Adsorbents for copper, iron and nitrogen treatment and their preparation methods

Abstract

This invention relates to a carbonaceous material activated to form precursor activated carbon, said carbonaceous material being further enhanced by doping with copper, iron, and nitrogen and calcining. The carbonaceous material includes those obtained from coal, wood, or coconut shells. The invention describes a method for doping said activated carbon. This treatment method produces an adsorbent material that exhibits excellent performance in removing chloramines and similar compounds from fluids such as drinking water.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 072,544, filed August 31, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Fluids such as water are typically disinfected by adding oxidizing compounds, irradiating water with ultraviolet radiation, or both. While these techniques are effective in disinfecting water, disinfected water often contains the oxidizing compounds themselves, products of the oxidizing compounds when dissolved in water, or reactive compounds produced by the radiation of water containing various constituent compounds. In short, these various compounds include chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide. These compounds are undesirable because they alter the odor and taste of water, cause health problems, and can cause corrosion of main pipes and service pipes.

[0004] Adsorbents have been used to remove these compounds. Adsorbents absorb and adsorb a variety of compounds. In particular, the pores of the adsorbent allow for the adsorption of compounds. However, pure adsorbents are inefficient and only adsorb a portion of the compounds that must be removed. To improve their effectiveness, adsorbents are sometimes treated with compounds to form catalytic adsorbents. Catalysts are typically present on the surface of the adsorbent particles and function by catalyzing the chemical decomposition of unwanted compounds that are poorly adsorbed or absorbed on the adsorbent. By employing both adsorption and catalysis mechanisms, catalytic adsorbents are significantly more effective than pure, untreated adsorbents. Catalytic adsorbents have been shown to effectively remove chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide from water and other fluids. Even so, improvements are still needed in the individual steps of forming such catalytic adsorbents, and thus in improving the overall adsorbent performance. Summary of the Invention

[0005] A carbon-containing material activated to form precursor activated carbon, the carbon-containing material being further enhanced by doping with iron and copper, as well as nitrogen, and then calcining. The resulting adsorbent material exhibits excellent catalytic performance suitable for use in fluid purification.

[0006] An adsorbent material exists, the adsorbent material being formed from a carbon-containing material that is activated to form precursor activated carbon, the adsorbent material comprising about 2% to about 20% by weight of nitrogen, measured based on dry precursor activated carbon; about 0.1% to about 4% by weight of iron and copper, measured based on dry precursor activated carbon; wherein the chloramine destruction value (CDN) of the adsorbent material is about 5 to about 75.

[0007] In another implementation, the chloramine destruction value is approximately 20 to approximately 75.

[0008] In another embodiment, the peroxide value of the adsorbent material is less than about 20 minutes.

[0009] In another embodiment, the peroxide value of the adsorbent material is from about 1 minute to about 10 minutes.

[0010] In another embodiment, the amount of nitrogen is from about 2.5% by weight to about 5% by weight.

[0011] In another embodiment, the amount of nitrogen is from about 1.4% by weight to about 3.0% by weight.

[0012] In another embodiment, the adsorbent material is formed of a carbon-containing material, which is formed from one or more of coal, wood, and coconut.

[0013] In another embodiment, the carbon-containing material is at least partially formed from coconut.

[0014] In another embodiment, the weight ratio of iron to copper is from about 25:75 to about 75:25.

[0015] In another embodiment, the weight ratio of iron to copper is approximately 50:50.

[0016] In one embodiment, there is a method for manufacturing an adsorbent material, the method comprising: providing a carbon-containing material; activating the carbon-containing material to form precursor activated carbon; optionally oxidizing the precursor activated carbon; doping the precursor activated carbon by contacting it with one or more compounds serving as an iron source, an iron source, and a nitrogen source, thereby forming a doped precursor activated carbon; and calcining the doped precursor activated carbon in a calcining atmosphere to a temperature of at least about 950°C, thereby forming the adsorbent material, wherein the calcining atmosphere does not cause any substantial oxidation or activation of the doped precursor activated carbon.

[0017] In another implementation, the single compound is a copper source, an iron source, and a nitrogen source.

[0018] In another embodiment, the first compound is a copper source and an iron source, and the second compound is a nitrogen source.

[0019] In another embodiment, the first compound is a copper source and a nitrogen source, and the second compound is an iron source.

[0020] In another embodiment, the first compound is an iron source and a nitrogen source, and the second compound is a copper source.

[0021] In another embodiment, the first compound is a copper source, the second compound is an iron source, and the third compound is a nitrogen source.

[0022] In another embodiment, the doped precursor activated carbon is carried out in a single-stage process, which includes contacting the precursor activated carbon in an aqueous solution containing a copper source, an iron source, and a nitrogen source.

[0023] In another embodiment, the copper source is one or more of the following: copper(II) sulfate pentahydrate (CuSO4·5H2O), copper(II) chloride (CuCl2), copper(II) chloride dihydrate (CuCl2·2H2O), copper(II) nitrate (Cu(NO3)2), copper(II) nitrate monohydrate (Cu(NO3)2·H2O), copper(II) sesquihydrate (Cu(NO3)2·1.5H2O), copper(II) hemipentahydrate (Cu(NO3)2·2.5H2O), copper(II) nitrate trihydrate (Cu(NO3)2·3H2O), copper(II) nitrate hexahydrate ([Cu(H2O)6](NO3)2), copper(II) acetate (Cu(CH3COO)2), copper(II) acetate monohydrate (Cu(CH3COO)2H2O), copper(II) formate, Cu(NH3)6 +2 Basic copper carbonate (II)Cu2(OH)2CO3, their compounds, or mixtures thereof; the iron source is one or more of the following: ferric chloride (III) hexahydrate (FeCl3·6H2O), ferric chloride (II) tetrahydrate (FeCl2·4H2O), ferric sulfate (III) ammonium dodecahydrate (NH4Fe(SO4)·12H2O), ferric sulfate (II) heptahydrate (Fe2SO4·7H2O), ferric oxalate (III) ammonium trihydrate ((NH4)3Fe(C2O4)3·3H2O), ammonium hexacyanoferrate (II) hydrate ((NH4)4[Fe(CN)6]·xH2O), ferric citrate. (III) Ammonium ((NH4)5[Fe(C6H4O7)2]), sodium ferrocyanide decahydrate (Na4Fe(CN)6·10H2O), sodium ferrooxate (Na3Fe(C2O4)3), potassium ferrocyanide trihydrate (K4[Fe(CN)6]·3H2O), potassium ferricyanide (K3[Fe(CN)6]), potassium ferrooxate (K2[Fe(C2O4)2]), or ferrous acetate (II) tetrahydrate ((CH3COO)2Fe·4H2O), ferrous lactate dihydrate, ferrous lactate trihydrate, compounds thereof, or mixtures thereof; and the nitrogen source is one or more compounds in which nitrogen has a -3 oxidation state.

[0024] In another embodiment, calcination is carried out in a N2 atmosphere at a temperature of about 800°C to about 1050°C.

[0025] In another implementation, oxidation is required.

[0026] In another implementation, oxidation is not performed.

[0027] In another embodiment, the copper source is copper(II) sulfate pentahydrate (CuSO4·5H2O), the iron source is ferric(III) chloride hexahydrate (FeCl3·6H2O), and the nitrogen source is one or more of urea or dicyandiamide (DCD).

[0028] In another embodiment, calcination is carried out in a N2 atmosphere at a temperature of about 400°C to about 1050°C.

[0029] In another embodiment, calcination is carried out in a N2 atmosphere at a temperature of about 925°C to about 975°C.

[0030] In another embodiment, there is a method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, the method comprising: providing an adsorbent material formed of a carbon-containing material, the carbon-containing material being activated to form precursor activated carbon, the adsorbent material comprising about 2% to about 20% by weight of nitrogen, about 0.1% to about 4% by weight of iron and copper, measured based on dry precursor activated carbon, and wherein the chloramine destruction value (CDN) of the adsorbent material is about 5 to about 75; and contacting the adsorbent material with a fluid.

[0031] In another implementation, the fluid is liquid water.

[0032] In another implementation, the water or adsorbent material has previously undergone a disinfection process. Attached Figure Description

[0033] The aspects, features, benefits, and advantages of the embodiments described herein will become apparent from the following description, the appended claims, and the accompanying drawings, wherein:

[0034] Figure 1 The process according to one implementation scheme is described.

[0035] Figure 2 The process according to one implementation scheme is described.

[0036] Figure 3 The process according to one implementation scheme is described.

[0037] Figure 4 The relationships between OLC, CDN, and peroxide value and different nitrogen contents for Cu-Fe-N doped OLC are depicted.

[0038] Figure 5The relationship between CDN and added metal loading for oxidized OLC is depicted.

[0039] Figure 6 The relationship between peroxide value and added metal load for oxidized OLC is depicted.

[0040] Figure 7 The relationship between CDN and added nitrogen content in Cu-N, Fe-N, or Cu-Fe-N doped oxidized OLCs was depicted.

[0041] Figure 8 The relationships between unoxidized OLC, CDN, and peroxide value for Cu-Fe-N doped OLC and different nitrogen contents are depicted.

[0042] Figure 9 The relationship between CDN and added metal loading for unoxidized OLC is depicted.

[0043] Figure 10 The relationship between peroxide value and added metal load for unoxidized OLC was depicted. Detailed Implementation

[0044] This disclosure is not limited to the specific systems, apparatus, and methods described, as these can vary. The terminology used in the specification is merely for describing particular versions or embodiments and is not intended to limit the scope of the invention. Furthermore, as stated herein, any list of patent documents such as U.S. patents, U.S. patent application publications, WIPO publications, or foreign patent application publications is intended to be incorporated herein by reference in its entirety.

[0045] As used herein, the singular forms “a / an” and “described” include plural references unless the context clearly indicates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Nothing in this disclosure should be construed as an admission that the embodiments described herein are not entitled to any prior art as a result of prior inventions. As used herein, the term “comprising” means “including, but not limited to”.

[0046] As used in this article, the term “about” means adding or subtracting 10% of the value of the number used with it. Therefore, about 50% means in the range of 45% to 55%.

[0047] As used herein, the term "adsorbent material" refers to any material that exhibits adsorption properties, absorption properties, or a combination of adsorption and absorption properties. Adsorption properties refer to the physical adhesion of atoms, ions, or molecules to the surface of a material. Absorption properties refer to the entry of atoms, ions, or molecules into the bulk phase of a material and their retention therein. As examples, adsorbent materials include activated carbon, regenerated carbon, natural and synthetic zeolites, silica, silica gel, alumina, zirconium oxide, and diatomaceous earth. As used herein, "adsorbent material" is a material whose constituent components are essentially adsorbents and / or absorbents, with only a minimum amount of components that are not non-adsorbents and / or absorbents (e.g., the minimum amount of binder required for activated carbon granules to maintain their shape).

[0048] As used herein, the term "adsorbent" refers to any composition or composite material that includes an adsorbent material in a blend, mixture, composite material, or compound having one or more additional materials that do not exhibit adsorbent properties. As an example, one embodiment of an adsorbent includes an activated carbon adsorbent material mixed with a thermally conductive filler.

[0049] As used herein, the term "carbon-containing material" refers to a material containing carbon that has not been thermally or chemically activated. Carbon-containing materials can be mechanically, thermally, or chemically treated, and may even possess weak adsorption properties; however, they do not adsorb large amounts of compounds as expected from materials such as activated carbon. Examples of carbon-containing materials include, but are not limited to, bituminous coal, sub-bituminous coal, lignite, anthracite, wood, wood chips, sawdust, peat, nut shells, fruit pits, coconut shells, babassu nuts, macadamia nuts, dende nut, peach pits, cherry pits, olive pits, walnut shells, wood, lignin, polymers, nitrogen-containing polymers, resins, petroleum asphalt, bagasse, rice husks, corn husks, wheat husks and bran, graphene, carbon nanotubes, or polymer fibers.

[0050] As used herein, the term "disinfection byproduct" refers to compounds formed due to chemical reactions between organic and inorganic substances present in water and the chemical compounds used in the disinfection process, or compounds formed due to ultraviolet radiation irradiation of organic and inorganic substances present in water. Examples of disinfection byproducts include one or more of chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide. However, it should be noted that compounds that are disinfection byproducts may be present in water that has not undergone disinfection.

[0051] As used in this article, the term "macropore" refers to pores in an adsorbent with a diameter greater than approximately 50 nm.

[0052] As used in this article, the term "mesopore" refers to pores in an adsorbent with a diameter of about 2 nm to about 50 nm.

[0053] As used in this article, the term "micropore" refers to pores in an adsorbent with a diameter of less than about 2 nm.

[0054] As used in this article, "chloramine" refers to one or more of monochloramine (NH2Cl), dichloramine (NHCl2), or trichloramine (NCl3).

[0055] The adsorbents or adsorbent materials described herein can be used to remove chloroform and other similar volatile organic compounds (VOCs) from fluids such as water. VOCs are not limited and include one or more of the following: styrene, metolachlor, atrazine, benzene, carbafuran, carbon tetrachloride, chlorobenzene, chloropicrin, 2,4-dichlorophenoxyacetic acid (2,4-D), dibromochloropropane (DBCP), o-dichlorobenzene, p-dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,2-dichloropropane, cis-1,3-dichloropropene, dichlorophenol, isodrin, ethylbenzene, dibromoethane (EDB), and haloacetonitrile (HAN) (including bromochloroacetonitrile, dibromoacetonitrile, dichloroacetonitrile, and trichloroacetonitrile). Nitriles), halogenated ketones (HK) (including 1,1-dichloro-2-propanone and 1,1,1-trichloro-2-propanone), heptachlor (H-34, Heptox), heptachlor epoxide, hexachlorobutadiene, hexachlorocyclopentadiene, lindane, methoxyDDDT, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-TP (silvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, trihalomethanes (including chloroform, bromoform, bromodichloromethane, monochlorodibromomethane, or xylene). VOCs related to the drinking water sector are known in industry and are described, for example, in NSF / ANSI 53-2019, which was designated as a standard on 6 May 2019, the entire contents of which are incorporated herein by reference. In some cases, the removal of VOCs by the adsorbent or adsorbent material is measured by the removal of the VOC substance itself. In other embodiments, the removal of VOCs by the adsorbent or adsorbent material is measured by the removal of substituted compounds. Substitutes are compounds that are chemically similar to the analyte of interest and are present in the sample prior to preparation and analysis. Chloroform is an example of a substituted compound in this paragraph.

[0056] The adsorbents or adsorbent materials described herein can also be used to remove other contaminants, such as perfluoroalkyl and polyfluoroalkyl substances (PFAS), from water or other fluids. PFAS compounds include one or more of the following: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and compounds produced by the GENX process, such as 2,3,3,3,-tetrafluoro-2-(heptafluoropropoxy)propionate and heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether.

[0057] Adsorbents or adsorbent materials can also be used to remove a variety of emerging contaminants from water or other fluids. Such emerging contaminants include one or more of the following: metolachlor, phenytoin, atenolol, carbamazepine, tri(2-chloroethyl) phosphate (TCEP), tri(1-chloro-2-propyl) phosphate (TCPP), N,N-diethyl-m-toluamide (DEET), metolachlor, trimethoprim, ibuprofen, naproxen, estrone, bisphenol A, linuron, or nonylphenol.

[0058] Figure 1 One embodiment of the entire process 10 of this disclosure is shown. Figure 1 In this process, 20% of a carbon-containing material is provided, followed by activation of 30% of the carbon-containing material to form precursor activated carbon. The precursor activated carbon is optionally oxidized 40%, meaning that oxidation 40 is performed in some embodiments but not in others. After oxidation 40, the precursor activated carbon is doped 50, which imparts a certain amount of copper, iron, and nitrogen dopant to the precursor activated carbon, thereby producing doped precursor activated carbon. The doped precursor activated carbon is then calcined 60% by heating at a specific temperature and under a specific atmosphere, and cooled 70% under an inert atmosphere so as not to substantially alter the pore structure or cause any substantial oxidation or activation of the doped precursor activated carbon. The completion of calcination 60% and cooling 70% yields the adsorbent material of this disclosure.

[0059] Carbon material processing

[0060] This disclosure provides one or more carbon-containing materials as precursors to the final adsorbent. The carbon-containing materials may be mechanically, thermally, or chemically treated, and may even possess weak adsorption properties; however, they will not adsorb large amounts of compounds as expected from materials such as activated carbon. Furthermore, although the carbon-containing materials may have undergone mechanical, thermal, or chemical treatment, they have not been treated in a manner consistent with activated carbon. Examples of carbon-containing materials include, but are not limited to, bituminous coal, sub-bituminous coal, lignite, anthracite, wood, wood chips, sawdust, peat, nut shells, fruit pits, coconut shells, babassu nuts, macadamia nuts, dende nut, peach pits, cherry pits, olive pits, walnut shells, wood, lignin, polymers, nitrogen-containing polymers, resins, petroleum asphalt, bagasse, rice husks, corn husks, wheat husks and bran, graphene, carbon nanotubes, or polymer fibers.

[0061] In some implementations, the carbon-containing material is coconut. Coconut carbon-containing materials are particularly useful because when coconut is activated to form activated carbon, it has excellent adsorption properties for chloroform and other organic compounds.

[0062] After the carbon-containing material is provided, it is processed. Certain processing steps are not limited. These steps are not limited and depend on the type of carbon-containing material and the desired form of the final activated carbon, and include one or more of the following steps: pyrolyzing the carbon-containing material to form charcoal, pulverizing the charcoal, mixing a binder with the pulverized charcoal, pressing the pulverized charcoal and binder into briquettes, pulverizing the briquettes, grading the pulverized briquettes, and baking the graded briquettes or the briquettes themselves to carbonize, cure, or remove the binder. However, in all cases, the carbon-containing material in the form of baked briquettes or graded granules is thermally activated, chemically activated, or thermally and chemically activated. Thermal activation is carried out by heating the baked briquettes or graded granules in the presence of one or more of water, oxygen, and carbon dioxide. Chemical activation is carried out by impregnating the baked briquettes or graded granules in the presence of a strong acid, strong alkali, or salt. It should be noted that whether each of the above steps is included in the processing sometimes depends on the carbon-containing material provided. For example, when the carbon-containing material is coconut, the process steps do not include "repolymerization," which is the process of mixing the binder with crushed charcoal, pressing the crushed charcoal and binder into blocks, crushing the blocks, and grading the crushed blocks.

[0063] The result of processing carbonaceous materials is the formation of activated carbon. As described herein, this activated carbon will be referred to as "precursor activated carbon" because subsequent disclosures describe additional steps that will be applied to the precursor activated carbon to further improve its properties. The properties of the precursor activated carbon depend on several factors, including the type and amount of one or more carbonaceous materials contained therein, the type of activation, including chemical or thermal activation, and the level of activation imparted to the carbonaceous material to form the precursor activated carbon. The properties of the precursor activated carbon are also affected by other processing steps, such as the crushing and sieving of the re-agglomerated carbonaceous material particles, the level of residual binder, and the final size of the precursor activated carbon.

[0064] In all embodiments, apart from the steps described above, the precursor activated carbon is not separately treated or oxidized. Therefore, the adsorption capacity for various disinfection byproducts or other contaminants is primarily due to the retention of the precursor activated carbon's own adsorption capacity and is not particularly dependent on catalytic effects. In some embodiments, due to the internal porous structure of the precursor activated carbon, it retains its adsorption capacity for virtually all organic compounds, including chloroform, VOCs, PFAS, and newly emerging contaminants.

[0065] Oxidation of precursor activated carbon

[0066] This disclosure considers the optional oxidation of precursor activated carbon. In some embodiments, the precursor activated carbon is oxidized after activation. In other embodiments, the precursor activated carbon is not oxidized after activation. Oxidation of precursor activated carbon refers to the exposure of the precursor activated carbon to oxygen molecules at a temperature sufficient to impart oxygen substances or complexes to the surface of the activated carbon. Oxidation does not take into account a substantial change in the pore structure of the precursor activated carbon.

[0067] For example, in some embodiments, oxidation is performed by exposing the feedstock to an oxygen-containing environment and heating the feedstock to a temperature of about 150°C to about 1050°C. The oxidation temperature may be about 150°C to about 250°C, about 250°C to about 350°C, about 350°C to about 450°C, about 450°C to about 550°C, about 550°C to about 650°C, about 650°C to about 750°C, or about 750°C to about 850°C, or any of those endpoints disclosed, or any range consisting of any of the foregoing ranges or combinations of values ​​within these ranges. In different embodiments, the oxygen-containing environment is one or more of the following: atmosphere, oxygen (O2), oxygen plasma, hydrogen peroxide (H2O2), ozone (O3), nitrous oxide (N2O), or carbon dioxide (CO2).

[0068] In some implementations, the oxygen-containing environment is dry and contains no moisture or substantially no measurable moisture. The choice of oxidation temperature, as well as the oxidant and oxidation process, does not substantially alter the pore structure of the precursor activated carbon. Therefore, if a more oxidizing oxygen-containing environment is chosen, the temperature must be lowered to reduce the likelihood of additional activation. Alternatively, if a higher temperature is chosen, a less oxidizing oxygen-containing environment must be selected to reduce the likelihood of additional activation.

[0069] Oxidation can also be accomplished by electrochemical methods. It should be noted that carbon oxidizes slowly at room temperature in the presence or absence of moisture in air, and although slow, this oxidation will eventually be sufficient to produce oxidized carbon precursors. Alternatively, carbon can be oxidized in a non-thermal process in the liquid or gas phase at temperatures below about 100°C using hydrogen peroxide, ozone, chlorine, persulfates, percarbonates, oxidizing acids such as nitric acid, air, pure oxygen, or any combination thereof. In some embodiments, the oxidation step is omitted; that is, the adsorbent feedstock is not oxidized by any step that is faster than the slow oxidation that occurs naturally at room temperature under normal conditions described above.

[0070] Cu-Fe-N doping

[0071] After preparing and optionally oxidizing the precursor activated carbon, the precursor activated carbon is further treated by doping with a copper-iron-nitrogen (Cu-Fe-N) compound. Cu-Fe-N doping imparts a Cu-Fe-N complex to the surface of the precursor activated carbon, thereby catalytically sterilizing byproducts. Doping is achieved by contacting the precursor activated carbon with at least one copper source, at least one iron source, and at least one nitrogen source. In some embodiments, a single compound is a source of all three: copper, iron, and nitrogen. In still other embodiments, a first compound is a source of copper and iron, and a second compound is a source of nitrogen. In still other embodiments, a single compound is a source of copper and nitrogen, and a second compound is a source of iron. In still other embodiments, a single compound is a source of iron and nitrogen, and a second compound is a source of copper.

[0072] The copper source is unrestricted and includes one or more of the following: copper(II) sulfate pentahydrate (CuSO4·5H2O), copper(II) chloride (CuCl2), copper(II) chloride dihydrate (CuCl2·2H2O), copper(II) nitrate (Cu(NO3)2), copper(II) nitrate monohydrate (Cu(NO3)2·H2O), copper(II) sesquihydrate (Cu(NO3)2·1.5H2O), copper(II) hemipentahydrate (Cu(NO3)2·2.5H2O), copper(II) nitrate trihydrate (Cu(NO3)2·3H2O), copper(II) nitrate hexahydrate ([Cu(H2O)6](NO3)2), copper(II) acetate (Cu(CH3COO)2), copper(II) acetate monohydrate (Cu(CH3COO)2H2O), copper(II) formate, Cu(NH3)6 +2Basic copper carbonate Cu2(OH)2CO3, compounds thereof, mixtures thereof, or combinations thereof; in some embodiments, the copper source is provided as part of the aqueous solution. The iron source is not limited and includes one or more of the following: ferric(III) hexahydrate (FeCl3·6H2O), ferric(II) tetrahydrate (FeCl2·4H2O), ferric(III) ammonium sulfate dodecahydrate (NH4Fe(SO4)·12H2O), ferrous(II) sulfate heptahydrate (Fe2SO4·7H2O), ferric(III) ammonium oxalate trihydrate ((NH4)3Fe(C2O4)3·3H2O), ammonium hexacyanoferrate (II) hydrate ((NH4)4[Fe(CN)6]·xH2O), ferric(III) ammonium citrate ((NH4)5[F The following are listed as examples of ferric ferrocyanide (Na4Fe(CN)6·10H2O), sodium ferrooxate (Na3Fe(C2O4)3), potassium ferrocyanide trihydrate (K4[Fe(CN)6]·3H2O), potassium ferricyanide (K3[Fe(CN)6]), potassium ferrooxate (K2[Fe(C2O4)2]), ferrous(II) acetate tetrahydrate ((CH3COO)2Fe·4H2O), ferrous lactate dihydrate, ferrous lactate trihydrate, urea (CO(NH2)2), dicyandiamide (DCD), compounds thereof, mixtures thereof, or combinations thereof. In some embodiments, the iron source is provided as part of the aqueous solution. The nitrogen source is not limited and in some embodiments includes any nitrogen source having an oxidation state of -3. Examples of nitrogen sources having an oxidation state of -3 include one or more of the following: urea (which has the formula CO(NH2)2) or dicyandiamide (DCD) or compounds thereof, mixtures thereof, or combinations thereof. In some embodiments, the nitrogen source is provided as part of an aqueous solution. It should be noted that anhydrous copper or iron salt precursors, including CuCl2, FeCl3, and FeCl2, similar to their hydrated counterparts, including CuCl2·2H2O, FeCl3·6H2O, and FeCl2·4H2O, are used in the doping process.

[0073] While the above description of a nitrogen source, or a single source of iron or copper combined with nitrogen, or a single source of iron, copper, and nitrogen, includes several listed compounds, such compounds or combinations of compounds are not limited thereto. In particular, the applicant has found that nitrogen compounds with an oxidation state of -3 possess excellent properties. Therefore, in some embodiments, the nitrogen source is not limited as long as it has an oxidation state of -3. The oxidation state of copper or iron is not considered important to the results.

[0074] The doping process is not limited. In some embodiments, doping is carried out in a single stage. In a single-stage process, the precursor activated carbon is treated by contacting it with a single solution comprising copper, iron, and nitrogen compounds. For example, in one embodiment, doping is carried out in a single stage by contacting the precursor activated carbon with an aqueous solution containing copper(II) pentahydrate, ferric(III) hexahydrate, and urea. In another embodiment, doping is carried out in a single stage by contacting the precursor activated carbon with an aqueous solution containing copper(II) pentahydrate, ferric(III) hexahydrate, and dicyandiamide.

[0075] In the single-stage process of doped precursor activated carbon, the amount of copper compound, iron compound and nitrogen compound doped can be controlled by changing one or more of the following: the concentration of copper compound in solution, the concentration of iron compound in solution, the concentration of nitrogen in solution, the contact time between solution and precursor activated carbon, or the temperature of solution.

[0076] In a single-stage process, after solution doping, the precursor activated carbon is dried to remove water or other solvents, thereby retaining copper, iron, and nitrogen compounds on the precursor activated carbon. The drying process is unrestricted and is carried out by drying in air at approximately 100°C to approximately 150°C for up to 2 hours.

[0077] Following the single-stage process, the resulting doped and dried precursor activated carbon comprises varying amounts of copper, iron, and nitrogen. For example, when measured based on the dried precursor activated carbon, the amount of copper added is approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, approximately 2.2 wt%, and approximately 2.3 wt%. %, about 2.4 wt%, about 2.5 wt%, about 2.6 wt%, about 2.7 wt%, about 2.8 wt%, about 2.9 wt%, about 3.0 wt%, about 3.1 wt%, about 3.2 wt%, about 3.3 wt%, about 3.4 wt%, about 3.5 wt%, about 3.6 wt%, about 3.7 wt%, about 3.8 wt%, about 3.9 wt%, about 4.0 wt%, about 4.1 wt%, about 4.2 wt%, about 4.3 wt%, about 4.4 wt%, about 4.5 wt%, or any range including one or more of the above values ​​as endpoints. When measured based on dry precursor activated carbon, the amount of added iron was approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, approximately 2.2 wt%, and approximately 2.3 wt%. About 2.4 wt%, about 2.5 wt%, about 2.6 wt%, about 2.7 wt%, about 2.8 wt%, about 2.9 wt%, about 3.0 wt%, about 3.1 wt%, about 3.2 wt%, about 3.3 wt%, about 3.4 wt%, about 3.5 wt%, about 3.6 wt%, about 3.7 wt%, about 3.8 wt%, about 3.9 wt%, about 4.0 wt%, about 4.1 wt%, about 4.2 wt%, about 4.3 wt%, about 4.4 wt%, about 4.5 wt%, or any range including one or more of the above values ​​as endpoints.When measured based on dry precursor activated carbon, the nitrogen content was approximately 1.5 wt%, approximately 2.0 wt%, approximately 2.2 wt%, approximately 2.5 wt%, approximately 3.0 wt%, approximately 3.5 wt%, approximately 4.0 wt%, approximately 4.5 wt%, approximately 5.0 wt%, approximately 5.5 wt%, approximately 6.0 wt%, approximately 6.5 wt%, approximately 7.0 wt%, approximately 7.5 wt%, approximately 8.0 wt%, approximately 8.3 wt%, approximately 8.5 wt%, approximately 9.0 wt%, approximately 9.5 wt%, approximately 10.0 wt%, approximately 10.5 wt%, and approximately 11.0 wt%. Approximately 11.5 wt%, approximately 12.0 wt%, approximately 12.5 wt%, approximately 13.0 wt%, approximately 13.5 wt%, approximately 14.0 wt%, approximately 14.5 wt%, approximately 15.0 wt%, approximately 15.5 wt%, approximately 16.0 wt%, approximately 16.5 wt%, approximately 16.7 wt%, approximately 17.0 wt%, approximately 17.5 wt%, approximately 18.0 wt%, approximately 18.5 wt%, approximately 19.0 wt%, approximately 19.5 wt%, approximately 20.0 wt%, or any range including one or more of the above values ​​as endpoints.

[0078] Figure 2 An embodiment of the doping process 50 in a single-stage configuration is shown. In the doping process 50, precursor activated carbon is contacted with an aqueous solution containing a copper source, an iron source, and a nitrogen source, as shown in box 51. Next, the contacted precursor activated carbon is dried 52. After drying, the doped precursor activated carbon is ready for calcination.

[0079] In another embodiment of the single-stage process, precursor activated carbon is provided and subsequently sprayed with an aqueous solution containing dissolved copper(II) sulfate pentahydrate, urea, and dissolved ferric(III) chloride hexahydrate dopants. The precursor activated carbon is then allowed to stand for a predetermined period of time. After standing, the precursor activated carbon is dried at a predetermined temperature for a predetermined period of time. As an example, the aqueous solution contains approximately 0.19 wt% Cu, approximately 12.1 wt% N, and approximately 0.19 wt% Fe, each measured relative to the weight of the dried precursor activated carbon. Furthermore, the standing time can be approximately 40 minutes, approximately 50 minutes, approximately 60 minutes, approximately 70 minutes, or approximately 80 minutes. Drying is carried out at a temperature of approximately 100°C for approximately 4 hours, but drying is not limited and these times and temperatures can vary. Once the drying step is complete, the doped precursor activated carbon is ready for calcination.

[0080] In one alternative implementation, doping is performed in two stages. In one two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and iron, optionally drying the copper and iron-containing precursor activated carbon, and then contacting it with a nitrogen-containing solution and drying the copper, iron, and nitrogen-containing precursor activated carbon. In another two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and nitrogen, optionally drying the copper and nitrogen-containing precursor activated carbon, and then contacting it with an iron-containing solution and drying the copper, iron, and nitrogen-containing precursor activated carbon. In yet another two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and nitrogen, optionally drying the copper and nitrogen-containing precursor activated carbon, and then contacting it with an iron-containing solution and drying the copper, iron, and nitrogen-containing precursor activated carbon. In another two-stage process, the precursor activated carbon is treated by first contacting the precursor activated carbon with a solution containing iron and nitrogen, optionally drying the precursor activated carbon containing iron and nitrogen, and then contacting the precursor activated carbon containing iron and nitrogen with a solution containing copper, and drying the precursor activated carbon containing copper, iron and nitrogen.

[0081] In one such embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate and an aqueous solution containing dissolved ferric(III) hexahydrate, and then contacting the precursor activated carbon with an aqueous solution of urea. In another such embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate and an aqueous solution of urea, and then contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) hexahydrate. In yet another such embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) hexahydrate and an aqueous solution of urea, and then contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate.

[0082] In another embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate and an aqueous solution containing dissolved ferric(III) hexahydrate, and then contacting the precursor activated carbon with an aqueous solution of dicyandiamide. In another embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate and an aqueous solution of dicyandiamide, and then contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) hexahydrate. In another embodiment, doping is performed in two stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) hexahydrate and an aqueous solution of dicyandiamide, and then contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) pentahydrate.

[0083] In the two-stage process of doping precursor activated carbon, the amount of doped copper compound, iron compound, and nitrogen compound can be controlled by changing one or more of the following: the concentration of copper compound in the solution, the concentration of iron compound in the solution, the concentration of nitrogen in the solution, the contact time of one or more of the copper-containing solution, iron-containing solution, or nitrogen-containing solution with precursor activated carbon, or the temperature of one or more of the copper-containing solution, iron-containing solution, or nitrogen-containing solution.

[0084] Following the two-stage process, the resulting doped and dried precursor activated carbon comprises specific amounts of copper, iron, and nitrogen. For example, when measured based on the dried precursor activated carbon, the amount of copper is approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, and approximately 2.2 wt%. Approximately 2.3 wt%, approximately 2.4 wt%, approximately 2.5 wt%, approximately 2.6 wt%, approximately 2.7 wt%, approximately 2.8 wt%, approximately 2.9 wt%, approximately 3.0 wt%, approximately 3.1 wt%, approximately 3.2 wt%, approximately 3.3 wt%, approximately 3.4 wt%, approximately 3.5 wt%, approximately 3.6 wt%, approximately 3.7 wt%, approximately 3.8 wt%, approximately 3.9 wt%, approximately 4.0 wt%, approximately 4.1 wt%, approximately 4.2 wt%, approximately 4.3 wt%, approximately 4.3 wt%, approximately 4.4 wt%, approximately 4.5 wt%. When measured based on dry precursor activated carbon, the amount of iron is approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, approximately 2.2 wt%, approximately 2.3 wt%, approximately... 2.4 wt%, about 2.5 wt%, about 2.6 wt%, about 2.7 wt%, about 2.8 wt%, about 2.9 wt%, about 3.0 wt%, about 3.1 wt%, about 3.2 wt%, about 3.3 wt%, about 3.4 wt%, about 3.5 wt%, about 3.6 wt%, about 3.7 wt%, about 3.8 wt%, about 3.9 wt%, about 4.0 wt%, about 4.1 wt%, about 4.2 wt%, about 4.3 wt%, about 4.4 wt%, about 4.5 wt%, or any range including one or more of the above values ​​as endpoints.When measured based on dry precursor activated carbon, the nitrogen content was approximately 1.5 wt%, approximately 2.0 wt%, approximately 2.2 wt%, approximately 2.5 wt%, approximately 3.0 wt%, approximately 3.5 wt%, approximately 4.0 wt%, approximately 4.5 wt%, approximately 5.0 wt%, approximately 5.5 wt%, approximately 6.0 wt%, approximately 6.5 wt%, approximately 7.0 wt%, approximately 7.5 wt%, approximately 8.0 wt%, approximately 8.3 wt%, approximately 8.5 wt%, approximately 9.0 wt%, approximately 9.5 wt%, approximately 10.0 wt%, approximately 10.5 wt%, and approximately 11.0 wt%. Approximately 11.5 wt%, approximately 12.0 wt%, approximately 12.5 wt%, approximately 13.0 wt%, approximately 13.5 wt%, approximately 14.0 wt%, approximately 14.5 wt%, approximately 15.0 wt%, approximately 15.5 wt%, approximately 16.0 wt%, approximately 16.5 wt%, approximately 16.7 wt%, approximately 17.0 wt%, approximately 17.5 wt%, approximately 18.0 wt%, approximately 18.5 wt%, approximately 19.0 wt%, approximately 19.5 wt%, approximately 20.0 wt%, or any range including one or more of the above values ​​as endpoints.

[0085] Figure 3 An embodiment of the doping process 50 in a two-stage configuration is shown. In the doping process 50, precursor activated carbon is contacted with an aqueous solution containing a copper source and an iron source, as shown in box 51. Next, the precursor activated carbon is dried 52. After drying 52, the precursor activated carbon is contacted with an aqueous solution containing a nitrogen source, as shown in box 53. After contact with the aqueous solution containing the nitrogen source, the precursor activated carbon is dried 54. Following this second drying step, the doped precursor activated carbon is ready for calcination.

[0086] In one alternative implementation, doping is carried out in three stages. In one three-stage process, the precursor activated carbon is treated by first contacting it with a copper-containing solution and optionally drying the copper-containing precursor activated carbon; secondly, contacting it with an iron-containing solution and optionally drying the copper- and iron-containing precursor activated carbon; and thirdly, contacting it with a nitrogen-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon. In another three-stage process, the precursor activated carbon is treated by first contacting it with an iron-containing solution and optionally drying the iron-containing precursor activated carbon; secondly, contacting it with a copper-containing solution and optionally drying the iron- and copper-containing precursor activated carbon; and thirdly, contacting it with a nitrogen-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon. In another three-stage process, the precursor activated carbon is treated by first contacting it with a copper-containing solution and optionally drying the copper-containing precursor activated carbon; secondly, contacting it with a nitrogen-containing solution and optionally drying the copper- and nitrogen-containing precursor activated carbon; and thirdly, contacting it with an iron-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon. In yet another three-stage process, the precursor activated carbon is treated by first contacting it with an iron-containing solution and optionally drying the iron-containing precursor activated carbon; secondly, contacting it with a nitrogen-containing solution and optionally drying the iron- and nitrogen-containing precursor activated carbon; and thirdly, contacting it with a copper-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon. In another three-stage process, the precursor activated carbon is treated by first contacting it with a nitrogen-containing solution and optionally drying the nitrogen-containing precursor activated carbon; secondly, contacting the nitrogen-containing precursor activated carbon with a copper-containing solution and optionally drying the nitrogen- and copper-containing precursor activated carbon; and thirdly, contacting the nitrogen- and copper-containing precursor activated carbon with an iron-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon. In yet another three-stage process, the precursor activated carbon is treated by first contacting it with a nitrogen-containing solution and optionally drying the nitrogen-containing precursor activated carbon; secondly, contacting the nitrogen-containing precursor activated carbon with an iron-containing solution and optionally drying the nitrogen- and iron-containing precursor activated carbon; and thirdly, contacting the nitrogen- and iron-containing precursor activated carbon with a copper-containing solution and drying the copper-, iron-, and nitrogen-containing precursor activated carbon.

[0087] In one such embodiment, doping is performed in three stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper(II) pentahydrate; second, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric(III) hexahydrate; and third, the precursor activated carbon is contacted with an aqueous solution of urea. In another embodiment, doping is performed in three stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric(III) hexahydrate; second, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper(II) pentahydrate; and third, the precursor activated carbon is contacted with an aqueous solution of urea. In yet another embodiment, doping is performed in three stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper(II) pentahydrate; second, the precursor activated carbon is contacted with an aqueous solution of urea; and third, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric(III) hexahydrate. In another embodiment, doping is performed in three stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric(III) hexahydrate; second, the precursor activated carbon is contacted with an aqueous solution of urea; and third, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper(II) pentahydrate. (This text is repeated three times in the original.)

[0088] In another embodiment, doping is performed in three stages by first contacting the precursor activated carbon with an aqueous solution of dissolved copper(II) sulfate pentahydrate, then contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) chloride hexahydrate, and finally contacting the precursor activated carbon with an aqueous solution of dicyandiamide. In another embodiment, doping is performed in three stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) chloride pentahydrate, then contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) sulfate pentahydrate, and finally contacting the precursor activated carbon with an aqueous solution of dicyandiamide. In another embodiment, doping is performed in three stages by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper(II) sulfate pentahydrate, then contacting the precursor activated carbon with an aqueous solution of dicyandiamide, and finally contacting the precursor activated carbon with an aqueous solution containing dissolved ferric(III) chloride hexahydrate. In another embodiment, doping is performed in three stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric(III) hexahydrate; second, the precursor activated carbon is contacted with an aqueous solution of dicyandiamide; and third, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper(II) pentahydrate. (This text is repeated three times in the original.)

[0089] In the three-stage process of doping precursor activated carbon, the amount of doped copper compound, iron compound, and nitrogen compound can be controlled by changing one or more of the following: the concentration of copper compound in the solution, the concentration of iron compound in the solution, the concentration of nitrogen in the solution, the contact time of one or more of the copper-containing solution, iron-containing solution, or nitrogen-containing solution with precursor activated carbon, or the temperature of one or more of the copper-containing solution, iron-containing solution, or nitrogen-containing solution.

[0090] Following the three-stage process, the resulting doped and dried precursor activated carbon comprises specific amounts of copper, iron, and nitrogen. For example, when measured based on the dried precursor activated carbon, the amount of copper added is approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, approximately 2.2 wt%, and approximately 2.3 wt%. %, about 2.4 wt%, about 2.5 wt%, about 2.6 wt%, about 2.7 wt%, about 2.8 wt%, about 2.9 wt%, about 3.0 wt%, about 3.1 wt%, about 3.2 wt%, about 3.3 wt%, about 3.4 wt%, about 3.5 wt%, about 3.6 wt%, about 3.7 wt%, about 3.8 wt%, about 3.9 wt%, about 4.0 wt%, about 4.1 wt%, about 4.2 wt%, about 4.3 wt%, about 4.4 wt%, about 4.5 wt%, or any range including one or more of the above values ​​as endpoints. When measured based on dry precursor activated carbon, the amount of added iron was approximately 0.1 wt%, approximately 0.2 wt%, 0.3 wt%, approximately 0.4 wt%, approximately 0.5 wt%, approximately 0.6 wt%, approximately 0.7 wt%, approximately 0.8 wt%, approximately 0.9 wt%, approximately 1.0 wt%, approximately 1.1 wt%, approximately 1.2 wt%, approximately 1.3 wt%, approximately 1.4 wt%, approximately 1.5 wt%, approximately 1.6 wt%, approximately 1.7 wt%, approximately 1.8 wt%, approximately 1.9 wt%, approximately 2.0 wt%, approximately 2.1 wt%, approximately 2.2 wt%, and approximately 2.3 wt%. About 2.4 wt%, about 2.5 wt%, about 2.6 wt%, about 2.7 wt%, about 2.8 wt%, about 2.9 wt%, about 3.0 wt%, about 3.1 wt%, about 3.2 wt%, about 3.3 wt%, about 3.4 wt%, about 3.5 wt%, about 3.6 wt%, about 3.7 wt%, about 3.8 wt%, about 3.9 wt%, about 4.0 wt%, about 4.1 wt%, about 4.2 wt%, about 4.3 wt%, about 4.4 wt%, about 4.5 wt%, or any range including one or more of the above values ​​as endpoints.When measured based on dry precursor activated carbon, the nitrogen content was approximately 1.5 wt%, approximately 2.0 wt%, approximately 2.2 wt%, approximately 2.5 wt%, approximately 3.0 wt%, approximately 3.5 wt%, approximately 4.0 wt%, approximately 4.5 wt%, approximately 5.0 wt%, approximately 5.5 wt%, approximately 6.0 wt%, approximately 6.5 wt%, approximately 7.0 wt%, approximately 7.5 wt%, approximately 8.0 wt%, approximately 8.3 wt%, approximately 8.5 wt%, approximately 9.0 wt%, approximately 9.5 wt%, approximately 10.0 wt%, approximately 10.5 wt%, and approximately 11.0 wt%. Approximately 11.5 wt%, approximately 12.0 wt%, approximately 12.5 wt%, approximately 13.0 wt%, approximately 13.5 wt%, approximately 14.0 wt%, approximately 14.5 wt%, approximately 15.0 wt%, approximately 15.5 wt%, approximately 16.0 wt%, approximately 16.5 wt%, approximately 16.7 wt%, approximately 17.0 wt%, approximately 17.5 wt%, approximately 18.0 wt%, approximately 18.5 wt%, approximately 19.0 wt%, approximately 19.5 wt%, approximately 20.0 wt%, or any range including one or more of the above values ​​as endpoints.

[0091] While single-stage, two-stage, and three-stage Cu-Fe-N doping processes have been disclosed above, these processes are not limited to them. For example, additional dopants may be applied in additional stages or as part of any solution of the contact precursor activated carbon.

[0092] The ratio of iron to copper is not limited. In some embodiments, the ratio of iron to copper is about 10:90 to about 90:10, about 30:70 to about 70:30, about 60:40 to about 40:60, about 50:50, or any range, including those falling within the ranges listed above.

[0093] Heat treatment / calcination

[0094] After one or more single-stage, two-stage, and three-stage Cu-Fe-N doping processes are completed, the doped precursor activated carbon is prepared for heat treatment, also known as calcination. During calcination, the doped precursor activated carbon is heated in the presence of an inert atmosphere to achieve additional changes in the doped precursor activated carbon.

[0095] The calcination temperature of the doped precursor activated carbon is not limited. In some embodiments, calcination is carried out at temperatures of about 400°C, about 450°C, about 500°C, about 550°C, about 600°C, about 650°C, about 700°C, about 750°C, about 800°C, about 850°C, about 900°C, about 950°C, about 1000°C, about 1050°C, or any range including one or more of the above values ​​as endpoints. In one embodiment, the calcination temperature is from about 900°C to about 1000°C.

[0096] The inert atmosphere used for calcination is an atmosphere that, at a specific temperature, does not cause any substantial oxidation or activation of the doped precursor activated carbon, thereby not altering the pore structure of the doped precursor activated carbon. Therefore, in many embodiments, this atmosphere does not contain oxygen, carbon dioxide, or water, or contains only small amounts of oxygen, carbon dioxide, or water that do not cause any oxidation or activation. Examples of atmospheres used for calcination include one or more of nitrogen (N2), helium, neon, argon, krypton, xenon, and combinations thereof. When calcination is complete, the resulting product is called an adsorbent material.

[0097] In some embodiments, the adsorbent material is granular activated carbon (GAC), defined as activated carbon particles whose size is retained on a 50-mesh sieve (approximately 0.300 mm pores). In other embodiments, the adsorbent material is powdered activated carbon (PAC), defined as particles that pass through an 80-mesh sieve (approximately 0.180 mm pores). While these particle size ranges are mentioned for activated carbon adsorbent materials, it is also contemplated that any disclosed adsorbent material can be measured through the aforementioned 50-mesh and 80-mesh sieve sizes. In other embodiments, the adsorbent material is granular activated carbon.

[0098] Performance Measurement / Adsorbent Characterization

[0099] The properties of the adsorbent materials disclosed herein are measured in various ways, including the “chloramine destruction value” (CDN) as defined below. The chloramine destruction value quantifies the amount of chloramine that can be removed from a fluid by the adsorbent materials of this disclosure. The measurement of CDN is known in the art, for example in U.S. Patent No. 10,702,853, entitled “CHLORAMINE AND CHLORINE REMOVAL MATERIAL AND METHODS FOR MAKING THE SAME,” granted July 7, 2020, which is incorporated herein by reference in its entirety.

[0100] CDN is the absolute value of a first-order linear kinetic fit multiplied by 1000, applied to the natural logarithm of the concentration of chloramine in water over time, where the initial concentration of chloramine decreases over a 150-minute time period. The form of chloramine is pH-dependent when ammonia is in equilibrium with chlorine in solution. The chloramine solution contains ammonium chloride; sodium hypochlorite and deionized water are mixed to obtain a 1 L solution of 300 ppm chloramine at pH 9.0. At pH 9.0, chloramine in equilibrium is the most difficult form of monochloramine to break down. A sodium carbonate buffer solution is used to maintain the solution pH during evaluation. The chlorine solution contains sodium hypochlorite and deionized water to obtain a 1 L solution of 300 ppm chlorine. One L of the corresponding 300 ppm solution is added to an Erlenmeyer flask, which is placed in a water bath controlled at 20°C. A constant volume of 2.0 mL of activated carbon (80 × 325 mesh) is added to the stirred 1 L of chloramine or chlorine solution for each sample analysis. The volume of carbon used was determined by the apparent density of 80 × 325 carbon as measured by ASTM Method D-2854. The concentration of total chlorine in the solution was measured by taking aliquots of the sample at different time points within a 150-minute period and then analyzing the total chlorine using the standard HACH colorimetric method EPA-accepted 10070.

[0101] After experimental analysis of the adsorbent materials, the concentration versus time data for each adsorbent material sample were replotted as the natural logarithm of total chlorine concentration against time to linearize the data according to first-order kinetics. A linear fit was then applied to the data, and the slope of the linear fit was determined. The slope is always negative because the initial concentration of total chlorine decreases over a 150-minute period. Therefore, the absolute value of the slope multiplied by 1000 is used to quantify the rate of chloramine and chlorine destruction (removal). The larger the absolute slope, the better the adsorbent material removes chlorine and chloramine. For these measurements, the slope obtained from the linear fit of the first-order kinetic experimental data (again multiplied by 1000) is called the "chloramine destruction value" or CDN. In the case of chlorine destruction, this rate is called the "chlorine destruction value" of Cl-DN. These values ​​quantify the amount of chloramine and / or chlorine that can be removed from water by the adsorbent materials or adsorbents disclosed herein.

[0102] In addition to chloramine, this disclosure also effectively removes chlorine from fluids such as water. The ability of calcined activated carbon to remove chlorine was evaluated as described above; however, the test solution was prepared without the addition of ammonium chloride, and therefore contained 300 ppm chlorine. The adsorbent material used for chlorine analysis had a particle size of approximately 325 mesh (95%). However, the analysis of chlorine concentration versus time data and the corresponding first-order kinetic slope remained consistent, and the slope of the linear fit to this data was termed the “chlorine destruction value” or Cl-DN, which requantifies the amount of chlorine that can be removed from water by the adsorbent material or adsorbent of this disclosure.

[0103] For CDN, this disclosure considers approximately 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, 16.0, 16.5, 17.0, 17.5, 18.0, 18.5, 19.0, 19.5, 20.0, 20.5, 21.0, 21.5, 22.0, 22.5, 23.0, 23.5, and 24. Values ​​of .0, approximately 24.5, approximately 25.0, approximately 25.5, approximately 26.0, approximately 26.5, approximately 27.5, approximately 28.0, approximately 28.5, approximately 29.0, approximately 29.5, approximately 30.0, approximately 35.0, approximately 40.0, approximately 45.0, approximately 50.0, approximately 55.0, approximately 60.0, approximately 65.0, approximately 70.0, approximately 75.0, approximately 80.0, approximately 85.0, approximately 90.0, approximately 95.0, approximately 100.0, approximately 105.0, approximately 110.0, approximately 115.0, approximately 120.0, approximately 125.0, approximately 130.0, approximately 135.0, approximately 140.0, approximately 145.0, approximately 150.0, or any range including at least two of these values ​​as endpoints. Alternatively, the CDN can be a range with these values ​​as performance lower limits, such as at least about 4.0, at least about 4.5, at least about 5.0, at least about 10.0, at least about 15.0, at least about 20.0, at least about 23.0, at least about 50.0, at least about 75.0, or at least about 100.0. In some embodiments, the chloramine destruction value is measured relative to monochloramine.

[0104] The "peroxide depletion value," also known as "peroxide value," was also measured. Peroxide value is a volumetric test, meaning that performance is measured and normalized to a specified volume of adsorbent material. The testing of peroxide value is well known in the art and is described, for example, in U.S. Patent No. 5,470,748, the entire contents of which are incorporated herein by reference.

[0105] During peroxide value testing, the adsorbent material is first pulverized to a fine sieve size fraction, where at least 90% by weight, and in some tests at least 95% by weight, of the adsorbent will pass through a 325-mesh US Standard series sieve (44 μm opening size). A specified amount of pulverized adsorbent material is placed in a vacuum flask (Dewar flask), and 100 mL of deionized water is added to the flask. The addition of deionized water is made so that any pulverized adsorbent material adhering to the sides of the flask is carried into the water mass at the bottom of the flask. Next, 50 mL of an equal volume of buffer solution is added to the flask. The buffer solution is 0.5 mol in K₂HPO₄ and 0.5 mol in KH₂PO₄. After adding the buffer solution, a magnetic stir bar is added to the flask and energized to begin stirring. The stirring speed is increased until a vortex with a depth greater than approximately 0.5 inches (1.27 cm) is formed in the mixture, reaching the optimal stir bar speed. The optimal stir bar speed is selected such that any further increase in stir bar speed does not significantly affect the peroxide decomposition time.

[0106] As mentioned earlier, during the peroxide value test, a specified amount of adsorbent material was added to a buffered hydrogen peroxide solution. Because the test is volumetric, the specified amount of adsorbent material added to the buffered hydrogen peroxide solution was based on half (1 / 2) of the apparent density of the adsorbent material. Specifically, when the apparent density of the adsorbent material is expressed in g / cm³... 3 When reported in units, the mass (in grams) of adsorbent material added to the solution is equal to half (1 / 2) of the measured apparent density of the adsorbent material. In the buffer solution, the catalytic properties of the adsorbent material lead to the catalytic destruction of peroxides (i.e., hydrogen peroxide decomposes into water and oxygen).

[0107] The catalysis of hydrogen peroxide is exothermic. Therefore, the decomposition rate of the adsorbent material can be approximately estimated by measuring the temperature of the buffer solution over time. As used herein, "peroxide value" is the length of time, in minutes, required for a buffer solution containing a sample of adsorbent material to reach 75% of the highest recorded temperature. A faster time and therefore a lower peroxide value indicate higher catalytic activity and thus higher performance adsorbent material. In some implementations, the peroxide damage value, measured in minutes, is approximately 1.0, approximately, approximately 1.5, approximately 2.0, approximately 2.1, approximately 2.2, approximately 2.3, approximately 2.4, approximately 2.5, approximately 2.6, approximately 2.7, approximately 2.8, approximately 2.9, approximately 3.0, approximately 3.1, approximately 3.2, approximately 3.3, approximately 3.4, approximately 3.5, approximately 3.6, approximately 3.7, approximately 3.8, approximately 3.9, approximately 4.0, approximately 4.1, approximately 4.2, approximately 4.3, approximately 4.4, approximately 4.5, approximately 4.6, approximately 4.7, approximately 4.8, approximately 4.9, approximately 5.0, approximately 5.1, approximately 5.2, approximately 5.3, approximately 5.4, approximately... 5.5, approximately 5.6, approximately 5.7, approximately 5.8, approximately 5.9, approximately 6.0, approximately 6.1, approximately 6.2, approximately 6.3, approximately 6.4, approximately 6.5, approximately 6.6, approximately 6.7, approximately 6.8, approximately 6.9, approximately 7.0, approximately 7.1, approximately 7.2, approximately 7.3, approximately 7.4, approximately 7.5, approximately 7.6, approximately 7.7, approximately 7.8, approximately 7.9, approximately 8.0, approximately 8.1, approximately 8.2, approximately 8.3, approximately 8.4, approximately 8.5, approximately 8.6, approximately 8.7, approximately 8.8, approximately 8.9, approximately 9.0, approximately 9.1, approximately 9.2, approximately 9.3, approximately 9.4, approximately 9.5, approximately 9.6, approximately 9.7, Approximately 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3 Approximately 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, 14.8, 14.9, 15.0, 15.1, 15.2, 15.3, 15.4, 15.5, 15.6, 15.7, 15.8, 15.9, 16.0, 16.1, 16.2, 16.3, 16.4, 16.5, 16.6, 16.7, 16.8, 16.9. about 17.0, about 17.1, about 17.2, about 17.3, about 17.4, about 17.5, about 17.6, about 17.7, about 17.8, about 17.9, about 18.0, about 18.1, about 18.2, about 18.3, about 18.4, about 18.5, about 18.6, about 18.7, about 18.8, about 18.9, about 19.0, about 19.1, about 19.2, about 19.3, about 19.4, about 19.5, about 19.6, about 19.7, about 19.8, about 19.9, about 20.0, or any range formed by two or more of the above values ​​as endpoints of the range. In some implementations, the peroxide damage value, measured in minutes, is about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, or any range formed by two or more of the above values ​​as endpoints of that range.

[0108] Peroxide value is correlated with and to some extent with CDN and Cl-DN, as they are each measures of the catalytic activity of an adsorbent material. However, this correlation is not always precise, as each represents a different aspect of the catalytic activity of the adsorbent material. Furthermore, catalytic activity is only useful for those compounds that are catalyzed, but other compounds must be adsorbed to be effectively removed from the fluid stream. Therefore, a good adsorbent material must perform well in more than one of the following tests: CDN, Cl-DN, peroxide value, and adsorption test, enabling it to effectively remove a wide range of compounds from the fluid stream.

[0109] Fluid processing

[0110] Other embodiments involve methods for purifying fluids such as water by using chlorine and chloramines to destroy the adsorbent material. In one embodiment, the fluid is treated by flowing the fluid through a bed of adsorbent material, introducing the fluid onto a filter comprising the adsorbent material, introducing the adsorbent material into a container for containing the fluid, and so on. In some embodiments, the above steps are combined in parallel or subsequently combined in series. In some embodiments, the fluid is water. In other embodiments, the fluid is water for consumption by humans, plants, animals, or marine organisms. In some embodiments, the fluid is in liquid form.

[0111] In other embodiments, the method for purifying the fluid includes additional steps. For example, in some embodiments, the method for purification includes filtering the fluid using, for example, a screen or sand filter before, after, or before and after contacting an adsorbent material to remove particles. In further embodiments, the method includes disinfecting the water to remove biological contaminants such as bacteria or other microorganisms, and in some embodiments, the method includes introducing a disinfectant into the fluid or irradiating the fluid with ultraviolet radiation. In other embodiments, the method includes steps such as clarifying the fluid, adjusting the pH of the fluid, and combinations thereof. In each of the above embodiments, the fluid may be water.

[0112] Example

[0113] The following experimental examples are intended to better illustrate the specific implementation schemes, and they are not intended to limit this disclosure.

[0114] Single-stage process example

[0115] Coconut carbonaceous material is provided, processed, and activated. The resulting coconut activated carbon, available under the product name OLC from Calgon Carbon Corporation, is referred to as precursor activated carbon. The coconut activated carbon is granular and has a test size of 12 × 40 mm. The precursor activated carbon is oxidized in some tests but not in others. After providing the precursor activated carbon and, in some cases, optionally undergoing an oxidation step, the precursor activated carbon is prepared to be doped with Cu, Fe, and N.

[0116] During Fe, Cu, and N doping, a single-stage doping process is performed. The single-stage doping process uses oxidized or unoxidized precursor activated carbon doped with copper, iron, and nitrogen. During the single-stage doping process, an aqueous solution containing CuSO4·5H2O, FeCl3·6H2O, and urea is contacted with the oxidized or unoxidized precursor activated carbon to obtain 0.2 wt% to 1.0 wt% Cu, 0.2 wt% to 1.0 wt% Fe, and 2.2 wt% to 8.3 wt% to 15 wt% N on the carbon, based on measurements of the dried precursor activated carbon. The aqueous solution is contacted with the precursor activated carbon at 25°C for up to 30 minutes. After contacting the precursor activated carbon with the aqueous solution, the precursor activated carbon is dried, thereby producing the doped precursor activated carbon.

[0117] Finally, the doped precursor activated carbon was calcined. During calcination, the doped precursor activated carbon was heated to 950°C in a pure N2 atmosphere for 1 hour.

[0118] Experimental results

[0119] Figure 4The effect of varying the amount of nitrogen doped on the precursor activated carbon on CDN and peroxide value was shown while maintaining the total metal level at approximately 0.5% by weight. Figure 4 The result shown is precursor activated carbon formed from coconut carbonaceous material and subsequently oxidized. Doping involves adding Cu, Fe, and N to this oxidized activated carbon. Figure 4 The results show that, for a total metal loading level of 0.5 wt%, the CDN and peroxide damage values ​​do not increase substantially after doping with approximately 4 wt% nitrogen.

[0120] Figure 5 and Figure 6 This study demonstrates the effect of metal doping on CDN and peroxide damage values ​​of Cu, Fe, and N-doped precursor activated carbon prepared from coconut carbonaceous materials. Compared to precursor activated carbon formed from coconut carbonaceous materials doped with Cu and N or Fe and N, this Cu, Fe, and N-doped precursor achieved a higher CDN value. Furthermore, compared to Cu and N or Fe and N doping, this Cu, Fe, and N-doped precursor also achieved a faster (and therefore superior) peroxide damage value.

[0121] Figure 7 The study compares the effects of varying the amount of nitrogen added to the oxidized precursor activated carbon on CDN and peroxide damage values ​​while maintaining the total metal levels of Cu-N, Fe-N, and Cu-Fe-N at approximately 0.5% by weight.

[0122] Figure 8 The effects of varying the amount of nitrogen added to the unoxidized precursor activated carbon formed from coconut carbonaceous material, doped with Cu, Fe, and N, on both CDN and peroxide damage values ​​were shown. Figure 8 The results show that for a total metal loading level of 0.5 wt%, CDN increases linearly with the addition of more nitrogen to carbon. Peroxide damage values ​​also decrease with the addition of more nitrogen to carbon.

[0123] Figure 9 and Figure 10 The effects of metal loading on CDN and peroxide damage values ​​are shown for Cu, Fe, and N-doped unoxidized coconut-derived precursor activated carbon. The Cu, Fe, and N-doped unoxidized precursor activated carbon achieved a higher CDN value compared to Cu and N-doped or Fe and N-doped unoxidized precursor activated carbon. The Cu, Fe, and N-doped unoxidized precursor activated carbon formed from coconut carbonaceous materials achieved a faster peroxide damage value compared to Cu and N-doped or Fe and N-doped unoxidized precursor activated carbon.

[0124] Table 1 shows a comparison among Cu-N, Fe-N, and Cu-Fe-N doped unoxidized activated carbons made from wood-based carbonaceous materials. When the peroxide value is listed as ">60", it indicates that no temperature peak was observed after 60 minutes of testing; the true peroxide value is a duration greater than 60 minutes. This is an indication of poor performance for this metric. BGE is granular wood-based activated carbon purchased from Calgon Carbon Corporation. It is a wood-based catalytic activated carbon used for removing chlorine and chloramines from drinking water, purchased from Ingevity Corporation, North Charleston, South Carolina.

[0125] Table 1

[0126]

[0127] In the above detailed description, reference has been made to the accompanying drawings, which form a part thereof. In the drawings, similar symbols generally identify similar parts unless the context otherwise requires. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter set forth herein. It will be readily understood that aspects of this disclosure, as generally described herein and illustrated in the drawings, can be configured, arranged, substituted, combined, separated, and designed in a wide variety of ways, all of which are explicitly covered herein.

[0128] This disclosure is not limited to the specific embodiments described in this application, which are intended to be illustrative of various aspects. Many modifications and changes may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. In addition to those listed herein, functionally equivalent methods and apparatus within the scope of this disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and changes are also intended to fall within the scope of the appended claims. This disclosure is limited only by the terms of the appended claims and the full scope of equivalents conferred by such claims. It should be understood that this disclosure is not limited to specific methods, reagents, compounds, compositions, or biological systems, which are of course subject to variation. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0129] Regarding the use of virtually any plural and / or singular terms in this document, those skilled in the art can convert from plural to singular and / or from singular to plural depending on the context and / or the application. For clarity, various singular / plural permutations may be explicitly described herein.

[0130] Those skilled in the art will understand that, in general, the terminology used herein, and especially the terminology used in the appended claims (e.g., the body of the appended claims), is generally intended as “open-ended” terms (e.g., the term “comprising” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “at least having,” the term “including” should be interpreted as “comprising but not limited to,” etc.). While various compositions, methods, and apparatuses are described as “comprising” various components or steps (interpreted as meaning “including but not limited to”), said compositions, methods, and apparatuses may also be “substantially composed of” various components and steps or “consisting of” various components and steps, and such terms should be interpreted as defining a substantially closed group of members. Those skilled in the art will also understand that if it is intended to introduce a particular number of claims, such intention should be expressly stated in the claims, and without such statement, such intention does not exist.

[0131] For example, to aid understanding, the appended claims may contain the introductory expressions “at least one” and “one or more” to introduce the claim recitation. However, the use of such expressions should not be construed as implying that a claim recitation introduced by the indefinite article “a (a / an)” limits any particular claim containing such an introductory claim recitation to embodiments containing only one such recitation, even when the same claim contains the introductory expressions “one or more” or “at least one” and indefinite articles such as “a (a / an)” (e.g., “a (a)” and / or “a (an)” should be interpreted as “at least one” or “one or more”); the same applies to the use of definite articles to introduce the claim recitation.

[0132] Furthermore, even if the specific number of claims in the introduced claims is explicitly stated, those skilled in the art should recognize that such a statement should be interpreted as referring to at least the number stated (e.g., a bare statement of "two statements," in the absence of other modifiers, refers to at least two statements or two or more statements). Moreover, in cases where conventions such as "at least one of A, B, and C" are used, generally, such a construction is intended to convey the meaning of the convention in the sense that those skilled in the art would understand (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, a system having only A, only B, only C, having A and B together, having A and C together, having B and C together, and / or having A, B, and C together, etc.). In cases where a convention such as "at least one of A, B, or C" is used, generally, such a construction is intended to convey the meaning of the convention in the sense that a person skilled in the art would understand (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, having only A, having only B, having only C, having A and B together, having A and C together, having B and C together, and / or having A, B, and C together, etc.). A person skilled in the art should also understand that any transitional words and / or expressions that propose two or more alternative terms, whether in the specification, claims, or drawings, should be understood to cover the possibility of including one of these terms, or including any or both of these terms. For example, the expression "A or B" should be understood to include the possibility of including "A" or "B" or "A and B".

[0133] Furthermore, when the features or aspects of this disclosure are described in terms of Markush groups, those skilled in the art will recognize that this disclosure is also described in terms of any individual member or subgroup of a Markush group.

[0134] As those skilled in the art will understand, for any and all purposes, such as for the purpose of providing a written description, all scopes disclosed herein also cover any and all possible subscopes and combinations thereof. Any listed scope can be readily identified as sufficiently descriptive and allowing the same scope to be decomposed into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope discussed herein can be readily decomposed into a lower third, middle third, and upper third, etc. As those skilled in the art will also understand, all language such as “at most,” “at least,” etc., includes the stated number and refers to a scope that can be subsequently decomposed into subscopes as discussed above. Finally, as those skilled in the art will understand, a scope includes each individual member. Thus, for example, a group having 1-3 components means a group having 1, 2, or 3 components. Similarly, a group having 1-5 components means a group having 1, 2, 3, 4, or 5 components, etc.

[0135] The various and other features and functions disclosed above, or their alternatives, can be combined into many other different systems or applications. Various alternatives, modifications, alterations, or improvements that are not currently foreseeable or anticipated can then be made by those skilled in the art, each of which is also intended to be covered by the disclosed embodiments.

Claims

1. An adsorbent material formed from a carbon-containing material, said carbon-containing material being activated to form precursor activated carbon, said adsorbent material comprising: Nitrogen content of 4% to 20% by weight, measured based on dried precursor activated carbon; and 0.1 wt% to 1 wt% iron and 0.1 wt% to 1 wt% copper, as measured based on dry precursor activated carbon; The weight ratio of the iron to the copper is 50:

50. The chloramine destruction value of the adsorbent material is said to be 5 to 75; and The peroxide value of the adsorbent material is less than 20 minutes.

2. The adsorbent material according to claim 1, wherein the chloramine destruction value is 20 to 75.

3. The adsorbent material as described in claim 1, wherein the peroxide value is 1 to 10 minutes.

4. The adsorbent material as described in claim 1, wherein the amount of nitrogen is 4% to 5% by weight.

5. The adsorbent material of claim 1, wherein the adsorbent material is formed of a carbon-containing material, the carbon-containing material being formed of one or more of coal, wood, and coconut.

6. The adsorbent material of claim 5, wherein at least a portion of the carbon-containing material is formed from coconut.

7. A method for manufacturing the adsorbent material as claimed in claim 1, the method comprising: Provide carbon-containing materials; The carbon-containing material is activated to form precursor activated carbon; Doped precursor activated carbon is formed by contacting the precursor activated carbon with one or more solutions containing an iron source, an iron source, and a nitrogen source. The doped precursor activated carbon is calcined in a calcining atmosphere to a temperature of at least 950°C to form an adsorbent material, wherein the calcining atmosphere does not cause any substantial oxidation or activation of the doped precursor activated carbon.

8. The method of claim 7, wherein the single solution contains the copper source, the iron source, and the nitrogen source.

9. The method of claim 7, wherein the first solution contains the copper source and the iron source, and the second solution contains the nitrogen source.

10. The method of claim 7, wherein the first solution contains the copper source and the nitrogen source, and the second solution contains the iron source.

11. The method of claim 7, wherein the first solution contains the iron source and the nitrogen source, and the second solution contains the copper source.

12. The method of claim 7, wherein the first solution contains the copper source, the second solution contains the iron source, and the third solution contains the nitrogen source.

13. The method of claim 7, wherein the doping of the precursor activated carbon is carried out in a single-stage process, the single-stage process comprising contacting the precursor activated carbon in an aqueous solution containing the copper source, the iron source and the nitrogen source.

14. The method of claim 7, wherein: The copper source is one or more of the following: CuSO4·5H2O, CuCl2, CuCl2·2H2O, Cu(NO3)2, Cu(NO3)2·H2O, Cu(NO3)2·1.5H2O, Cu(NO3)2·2.5H2O, Cu(NO3)2·3H2O, [Cu(H2O)6](NO3)2, Cu(CH3COO)2, Cu(CH3COO)2·H2O, Cu(HCOO)2, Cu2(OH)2CO3, or a mixture thereof; The iron source is one or more of the following: FeCl3·6H2O, FeCl2·4H2O, NH4Fe(SO4)·12H2O, FeSO4·7H2O, (NH4)3Fe(C2O4)3·3H2O, (NH4)4[Fe(CN)6]·xH2O, (NH4)5[Fe(C6H4O7)2], Na4Fe(CN)6·10H2O, Na3Fe(C2O4)3, K4[Fe(CN)6]·3H2O, K3[Fe(CN)6], K2[Fe(C2O4)2], (CH3COO)2Fe·4H2O, ferrous lactate dihydrate, ferrous lactate trihydrate, or mixtures thereof; and The nitrogen source is one or more compounds in which nitrogen has a -3 oxidation state.

15. The method of claim 7, wherein the calcination is carried out in a N2 atmosphere at a temperature of 950°C to 1050°C.

16. The method of claim 7, further comprising oxidizing the precursor activated carbon.

17. The method of claim 7, wherein the method does not involve oxidizing the precursor activated carbon.

18. The method of claim 14, wherein the copper source is CuSO4·5H2O, the iron source is FeCl3·6H2O, and the nitrogen source is one or more of urea or dicyandiamide.

19. The method of claim 15, wherein the calcination is carried out in a N2 atmosphere at a temperature of 950°C to 975°C.

20. A method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, the method comprising: An adsorbent material is provided, the adsorbent material being formed from a carbon-containing material activated to form precursor activated carbon, the adsorbent material comprising 4 wt% to 20 wt% nitrogen, 0.1 wt% to 1 wt% iron, and 0.1 wt% to 1 wt% copper, as measured based on dry precursor activated carbon, wherein the weight ratio of iron to copper is 50:50, wherein the chloramine destruction value of the adsorbent material is 5 to 75, and wherein the peroxide value of the adsorbent material is less than 20 minutes; and The adsorbent material is brought into contact with the fluid.

21. The method of claim 20, wherein the fluid is liquid water.

22. The method of claim 20, wherein the fluid or the adsorbent material has previously undergone a sterilization step.

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