any aqueous liquid feed containing an undesirable amount of PVP. Examples of such aqueous feeds include, among others, wastewater, groundwater or surface water, tap water, well water, rainwater, surface water such as water from lakes, ponds and marshes, agricultural water, and geothermal fluids.

[0151] In some embodiments, the second aqueous feed containing contaminants is groundwater or surface water. However, it will be understood that the second aqueous feed can be any aqueous feed containing undesirable amounts of contaminants. Examples of such aqueous feeds include, among others, tap water, well water, rainwater, surface water such as water from lakes, ponds and marshes, agricultural water, wastewater from industrial processes, surface water and geothermal fluids.

[0152] example The following examples are provided to more fully illustrate the PVP compositions and methods of the present invention, but are in no way intended to limit the scope of the invention thereby.

[0153] In all cases, chemical oxygen demand (COD) was measured by Hach method 8000 and P was measured by Hach method 8048.

[0154] Example 1 An aqueous solution of polyvinylpyrrolidone with an average molecular weight of 40,000 was prepared by dissolving 20 g of this PVP in distilled water and diluting to 1 liter to produce a solution with an effective PVP concentration of 20 g / L. 400 ml of this solution was placed in a 500 ml steel beaker and stirred with a magnetic stir bar. The pH was raised to approximately 12 by adding 10 M NaOH solution. The solution was then heated to 90°C for 9 hours. The volume was maintained by adding distilled water. The solution was then cooled to room temperature, and the pH was adjusted to 6-7.5 with 1 N HCl. Cerium chloride (CeCl3) solution (2.6 mol / L Ce) was then slowly added. A total of 3 ml was added. After stirring for at least 30 minutes, a white precipitate formed. Samples of the starting and final solutions were taken. The samples were filtered through a 0.45 micron filter and analyzed for COD (chemical oxygen demand). The starting solution had a COD of 31,500 mg / L, while the final solution had a COD of 21,000 mg / L, a 33% reduction. COD is a measure of the amount of PVP in a solution, so a 33% reduction in COD indicates that 33% of the PVP was removed from the solution.

[0155] Example 2 400 ml of the remaining starting PVP solution from Example 1 was placed in a 500 ml steel beaker and stirred with a magnetic stir bar. The pH was raised to 13 by adding 10 M NaOH solution. The solution was then heated to 90°C for 9 hours. The volume was maintained by adding distilled water. A jelly-like material formed, similar to that reported in the literature (Conix, A. and G. Smets, "Ring Opening in Lactam Polymers," J. Polymer Sci., 1955, Vol. XV, pp. 221-229). The solution was then cooled to room temperature, and the pH was adjusted to 6-7.5 with 1 N HCl. A sample was taken, filtered through a 0.45 micron filter, and found to have a COD of 7400 mg / L, an effective 76.5% removal by hydrolysis. A total of 3 ml of cerium chloride (CeCl3) solution (2.6 mol / L Ce) was then added. After stirring for at least 30 minutes, a white precipitate formed. The sample was filtered through a 0.45 micron filter and found to have a COD of 800 mg / L, an effective 97.5% removal. COD is a measure of the amount of PVP in solution, so a 76.5% drop in COD indicated that 76.5% of the PVP had been removed by hydrolysis, and further addition of CeCl increased the removal percentage to 97.5%.

[0156] The remaining mixture was then filtered through a 50 micron porosity filter and washed with water. A sample of the solid was dried in an oven at 105°C for 48 hours and found to be 92.7% moisture. This dry solid was then combusted and the remaining ash was CeO2, which accounted for 58.2% of the dry solids and 4.26% of the wet solids.

[0157] Example 3 An aqueous solution of polyvinylpyrrolidone with an average molecular weight of 1.3 million was prepared by dissolving 15 g of this PVP in 15 L of tap water to produce a solution with an effective PVP concentration of 1.5 g / L. 1000 ml of this solution was placed in a 1000 ml glass beaker and stirred with a magnetic stir bar. The pH of the solution was then raised to 11-12 by adding approximately 1 ml of 10 M NaOH. The solution was then heated to approximately 90°C for 3 hours. After cooling, the pH was adjusted to 6-7.5 with 1 N HCl. A sample of the initial solution was analyzed and found to have a COD of 1,820 mg / L. Four aliquots of 20 ml each were taken. One was filtered through a 0.45 micron filter and analyzed for COD. The COD was found to be 1,860 mg / L, representing 0% removal by hydrolysis. The measured value is within the error range of the analytical method, so the difference between 1,860 and 1,820 mg / L is 0.

[0158] Example 3, Part A: To one of the aliquots, 50 μl of a 2.6 mol / L CeCl solution was added. A white precipitate formed. The sample was filtered through a 0.45 micron filter and analyzed for COD. The COD was found to be 1,460 mg / L, a 19.8% reduction.

[0159] Example 3, Part B: Iron chloride (FeCl3) solution (40% FeCl3) was added to the second 20 ml aliquot. A total of 50 μl was added. A reddish precipitate formed. The sample was filtered through a 0.45 micron filter and analyzed for COD. The COD was found to be 1,600 mg / L, a 12% reduction.

[0160] Example 3, Part C: A solution was made by combining 0.5 ml of 2.6 mol / L CeCl3 with 0.5 ml of 40% FeCl3. To one of the aliquots, 50 μl of this solution was added. A reddish precipitate formed. The sample was filtered through a 0.45 micron filter and analyzed for COD. The COD was found to be 1,400 mg / L, a 23% reduction.

[0161] Example 4 An aqueous solution of polyvinylpyrrolidone with an average molecular weight of 40,000 was prepared by dissolving 20 g of this PVP in distilled water and diluting to 1 liter to produce a solution with an effective PVP concentration of 20 g / L. A sample of this solution was analyzed and found to have a COD of 43,320 mg / L. 400 ml of this solution was placed in a 500 ml round-bottom flask equipped with a chiller and stirred with a magnetic stir bar. Ozone was then bubbled through the solution for 5 hours using an ozone generator producing a total of 5,000 mg at 1,000 mg / hour. The pH of the solution was then raised to 13 by adding 10 M NaOH. The solution was then heated to 90°C for 3 hours. After cooling, the pH was adjusted to 6-7.5 using 1 N HCl. The solution was then divided into equal portions of approximately 100 ml. Samples were also taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 33,520 mg / L, a reduction of 22.6%.

[0162] Example 4, Part A: To one of the 100 ml portions, 1 ml of a 2.6 mol / L CeCl solution was added. After stirring for at least 30 minutes, a white precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 26,800 mg / L, a 38.1% reduction.

[0163] Example 4, Part B: Iron chloride (FeCl3) solution (40% FeCl3) was added to the second 100 ml portion. A total of 1 ml was added. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 26,120 mg / L, a 39.7% reduction.

[0164] Example 4, Part C: To one of the 100 ml portions was added a mixture of 0.5 ml of 2.6 mol / L CeCl3 solution and 0.5 ml of 40% FeCl3 solution. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 25,680 mg / L, a 40.7% reduction.

[0165] Example 5 An aqueous solution of polyvinylpyrrolidone with an average molecular weight of 40,000 was prepared by dissolving 20 g of this PVP in distilled water and diluting to 1 liter to produce a solution with an effective PVP concentration of 20 g / L. The COD was measured to be 37,440 mg / L. 400 ml of this solution was placed in a 500 ml round-bottom flask equipped with a condenser and stirred with a magnetic stir bar. 10 ml of 30% hydrogen peroxide (H2O2) was added. The pH of the solution was then raised to 13 by adding 10 M NaOH. The solution was then heated to 90°C for 6 hours. After cooling, the pH was adjusted to 6-7.5 using 1N HCl. The solution was then divided into equal portions of approximately 100 ml. A sample was also taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 35,400 mg / L, a 0.4% reduction.

[0166] Example 5, Part A: To one of the 100 ml portions, 1 ml of the 2.6 mol / L CeCl solution was added. After stirring for at least 30 minutes, a white precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 35,200 mg / L, a 1.0% reduction.

[0167] Example 5, Part B: Iron chloride (FeCl3) solution (40% FeCl3) was added to the second 100 ml portion. A total of 1 ml was added. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 32,400 mg / L, an 8.9% reduction.

[0168] Example 5, Part C: To one of the 100 ml portions, a mixture of 0.5 ml of 2.6 mol / L CeCl3 solution and 0.5 ml of 40% FeCl3 solution was added. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 29,000 mg / L, a reduction of 18.4%.

[0169] Example 6 An aqueous solution of polyvinylpyrrolidone with an average molecular weight of 1,300,000 was prepared by dissolving 20 g of this PVP in distilled water and diluting to 1 liter to produce a solution with an effective PVP concentration of 20 g / L. A sample was analyzed and found to have a COD of 45,960 mg / L. 400 ml of this solution was placed in a 500 ml round-bottom flask equipped with a refrigerator and stirred with a magnetic stir bar. The pH of the solution was then raised to 13 by adding 10 M NaOH. The solution was then heated to 90°C for 6 hours. After cooling, the pH was adjusted to 6-7.5 using 1 N HCl. The solution was then divided into equal portions of approximately 100 ml. A sample was also taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 43,240 mg / L, a 5.9% reduction.

[0170] Example 6, Part A: To one of the 100 ml portions, 1 ml of 2.6 mol / L CeCl3 solution was added. After stirring for at least 30 minutes, a white precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 2,120 mg / L, a 95.4% reduction.

[0171] Example 6, Part B: Iron chloride (FeCl3) solution (40% FeCl3) was added to the second 100 ml portion. A total of 1 ml was added. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 1,810 mg / L, a 96.1% reduction.

[0172] Example 6, Part C: To one of the 100 ml portions was added a mixture of 0.5 ml of 2.6 mol / L CeCl3 solution and 0.5 ml of 40% FeCl3 solution. After stirring for at least 30 minutes, a reddish precipitate formed. A sample was taken, filtered through a 0.45 micron filter, and analyzed for COD. The COD was found to be 1,310 mg / L, a 97.1% reduction.

[0173] Example 7 The following experiment was conducted to test the phosphorus removal capacity of the precipitate composition from Example 2. Two solutions, 5 liters each, were prepared using DI water and monobasic sodium phosphate with target concentrations of 3 and 5 mg / L P. Each solution was divided into five 1 L containers. Approximately 100, 200, 300, and 400 mg of the precipitate from Example 2 were added to four of these containers. The fifth container served as a control. The containers were then placed in a tumbler and allowed to rotate for 24 hours. Samples of the solution were then filtered through a 0.45 micron syringe filter and analyzed for P using Hach Method 10080, reported in mg / L P. The difference between the control and test solutions was calculated as the amount of P bound to the solids. This number was multiplied by the solution volume and divided by the solids weight to give the calculated binding capacity, given in mg / g. The results for each material are shown in the table below. The results are also plotted in Figure 3, with the final P concentration in mg / LP plotted on the horizontal axis and the binding capacity in mg P per gram of solid on the vertical axis. The results are plotted this way because they graphically display the distribution of contaminant (P) between the amount adsorbed on the solid and the amount remaining in solution at equilibrium. Better adsorbing materials not only have higher binding capacities, but also have larger slopes at lower concentrations, with a slope approaching zero at the concentration where maximum binding capacity is reached. [Table 1]

[0174] 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 appended claims are approximations that may vary depending upon the desired properties sought to be obtained.

[0175] 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.

[0176] It will be apparent that the compositions and methods described herein are well adapted to attain 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 numerous ways and are therefore not limited by the illustrative embodiments and examples set forth above. In this regard, any number of features of the different embodiments described herein may be combined into one single embodiment, and alternative embodiments having fewer or more than all of the features described herein are possible.

[0177] While various embodiments have been described for purposes of this disclosure, various changes and modifications may be made that are well within the scope 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. 1. A method for removing polyvinylpyrrolidone (PVP) from an aqueous stream, comprising: (i) providing an aqueous stream having a first PVP concentration; (ii) hydrolyzing the aqueous stream to provide an aqueous stream containing hydrolyzed PVP (h-PVP); (iii) contacting the aqueous stream containing h-PVP with a rare earth salt to precipitate h-PVP having associated rare earth cations; and (iv) providing a treated aqueous stream having a PVP concentration less than said first PVP concentration. A method comprising:

2. 10. The method of claim 1, further comprising filtering the treated aqueous stream to remove the precipitated h-PVP having bound rare earth cations.

3. 10. The method of claim 1, further comprising decanting the treated aqueous stream to remove the precipitated h-PVP having bound rare earth cations.

4. 10. The method of claim 1, wherein the hydrolysis of the aqueous stream comprises adding a base to adjust the pH to about 10 to about 14, heating to about 35° C. to about 140° C. for about 1 hour to about 10 hours, cooling to about 20° C. to about 25° C., and optionally adding an acid to adjust the pH to about 6 to less than 8.

5. 5. The method of claim 4, wherein said hydrolyzing said aqueous stream further comprises oxidizing said aqueous stream prior to adding said base.

6. 6. The method of claim 5, wherein said oxidizing comprises adding hydrogen peroxide, ozone, or a mixture thereof.

7. 2. The method of claim 1, wherein the rare earth salt is a salt of a rare earth selected from the group consisting of cerium, lanthanum, yttrium, and mixtures thereof.

8. 10. The method of claim 1 or 7, wherein the rare earth salt is selected from the group consisting of chlorides, sulfates, sulfonates, nitrates, acetates, and mixtures thereof.

9. 10. The method of claim 1, wherein the PVP concentration in the treated aqueous stream is about 50% to about 100% lower than the first PVP concentration.

10. 10. The method of claim 1, further comprising the step of setting a target concentration for PVP in the treated aqueous stream, wherein the treated aqueous stream has a PVP concentration less than or equal to the target concentration.

11. 10. The method of claim 1, further comprising: setting a target concentration for the PVP in the treated aqueous stream; monitoring the PVP concentration in the treated stream; and comparing the PVP concentration to the target concentration.

12. 1. A composition for treating water, comprising: (a) hydrolyzed polyvinylpyrrolidone (h-PVP); and (b) rare earth cations, wherein the cations are bound to the h-PVP, and the composition comprises from about 1 wt. % to about 50 wt. % of the rare earth cations, based on the total weight of the composition, not considering any water present in the composition.

13. 13. The composition of claim 12, wherein the h-PVP is about 20% to about 75% hydrolyzed.

14. 13. The composition of claim 12, wherein the rare earth cation is a cation selected from the group consisting of cerium, lanthanum, yttrium, and mixtures thereof.

15. 13. The composition of claim 12, further comprising an anion selected from the group consisting of chloride, nitrate, sulfate, sulfonate, acetate, and mixtures thereof.

16. 16. The composition of claim 15, wherein the composition comprises from about 0.5% to about 10% by weight of anion, based on the total weight of the composition not considering any water present in the composition.

17. 13. The composition of claim 12, wherein the rare earth cation is Ce, La, or a mixture of Ce and La.

18. 13. The composition of claim 12, wherein the composition comprises from about 10% to about 40% rare earth cations based on the total weight of the composition, not considering any water present in the composition.

19. 1. A method for removing contaminants from an aqueous stream, comprising: (i) contacting an aqueous stream having a first contaminant concentration with a composition for treating water, the composition comprising: (a) hydrolyzed polyvinylpyrrolidone (h-PVP); and (b) rare earth cations, the cations being bound to the h-PVP, the composition comprising from about 1 wt. % to about 50 wt. % rare earth cations, based on the total weight of the composition, not considering any water present in the composition; (ii) removing contaminants from the aqueous stream by contacting the aqueous stream with the composition; and (iii) providing a treated aqueous stream having a second contaminant concentration that is less than the first contaminant concentration. Including, The method wherein said contaminants are selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, and mixtures thereof.

20. 20. The method of claim 19, wherein the composition comprises from about 10 wt. % to about 40 wt. % rare earth cations, based on the total weight of the composition, not considering any water present in the composition.

21. 20. The method of claim 19, wherein the rare earth cation is Ce, La, or a mixture of Ce and La.

22. 20. The method of claim 19, wherein the aqueous stream is stormwater or surface water.

23. 20. The method of claim 19, wherein the second contaminant concentration is about 50% to about 90% lower than the first contaminant concentration.

24. 20. The method of claim 19, further comprising setting a target concentration for the contaminant in the treated aqueous stream, wherein the second contaminant concentration is less than or equal to the target concentration.

25. 20. The method of claim 19, further comprising: setting a target concentration for the contaminant in the treated aqueous stream; monitoring the concentration of the second contaminant and comparing the concentration of the second contaminant to the target concentration; and replacing the composition if the concentration of the second contaminant in the treated aqueous stream exceeds the target concentration.

26. 1. An integrated process for removing polyvinylpyrrolidone (PVP) from industrial aqueous streams and reusing the removed PVP composition to remove contaminants from wastewater, comprising: (i) providing an industrial aqueous stream having a first PVP concentration; (ii) hydrolyzing the industrial aqueous stream to provide an aqueous stream containing hydrolyzed PVP (h-PVP); (iii) contacting the aqueous stream containing h-PVP with a rare earth salt to precipitate h-PVP having associated rare earth cations; and (iv) isolating the precipitated h-PVP having bound rare earth cations; (v) contacting a wastewater stream having a first contaminant concentration with the precipitated h-PVP having rare earth cations bound thereto to remove contaminants from the wastewater stream; and (vi) providing a treated stream having a second contaminant concentration that is less than the first contaminant concentration; Including, The method wherein said contaminants are selected from the group consisting of phosphates, phosphorus-containing compounds, arsenic, arsenic-containing compounds, PFAS, fluorides, and mixtures thereof.

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