Copper, iron, and nitrogen treated sorbent and method for making same

Abstract

The carbonaceous material, after activation to form precursor activated carbon, can be further enhanced by doping with copper, iron, and nitrogen and then calcining. This carbonaceous material is derived from coal, wood, or coconut shells. This invention also discloses a method for doping precursor activated carbon. The process produces an adsorbent material with excellent performance in removing chloramines and similar compounds from fluids (e.g., drinking water).

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 072,544, filed August 31, 2020, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to an adsorbent treated with copper, iron and nitrogen and its preparation method. [Previous Technology]

[0003] For fluids like water, disinfection is conventionally achieved by adding oxidizing compounds, ultraviolet irradiation, or both. While these techniques are effective for disinfecting water, the disinfected water may contain residual oxidizing compounds, products of oxidizing compounds dissolved in water, or reactive compounds resulting from the various constituent compounds present after irradiation. These compounds generally include chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide. These compounds are undesirable because they alter the taste of water, cause health problems, and corrode water supply system pipes.

[0004] Adsorbents are used to remove these compounds. Adsorbents can absorb and adsorb a wide variety of compounds. In particular, the pores of the adsorbent make the adsorption of these compounds possible. However, pure adsorbents are inefficient, adsorbing only a very small fraction of the compounds that need to be removed. To improve effectiveness, adsorbents are sometimes treated with compounds to form catalytic adsorbents. Catalytic substances are usually present on the surface of the adsorbent particles and, during operation, catalyze the chemical decomposition of compounds that are undesirable and poorly adsorbed or absorbed onto the adsorbent. By employing both adsorption and catalysis mechanisms, catalytic adsorbents can significantly improve efficiency compared to untreated pure adsorbents. Catalytic adsorbents have been proven effective in removing chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide from water or other fluids. Even so, various formation methods of these catalytic adsorbents still need to be improved to enhance overall adsorption performance. [Summary of the Invention]

[0005] Carbonaceous materials refer to materials that form precursor activated carbon after activation, and can be strengthened by doping with iron, copper, and nitrogen, as well as by calcination. The resulting adsorbent materials have excellent catalytic properties and are quite useful in the field of fluid purification.

[0006] The present invention provides an adsorbent material, which is made by activating a carbonaceous material to form a precursor activated carbon. The adsorbent material comprises: about 2 wt.% to about 20 wt.% nitrogen, the amount of which is based on the dried precursor activated carbon; about 0.1 wt.% to about 4 wt.% iron and copper, the amount of which is based on the dried precursor activated carbon; wherein the adsorbent material has a monochloramine elimination number of about 5 to about 75.

[0007] In another embodiment, the chloramine elimination number is about 20 to about 75.

[0008] In another embodiment, the adsorbent material has a peroxide elimination number of less than about 20 minutes.

[0009] In another embodiment, the adsorbent material has a peroxide elimination number of about 1 minute to about 10 minutes.

[0010] In another embodiment, the nitrogen content is between about 2.5 wt.% and about 5 wt.%.

[0011] In another embodiment, the nitrogen content is between about 1.4 wt.% and about 3.0 wt.%.

[0012] In another embodiment, the adsorbent material is made of a carbonaceous material, which is derived from one or more of coal, wood and coconut.

[0013] In another embodiment, at least a portion of the carbonaceous material is derived from coconut.

[0014] In another embodiment, the weight ratio of iron to copper is 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, the present invention provides a method for manufacturing an adsorbent material, the method comprising: providing a carbonaceous material; activating the carbonaceous material to form a precursor activated carbon; selectively oxidizing the precursor activated carbon; doping the precursor activated carbon by contacting the precursor activated carbon with one or more compounds, the compounds being a copper source, an iron source, and a nitrogen source, thereby forming a doped precursor activated carbon; and calcining the doped precursor activated carbon by heating in a calcining environment to raise the temperature to about 950°C, during which no substantial oxidation or activation occurs in the doped precursor activated carbon, thereby forming an adsorbent material.

[0017] In another embodiment, the copper source, the iron source and the nitrogen source are a single compound.

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

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

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

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

[0022] In another embodiment, the doping of the precursor activated carbon is performed in a single-stage process, the single-stage process including: contacting the precursor activated carbon with an aqueous solution containing the copper source, the iron source and the nitrogen source.

[0023] In another embodiment, the copper source is one or more of the following: copper sulfate pentahydrate (CuSO4·5H2O), copper chloride (CuCl2), copper chloride dihydrate (CuCl2·2H2O), copper nitrate (Cu(NO3)2), copper nitrate monohydrate (Cu(NO3)2·H2O), copper nitrate sesquihydrate (Cu(NO3)2·1.5H2O), and copper nitrate disesquihydrate (Cu(NO3)2·2.5H2O). Copper nitrate trihydrate (Cu(NO3)2·3H2O), copper nitrate hexahydrate ([Cu(H2O)6](NO3)2), copper acetate (Cu(CH3COO)2), copper acetate monohydrate (Cu(CH3COO)2H2O), copper formate tetrahydrate, Cu(NH3)6+2, basic copper carbonate (Cu2(OH)2CO3), their compounds or mixtures thereof; the iron source is one or more of the following: ferric chloride hexahydrate (FeCl3· Ferrous chloride tetrahydrate (FeCl2∙4H2O), ferric ammonium sulfate dodecahydrate (NH4Fe(SO4)2∙12H2O), ferric sulfate heptahydrate (Fe2SO4∙7H2O), ferric ammonium oxalate trihydrate ((NH4)3Fe(C2O4)3∙3H2O), ammonium hexacyanamide hydrate (NH4)4[Fe(CN)6]∙xH2O), ferric ammonium citrate ((NH4)5[Fe(C6H4O7)2]), sodium ferrocyanide decahydrate (Na4Fe(CN)6∙10H2O), sodium ferric oxalate (Na3Fe(C2O4)3), potassium ferrocyanide trihydrate (K4[Fe(CN)6]∙10H2O). The nitrogen source is one or more compounds, wherein the nitrogen oxidation state is -3.

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

[0025] In another embodiment, the oxidation step is required and performed.

[0026] In another embodiment, the oxidation step was not performed.

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

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

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

[0030] In another embodiment, the present invention provides a method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, the method comprising: providing an adsorbent material made by activating a carbonaceous material into a precursor activated carbon, the adsorbent material comprising: about 2 wt.% to about 20 wt.% nitrogen, measured based on dried precursor activated carbon; about 0.1 wt.% to about 4 wt.% iron and copper, measured based on dried precursor activated carbon; wherein the adsorbent material has a monochloramine elimination number of about 5 to about 75; and contacting the adsorbent material with a fluid.

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

[0032] In another embodiment, the water or the adsorbent material has previously undergone a disinfection step.

Implementation Method

[0033] This invention is not limited to the specific systems, apparatus, and methods described herein, as they may change depending on the environment. The terminology used herein is for the purpose of describing particular versions or embodiments only and is not intended to limit the invention. Furthermore, as described herein, any patent document listed, such as a U.S. patent, a U.S. patent application publication, a World Intellectual Property Organization publication, or a foreign patent application publication, is incorporated herein by reference in its entirety.

[0034] Unless the context clearly indicates otherwise, the singular forms "a" and "the" as used herein are intended to include the plural forms as well. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as would be understood by one of ordinary skill in the art. Nothing herein should be construed as an admission that the invention is not entitled to prior disclosure by virtue of a prior invention. As used herein, the term "comprising" means "including, but not limited to."

[0035] As used herein, the term "approximately" when applied to numerical values ​​indicates an error margin of plus or minus 10%. Therefore, approximately 50% means within the range of 45%-55%.

[0036] As used herein, the term "adsorbent material" means any material that has adsorption properties, absorption properties, or both. Adsorption properties refer to the physical binding of atoms, ions, or molecules to the surface of a material. Absorption properties refer to the entry of atoms, ions, or molecules into and retention in the bulk phase of the material. For example, adsorbent materials include activated carbon, regenerated activated carbon, natural and synthetic zeolites, silica, silica gel, alumina, zirconium oxide, and diatomaceous earth. As used herein, "adsorbent material" is a material whose composition is primarily adsorbent and / or absorbent, containing only small amounts of components that are neither adsorbent nor absorbent (e.g., a small amount of binder required for shaping activated carbon beads).

[0037] As used herein, the term "adsorbent" means any component or mixture of materials, including an adsorbent material in a mixture, blend, composite material or compound and one or more additive materials that do not have adsorption properties. For example, examples of adsorbents include an activated carbon adsorbent material mixed with a thermally conductive filler.

[0038] As used herein, the term "carbonaceous material" refers to a material containing carbon but not yet thermally or chemically activated. Carbonaceous materials may have undergone mechanical, thermal, or chemical treatment and may even possess weak adsorption properties, but they are still insufficient to adsorb compounds in large quantities like activated carbon. Examples of carbonaceous 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, oil palm nuts, peach pits, cherry pits, olive pits, walnut shells, wood, lignin, polymers, nitrogen-containing polymers, resins, petroleum bitumen, bagasse, rice husks, corn husks, wheat husks and rice husks, graphene, carbon nanotubes, or polymer fibers.

[0039] As used herein, the term "disinfection byproduct" refers to a compound whose formation results from a chemical reaction between organic and inorganic substances in the water and chemical compounds used during disinfection; or to a compound whose formation results from the radiation of organic and inorganic substances in water exposed to ultraviolet light. Examples of disinfection byproducts include one or more of chlorine, chloramine, chloroform, trihalomethanes, haloacetic acids, organic peroxides, and hydrogen peroxide. However, it is noteworthy that compounds such as disinfection byproducts may be present in water even before the disinfection process has been carried out.

[0040] As used herein, the term “macropore” refers to a pore in an adsorbent with a diameter greater than about 50 nanometers (nm).

[0041] As used herein, the term “mesoporous” refers to a pore in an adsorbent with a diameter of about 2 nanometers to about 50 nanometers.

[0042] As used herein, the term “micropore” refers to a pore in an adsorbent with a diameter of less than about 2 nanometers.

[0043] As used herein, the term "chloramine" means one or more of monochloramine (NH2Cl), dichloramine (NHCl2) or trichloramine (NCl3).

[0044] The adsorbents or adsorbent materials described herein are highly effective for removing chloroform and other volatile organic compounds (VOCs) from fluids (e.g., water). These VOCs are not limited and include one or more of the following: styrene, alachlor, atrazine, benzene, carbofuran, 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, dinoseb, endrin, ethylbenzene, vinyl dibromo (EDB), haloacetonitrs (HAN, including bromochloroacetonitrile, dibromoacetonitrile, dichloroacetonitrile, trichloroacetonitrile), haloketones (HK, including 1,1-dichloro-2-propanone and 1,1,1-trichloro-2-propanone), heptachlor (H-34, Heptox, heptachloroethylene, hexachlorobutadiene, hexachlorocyclopentadiene, lindane, chloromethanol, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-trichlorophenoxypropionic acid (2,4,5-TP, silvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, trihalomethanes (including chloroform, bromoform, dichlorobromomethane, dichlorobromomethane), or xylene. Furthermore, volatile organic compounds (VOCs) related to the drinking water sector are well-known in the industry, for example, as detailed in NSF / ANSI 53-2019, a standard established on May 6, 2019, which is incorporated herein by reference. In some examples, the removal of volatile organic compounds (VOCs) by adsorbents or adsorbent materials is determined by the removal of the individual VOCs themselves. In other embodiments, the removal of VOCs by adsorbents or adsorbent materials is determined by the removal of substitute compounds. A substitute compound is a compound with a chemical composition similar to the analyte of interest and which is present in the sample prior to preparation and analysis. Chloroform is an example of a substitute compound as described in this paragraph.

[0045] The adsorbents or adsorbent materials described herein are also highly effective for removing other contaminants (e.g., perfluorinated and polyfluoroalkyl substances (PFAS)) from water or other fluids. These PFAS compounds include one or more of the following: perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and compounds produced in the GenX process (e.g., 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propionate and heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether).

[0046] This adsorbent or adsorbent material is also highly effective in removing a wide variety of emerging contaminants from water or other fluids. These emerging contaminants include one or more of the following: meprobamate, 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.

[0047] Figure 1 shows the entire process 10 in one embodiment of the present invention. In Figure 1, a carbonaceous material is provided 20, and the carbonaceous material is activated 30 to form a precursor activated carbon. The precursor activated carbon is selectively oxidized 40, meaning that oxidation 40 is performed in some embodiments but not in others. After oxidation 40, the precursor activated carbon is then doped 50, that is, a certain amount of copper dopant, iron dopant, and nitrogen dopant are added to the precursor activated carbon to produce a doped precursor activated carbon. Next, the doped precursor activated carbon is calcined 60 by heating at a specific temperature and under specific conditions, and cooled 70 in an inert gas environment, so as not to substantially change its pore structure or cause any substantial oxidation or activation of the doped precursor activated carbon. Once calcination 60 and cooling 70 are completed, the adsorbent material of the present invention is produced. Processing of carbonaceous material

[0048] This invention provides one or more carbonaceous materials that are precursors to the final adsorbent. The carbonaceous materials may have undergone mechanical, thermal, or chemical treatment and may even possess weak adsorption properties, but they are still insufficient to adsorb compounds in large quantities like activated carbon. Furthermore, although the carbonaceous materials may have undergone mechanical, thermal, or chemical treatment, the manner in which they are treated differs from that of activated carbon. Examples of carbonaceous 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, oil palm nuts, 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 rice husks, graphene, carbon nanotubes, or polymer fibers.

[0049] In some embodiments, the carbonaceous material is coconut. Coconut carbonaceous materials are particularly useful because the activated carbon formed after coconut is activated has excellent adsorption properties for chloroform or other organic compounds.

[0050] After the carbonaceous material is provided, the process begins. Certain process steps are not limited. These unrestricted steps depend on the type of carbonaceous material and the desired form of the final activated carbon, and include one or more of the following: high-temperature pyrolysis of the carbonaceous material to form charcoal; grinding the charcoal; mixing the ground charcoal with an adhesive; pressing the ground charcoal and adhesive into blocks; crushing the blocks; sizing the crushed blocks; baking the sized blocks or the blocks themselves until carbonization, curing, or removal of the adhesive. However, in all cases, the carbonaceous material, whether in the form of baked carbon bricks or sieved granules, is subjected to thermal activation, chemical activation, or a combination of both. Thermal activation is performed by heating the baked carbon bricks or sieved granules in the presence of one or more of water, oxygen, and carbon dioxide. Chemical activation is performed by immersing the baked carbon bricks or sieved granules in a strong acid, strong alkali, or salt. It is worth noting that whether or not each of the above steps is included in the process sometimes depends on the carbonaceous material provided. For example, when the carbonaceous material is coconut, the process steps do not include "re-aggregation," and the steps include: mixing an adhesive with wood charcoal powder; pressing the wood charcoal powder and adhesive into blocks; crushing the blocks; and sieving the crushed blocks.

[0051] The result of treating this carbonaceous material is the formation of activated carbon. As described herein, this activated carbon will be referred to as "precursor activated carbon" because additional processing steps will be applied to the precursor activated carbon to further improve its performance. The performance of the precursor activated carbon involves several factors, including the type and content of one or more carbonaceous materials involved, the type of activation (including chemical or thermal activation), and the degree of activation applied to the carbonaceous material to form the precursor activated carbon. The performance of the precursor activated carbon is also affected by other processing steps, such as the crushing or sieving of the re-agglomerated carbonaceous material particles, the degree of residual binder, and the final size of the precursor activated carbon.

[0052] In all embodiments, the precursor activated carbon is not separately treated or oxidized beyond the steps described above. Therefore, the adsorbent's capacity is considerable for a wide variety of disinfection byproducts or other pollutants because the adsorption capacity of the precursor activated carbon itself is maintained and does not particularly rely on a catalytic effect. In some embodiments, due to the porous structure of the precursor activated carbon, it retains the ability to absorb substantially all organic compounds, including chloroform, volatile organic compounds (VOCs), perfluorinated and polyfluoroalkyl substances (PFAS), and emerging pollutants. Oxidation of the precursor activated carbon

[0053] This invention considers a selective oxidation method for the precursor activated carbon. In some embodiments, the precursor activated carbon is activated before being oxidized. In other embodiments, the precursor activated carbon is not oxidized after activation. Oxidation of the precursor activated carbon means that the precursor activated carbon is exposed to oxygen molecules at a sufficient temperature to apply oxygen-containing substances or complexes to the surface of the activated carbon. Oxidation does not imply a substantial modification to the pore structure of the precursor activated carbon.

[0054] For example, in some embodiments, oxidation involves exposing the raw material to an oxygen-containing environment and heating the raw material to a temperature of about 150 °C to about 1050 °C. The oxidation temperature can 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, about 750 °C to about 850 °C, or any of the endpoints, or any range of the foregoing ranges or any combination of values ​​within those ranges. In various embodiments, the oxygen-containing environment is one or more of the following: atmosphere, oxygen (O2), oxygen plasma, hydrogen peroxide (H2O2), ozone (O3), nitrogen oxides (N2O), or carbon dioxide (CO2).

[0055] In some embodiments, the oxygen-containing environment is dry and free of any moisture or substantially measurable moisture. The oxidation temperature, the choice of the oxidant, and the oxidation process do not substantially modify the pore structure of the precursor activated carbon. Therefore, if a more oxidizing oxygen-containing environment is selected, the temperature must be lowered to mitigate potential additional activation. Alternatively, if a higher temperature is selected, a less oxidizing oxygen-containing environment must be chosen to mitigate potential additional activation.

[0056] Oxidation can also be accomplished electrochemically. It is noteworthy that carbon oxidizes slowly at room temperature, in the presence or absence of humidity, and this slow oxidation is ultimately sufficient to produce carbon monoxide precursors. Alternatively, the carbon can be oxidized in a non-thermal process, for example at temperatures below about 100°C, using liquid or gaseous hydrogen peroxide, ozone, chlorine, persulfate, percarbonate, oxidizing acids (e.g., nitric acid), air, pure oxygen, or any combination thereof. In some embodiments, this oxidation step is omitted, meaning that the rate of oxidation of the adsorbent material in any step is not comparable to the aforementioned slow oxidation that occurs naturally under normal conditions at room temperature. Copper-iron-nitrogen doping.

[0057] After the precursor activated carbon has been prepared and selectively oxidized, it is further doped with a copper-iron-nitrogen compound. The copper-iron-nitrogen doping involves applying the copper-iron-nitrogen complex to the surface of the precursor activated carbon to catalyze the disinfection 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, the sources of copper, iron, and nitrogen are a single compound. In other embodiments, the sources of copper and iron are a first compound, and the source of nitrogen is a second compound. In still other embodiments, the sources of copper and nitrogen are a first compound, and the source of iron is a second compound. In still other embodiments, the sources of iron and nitrogen are a first compound, and the source of copper is a second compound.

[0058] The copper source is not limited and includes one or more of the following: copper sulfate pentahydrate (CuSO4.5H2O), copper chloride (CuCl2), copper chloride dihydrate (CuCl2.2H2O), copper nitrate (Cu(NO3)2), copper nitrate monohydrate (Cu(NO3)2.H2O), copper nitrate sesquihydrate (Cu(NO3)2.1.5H2O), copper nitrate disesquihydrate (Cu(NO3)2.2.5H2O), copper nitrate trihydrate (Cu(NO3)2.3H2O), copper nitrate hexahydrate ([Cu(H2O)6](NO3)2), copper acetate (Cu(CH3COO)2), copper acetate monohydrate (Cu(CH3COO)2H2O), copper formate tetrahydrate, Cu(NH3)6+2, basic copper carbonate (Cu2(OH)2CO3), its compounds, or mixtures or combinations thereof. In some embodiments, the copper source is supplied as part of an aqueous solution. The iron source is not limited and includes one or more of the following: ferric chloride hexahydrate (FeCl3∙6H2O), ferrous chloride tetrahydrate (FeCl2∙4H2O), ferric ammonium sulfate dodecahydrate (NH4Fe(SO4) ∙ 12H2O), ferric sulfate heptahydrate (Fe2SO4∙7H2O), ferric ammonium oxalate trihydrate ((NH4)3Fe(C2O4)3∙3H2O), ammonium hexacyanoferrate hydrate ((NH4)4[Fe(CN)6] ∙ xH2O), ferric ammonium citrate ((NH4)5[Fe(C6H4O7)2]), sodium ferrocyanide decahydrate (Na4Fe(CN)6∙10H2O), sodium ferric oxalate (Na3Fe(C2O4)3), potassium ferrocyanide trihydrate (K4[Fe(CN)6] ∙ The iron source may be 3H2O), potassium ferricyanide (K3[Fe(CN)6]), potassium ferric oxalate (K2[Fe(C2O4)2]), ferrous acetate tetrahydrate ((CH3COO)2Fe ∙ 4H2O), ferrous lactate dihydrate, ferrous lactate trihydrate, urea (CO(NH2)2), dicyandiamide (DCD), compounds thereof, or mixtures thereof, or combinations thereof. In some embodiments, the iron source is supplied as part of an aqueous solution. The nitrogen source is not limited and in some embodiments includes any source of nitrogen with an oxidation state of -3. Examples of nitrogen sources with an oxidation state of -3 include one or more urea (CO(NH2)2) or dicyandiamide (DCD), compounds thereof, mixtures thereof, or combinations thereof. In some embodiments, the nitrogen source is supplied as part of an aqueous solution. It is worth noting that anhydrous copper or iron salt precursors (including copper chloride, ferric chloride, and ferrous chloride) resemble their corresponding hydrates (including copper chloride dihydrate, ferric chloride hexahydrate, and ferrous chloride tetrahydrate) during the doping process.

[0059] Although the foregoing description of nitrogen sources, single sources combining iron or copper with nitrogen, or single sources combining copper-iron-nitrogen includes several enumerated compounds, there is no limitation on the combination of such compounds. Most notably, the applicant has found that nitrogen compounds having an oxidation state of -3 produce excellent results. Therefore, in some embodiments, the nitrogen source is not limited as long as it has an oxidation state of -3. It is generally not believed that the oxidation state of copper or iron is important to the results.

[0060] The doping process is not limited. In some embodiments, doping is performed in a single stage. In a single-stage process, the precursor activated carbon is treated by contacting it with a single solution that simultaneously contains the copper compound, the iron compound, and the nitrogen compound. For example, in one embodiment, doping in a single stage is performed by contacting the precursor activated carbon with an aqueous solution containing copper sulfate pentahydrate, ferric chloride hexahydrate, and urea. In another embodiment, doping in a single stage is performed by contacting the precursor activated carbon with an aqueous solution containing copper sulfate pentahydrate, ferric chloride hexahydrate, and dicyandiamide.

[0061] In the single-stage process of doping the precursor activated carbon, the content of the copper compound, the content of the iron compound and the content of the nitrogen compound can be controlled by one or more of the following: changing the concentration of the copper compound in the solution, changing the concentration of the iron compound in the solution, changing the concentration of the nitrogen compound in the solution, changing the contact time of the solution with the precursor activated carbon, or changing the temperature of the solution.

[0062] After the doping is completed via solution in this single-stage process, the precursor activated carbon is dried to remove moisture or other solvents, thereby leaving the copper, iron, and nitrogen compounds in the precursor activated carbon. The drying process is unrestricted and is carried out in air at a temperature of approximately 100°C to approximately 150°C for nearly 2 hours.

[0063] Following this single-stage process, the resulting doped and dried precursor activated carbon contains varying amounts of copper, iron, and nitrogen. For example, based on a dry precursor activated carbon, the added copper content 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt.% 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 comprising one or more of the above values ​​as endpoints.Based on a dry precursor activated carbon, the added iron content is approximately 0.1 wt.%, approximately 0.2 wt.%, approximately 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt. 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 comprising one or more of the above values ​​as endpoints. Based on a dry precursor activated carbon, the nitrogen content is: 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.%, approximately 11.0 wt.%, approximately 11.5 wt.%, approximately 12.0 wt.%, approximately 12.5 wt.%, approximately 13.0 wt.%, approximately 13.5 wt. wt.%, about 14.0 wt.%, about 14.5 wt.%, about 15.0 wt.%, about 15.5 wt.%, about 16.0 wt.%, about 16.5 wt.%, about 16.7 wt.%, about 17.0 wt.%, about 17.5 wt.%, about 18.0 wt.%, about 18.5 wt.%, about 19.0 wt.%, about 19.5 wt.%, about 20.0 wt.%, or any range comprising one or more of the above values ​​as endpoints.

[0064] Figure 2 shows an embodiment of the doping process 50 configured in a single stage. In this doping process 50, the precursor activated carbon is contacted with an aqueous solution containing a copper source, an iron source, and a nitrogen source, as shown in block 51. The contacted precursor activated carbon is then dried 52. After drying, the doped precursor activated carbon is ready for calcination.

[0065] In another embodiment of this single-stage process, the precursor activated carbon, after being supplied, is sprayed with an aqueous solution containing dopants such as dissolved copper sulfate pentahydrate, urea, and dissolved ferric chloride hexahydrate. The precursor activated carbon is then allowed to stand for a predetermined time. After standing, the precursor activated carbon is dried at a predetermined temperature for a predetermined time. For example, the aqueous solution contains approximately 0.19 wt.% copper, approximately 12.1 wt.% nitrogen, and approximately 0.19 wt.% iron, each of which is 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. The drying step is carried out at a temperature of approximately 100°C and lasts for approximately 4 hours, although the drying process is not limited, and these times and temperatures can be varied. Once the drying step is completed, the doped precursor activated carbon is ready for calcination.

[0066] In an alternative embodiment, doping is performed in a two-stage manner. In one two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and iron, then selectively drying the precursor activated carbon, then contacting the copper and iron-containing precursor activated carbon with a nitrogen-containing solution, and finally drying the precursor activated carbon containing copper, iron, and nitrogen. In another two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and nitrogen, then selectively drying the copper and nitrogen-containing precursor activated carbon, then contacting the copper and nitrogen-containing precursor activated carbon with an iron-containing solution, and finally drying the precursor activated carbon containing copper, iron, and nitrogen. In yet another two-stage process, the precursor activated carbon is treated by first contacting it with a solution containing copper and nitrogen, then selectively drying the copper and nitrogen-containing precursor activated carbon, then contacting the copper and nitrogen-containing precursor activated carbon with an iron-containing solution, and finally drying the precursor activated carbon containing copper, iron, and nitrogen. In another two-stage process, the precursor activated carbon is first contacted with a solution containing iron and nitrogen, then selectively dried, then contacted a copper-containing solution a second time, and finally dried with copper, iron and nitrogen.

[0067] In this embodiment, the doping is carried out in two stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper sulfate pentahydrate and an aqueous solution containing dissolved ferric chloride hexahydrate; then, the precursor activated carbon is contacted with an aqueous solution of urea. In this embodiment, the doping is carried out in two stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper sulfate pentahydrate and an aqueous solution of urea; then, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric chloride hexahydrate. In this embodiment, the doping is carried out in two stages: first, the precursor activated carbon is contacted with an aqueous solution containing dissolved ferric chloride hexahydrate and an aqueous solution of urea; then, the precursor activated carbon is contacted with an aqueous solution containing dissolved copper sulfate pentahydrate.

[0068] In another embodiment, the two-stage doping is performed by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper sulfate pentahydrate and an aqueous solution containing dissolved ferric chloride hexahydrate, and then contacting the precursor activated carbon with an aqueous solution of dicyandiamide. In another embodiment, the two-stage doping is performed by first contacting the precursor activated carbon with an aqueous solution containing dissolved copper sulfate pentahydrate and an aqueous solution of dicyandiamide, and then contacting the precursor activated carbon with an aqueous solution containing dissolved ferric chloride hexahydrate. In another embodiment, the two-stage doping is performed by first contacting the precursor activated carbon with an aqueous solution containing dissolved ferric chloride hexahydrate and an aqueous solution of dicyandiamide, and then contacting the precursor activated carbon with an aqueous solution containing dissolved copper sulfate pentahydrate.

[0069] In the two-stage process of doping the precursor activated carbon, the amount of copper compound, iron compound and nitrogen compound doped can be controlled by one or more of the following: changing the concentration of the copper compound in the solution, changing the concentration of the iron compound in the solution, changing the concentration of the nitrogen compound in the solution, changing the contact time of one or more copper-containing solutions, iron-containing solutions or nitrogen-containing solutions with the precursor activated carbon, or changing the temperature of one or more copper-containing solutions, iron-containing solutions or nitrogen-containing solutions.

[0070] After the two-stage process, the precursor activated carbon obtained after doping and drying contains specific amounts of copper, iron and nitrogen. For example, based on a dry precursor activated carbon, the copper content 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt. 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 4.3 wt.%, about 4.4 wt.%, about 4.5 wt.%.Based on a dry precursor activated carbon, the iron content is approximately 0.1 wt.%, approximately 0.2 wt.%, approximately 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt.%, approximately 2.9 wt. 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 4.3 wt.%, about 4.4 wt.%, about 4.5 wt.%, or any range comprising one or more of the above values ​​as endpoints. Based on a dry precursor activated carbon, the nitrogen content is: 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.%, approximately 11.0 wt.%, approximately 11.5 wt.%, approximately 12.0 wt.%, approximately 12.5 wt.%, approximately 13.0 wt.%, approximately 13.5 wt. wt.%, about 14.0 wt.%, about 14.5 wt.%, about 15.0 wt.%, about 15.5 wt.%, about 16.0 wt.%, about 16.5 wt.%, about 16.7 wt.%, about 17.0 wt.%, about 17.5 wt.%, about 18.0 wt.%, about 18.5 wt.%, about 19.0 wt.%, about 19.5 wt.%, about 20.0 wt.%, or any range comprising one or more of the above values ​​as endpoints.

[0071] Figure 3 shows an embodiment of the doping process 50 configured in one or two stages. In this doping process 50, the precursor activated carbon is contacted with an aqueous solution containing a copper source and an iron source, shown as block 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, shown as block 53. After contact with the aqueous solution containing the nitrogen source, the precursor activated carbon is dried 54. After this second drying step, the doped precursor activated carbon is ready to be calcined.

[0072] In an alternative embodiment, doping is performed in three stages. In one three-stage process, the precursor activated carbon is first contacted with a copper-containing solution, selectively dried, then contacted with an iron-containing solution, selectively dried, and finally contacted with a nitrogen-containing solution, and dried. In another three-stage process, the precursor activated carbon is first contacted with an iron-containing solution, selectively dried, then contacted with a copper-containing solution, selectively dried, and finally contacted with a nitrogen-containing solution, and dried. In another three-stage process, the precursor activated carbon is first contacted with a copper-containing solution for selective drying; then, it is contacted with a nitrogen-containing solution for selective drying of both copper and nitrogen-containing precursor activated carbon; finally, it is contacted with an iron-containing solution for drying. In yet another three-stage process, the precursor activated carbon is first contacted with an iron-containing solution for selective drying; then, it is contacted with a nitrogen-containing solution for selective drying of both iron and nitrogen-containing precursor activated carbon; finally, it is contacted with a copper-containing solution for drying. In another three-stage process, the precursor activated carbon is first contacted with a nitrogen-containing solution, selectively dried, then contacted with a copper-containing solution, selectively dried, and finally contacted with an iron-containing solution, and dried. In yet another three-stage process, the precursor activated carbon is first contacted with a nitrogen-containing solution, selectively dried, then contacted with an iron-containing solution, selectively dried, and finally contacted with a copper-containing solution, and dried.

[0073] In one embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, the precursor activated carbon is second contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, and the precursor activated carbon is third contacted with an aqueous solution of urea. In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, the precursor activated carbon is second contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, and the precursor activated carbon is third contacted with an aqueous solution of urea. In yet another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, the precursor activated carbon is second contacted with an aqueous solution of urea, and the precursor activated carbon is third contacted with an aqueous solution containing dissolved ferric chloride hexahydrate. In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, then with an aqueous solution of urea, and finally with an aqueous solution containing dissolved copper sulfate pentahydrate. (This process is repeated three times in the original text.)

[0074] In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, the precursor activated carbon is second contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, and the precursor activated carbon is third contacted with an aqueous solution of dicyandiamide. In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, the precursor activated carbon is second contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, and the precursor activated carbon is third contacted with an aqueous solution of dicyandiamide. In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved copper sulfate pentahydrate, the precursor activated carbon is second contacted with an aqueous solution of dicyandiamide, and the precursor activated carbon is third contacted with an aqueous solution containing dissolved ferric chloride hexahydrate. In another embodiment, doping is carried out in three stages: the precursor activated carbon is first contacted with an aqueous solution containing dissolved ferric chloride hexahydrate, then second contacted with an aqueous solution of dicyandiamide, and finally third contacted with an aqueous solution containing dissolved copper sulfate pentahydrate. (This process is repeated three times in the original text.)

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

[0076] After the three-stage process, the precursor activated carbon obtained after doping and drying contains specific amounts of copper, iron and nitrogen. For example, based on a dry precursor activated carbon, the added copper content 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt.% 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 comprising one or more of the above values ​​as endpoints.Based on a dry precursor activated carbon, the added iron content is approximately 0.1 wt.%, approximately 0.2 wt.%, approximately 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.%, approximately 2.5 wt.%, approximately 2.6 wt.%, approximately 2.7 wt.%, approximately 2.8 wt. 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 comprising one or more of the above values ​​as endpoints. Based on a dry precursor activated carbon, the added nitrogen content is as follows: 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.%, approximately 11.0 wt.%, approximately 11.5 wt.%, approximately 12.0 wt.%, approximately 12.5 wt.%, approximately 13.0 wt.%, approximately 13.5 wt. wt.%, about 14.0 wt.%, about 14.5 wt.%, about 15.0 wt.%, about 15.5 wt.%, about 16.0 wt.%, about 16.5 wt.%, about 16.7 wt.%, about 17.0 wt.%, about 17.5 wt.%, about 18.0 wt.%, about 18.5 wt.%, about 19.0 wt.%, about 19.5 wt.%, about 20.0 wt.%, or any range comprising one or more of the above values ​​as endpoints.

[0077] Although the single-stage, two-stage, and three-stage copper-iron-nitrogen doping processes are disclosed above, these processes are not limited. For example, additional dopants may be applied via additional steps or as part of any solution to contact the precursor activated carbon.

[0078] There is no limitation on the ratio of iron to copper. 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 falling within the foregoing ranges. Heat treatment / calcination

[0079] After completing one or more of the single-stage, two-stage, and three-stage copper-iron-nitrogen doping procedures, the doped precursor activated carbon is prepared for heat treatment, also known as calcination. During calcination, the doped precursor activated carbon is heated in an inert gas environment to achieve additional changes in the doped precursor activated carbon.

[0080] There is no limitation on the calcination temperature of the doped precursor activated carbon. In some embodiments, calcination occurs 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 about 900°C to about 1000°C.

[0081] The inert gas environment for calcination refers to a gaseous environment at a specific temperature that does not cause any substantial oxidation or activation of the doped precursor activated carbon, so that the pore structure of the doped precursor activated carbon remains unchanged. Therefore, in many embodiments, the gaseous environment does not contain oxygen, carbon dioxide, or water, or the amount of oxygen, carbon dioxide, or water contained in the gaseous environment is insufficient to cause any oxidation or activation. Examples of gaseous environments for calcination include one or more of the following: nitrogen (N2), helium, neon, argon, krypton, xenon, and their components. After the calcination step is completed, the product obtained is the adsorbent material.

[0082] In some embodiments, the adsorbent material is granular activated carbon (GAC), which by definition refers to activated carbon particles that would be retained when arranged in a 50-mesh sieve (approximately 0.300 mm in pore size). In other embodiments, the adsorbent material is powdered activated carbon (PAC), which by definition refers to activated carbon particles that can pass through an 80-mesh sieve (approximately 0.180 mm in pore size). Although these particle size ranges are illustrative of activated carbon adsorbent materials, it is conceivable that any disclosed adsorbent material would also be suitable for use with the aforementioned 50-mesh and 80-mesh sieve sizes as a benchmark. In yet another embodiment, the adsorbent material is pellet-shaped activated carbon. Performance Measurement / Adsorbent Characteristics

[0083] The effectiveness of the adsorbent material of the present invention can be measured in various ways, including by the chloramine removal number (CDN), which will be defined as follows. The chloramine removal number can be used to quantify the amount of chloramine that can be removed from a fluid using the adsorbent material of the present invention. The method of measuring the chloramine removal number is well known in the art, for example, U.S. Patent No. 10,702,853, issued on July 7, 2020, entitled "CHLORAMINE AND CHLORINE REMOVAL MATERIAL AND METHODS FOR MAKING THE SAME", the entire contents of which are incorporated herein by reference.

[0084] The chloramine elimination number refers to the absolute value of a first-order linear kinetic fit obtained by taking the natural logarithm of the relationship between the initial concentration of chloramine in water and time over a period of 150 minutes, multiplied by 1000. When ammonia reaches equilibrium with chlorine in an aqueous solution, the form of chloramine depends on the pH value. The chloramine solution contains ammonium chloride; sodium hypochlorite and deionized water are mixed to obtain a 1 L, 300 ppm chloramine solution with a pH of 9.0. At pH 9.0, the chloramine substance exists in the form of monochloramine at equilibrium, which is the most difficult to eliminate. The solution is buffered with sodium carbonate to maintain the pH value of the solution during estimation. The chlorine solution contains sodium hypochlorite and deionized water to obtain a 1 L, 300 ppm chlorine solution. The corresponding 1 L, 300 ppm solutions are added to a conical flask placed in a water bath at a controlled temperature of 20°C. Activated carbon (sieved to 80×325 mesh) was added in a fixed volume of 2.0 mL to a 1 L solution of chloramine or chlorine under stirring for sample analysis. The volume of carbon used was determined by the apparent density of the 80x325 carbon according to ASTM D-2854. The total chlorine concentration in the solution was measured at multiple time points using equal aliquots over a 150-minute period, followed by analysis using the HACH standard colorimetric method conforming to US EPA Regulation 10070.

[0085] After experimental analysis of an adsorbent material, the natural logarithm of the concentration versus time data for each adsorbent material sample is taken to reconstruct a linear relationship between the total chlorine concentration and time according to first-order kinetics. Then, a linear fit is performed on this data, and the slope of the linear fit is determined. Because the initial concentration of total chlorine gradually decreases over 150 minutes, the slope is always negative. Therefore, the absolute value of this slope multiplied by 1000 is used to quantify the elimination (removal) rate of chloramines and chlorine. The larger the absolute value of the slope, the more effectively the adsorbent material removes chlorine and chloramines. For these measurements, the slope obtained from the linear fit of the first-order kinetic experimental data (multiplied by 1000) is called the "chloramine elimination number," or simply CDN. In the case of chlorine removal, this rate refers to the "chlorine elimination number," or simply Cl-DN. The adsorbent material or adsorbent of the present invention can then use these values ​​to determine the amount of chloramines and / or chlorine it removes from water.

[0086] In addition to chloramine, the present invention is also effective in removing chlorine from fluids (e.g., water flow). The ability of calcined activated carbon to remove chlorine can be evaluated as described above; however, the test solution was prepared without the addition of ammonium chloride, and therefore contained 300 ppm of chlorine. 95% of the adsorbent material used for chlorine analysis had a particle size of approximately 325 mesh. The analysis of chlorine concentration versus time data and the corresponding first-order dynamic slope remained the same; however, the slope of the linear fit of this data is called the "chlorine removal number," or Cl-DN for short, which can also be used to determine the amount of chlorine that the adsorbent material or adsorbent of the present invention can remove from water.

[0087] The values ​​envisioned for the chloramine elimination number in this invention are approximately 3.0, approximately 3.5, approximately 4.0, approximately 4.5, approximately 5.0, approximately 5.5, approximately 6.0, approximately 6.5, approximately 7.0, approximately 7.5, approximately 8.0, approximately 8.5, approximately 9.0, approximately 9.5, approximately 10.0, approximately 10.5, approximately 11.0, approximately 12.0, approximately 12.5, approximately 13.0, approximately 13.5, approximately 14.0, approximately 14.5, approximately 15.0, approximately 15.5, approximately 16.0, approximately 16.5, approximately 17.0, approximately 17.5, approximately 18.0, approximately 18.5, approximately 19.0, approximately 19.5, approximately 20.0, approximately 20.5, approximately 21.0, approximately 21.5, approximately 22.0, approximately 22.5, approximately 23.0, approximately 2 3.5, about 24.0, about 24.5, about 25.0, about 25.5, about 26.0, about 26.5, about 27.5, about 28.0, about 28.5, about 29.0, about 29.5, about 30.0, about 35.0, about 40.0, about 45.0, about 50.0, about 55.0, about 60.0, about 65.0, about 70.0, about 75.0, about 80.0, about 85.0, about 90.0, about 95.0, about 100.0, about 105.0, about 110.0, about 115.0, about 120.0, about 125.0, about 130.0, about 135.0, about 140.0, about 145.0, about 150.0, or any range containing at least two of these values ​​as endpoints. Alternatively, the chloramine elimination number can be a range of numbers that serve as the lower limit of efficacy, 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 elimination number refers to the measurement of monochloramine.

[0088] The "peroxide elimination number" (also known as "peroxide number") is also measured. The peroxide number is a volumetric determination, meaning that its effectiveness is measured and normalized relative to a specific capacity of adsorbent material. The determination of peroxide number is well known and detailed in, for example, U.S. Patent No. 5,470,748, the entire contents of which are incorporated herein by reference.

[0089] During the peroxide number determination, the adsorbent material was first pulverized into a fine mesh size, wherein at least 90 wt.% (and at least 95 wt.% in a specific test) of the adsorbent passed through a 325-mesh American Standard Series sieve (44 µm opening size). A specific amount of the pulverized adsorbent material was placed in a vacuum flask (Dewar flask), and 100 mL of deionized water was added to the vacuum flask. The deionized water was added so that any portion of the pulverized adsorbent material adjacent to the side of the vacuum flask would be carried into the water mass at the bottom of the vacuum flask. Next, a 50 mL aliquot of a buffer solution was added to the vacuum flask. The buffer solution contained 0.5 moles of dipotassium hydrogen phosphate (K₂HPO₄) and 0.5 moles of potassium dihydrogen phosphate (KH₂PO₄). After adding the buffer solution, a magnetic stir bar was added to the vacuum flask and stirred. The stirring speed is gradually increased until the depth of a vortex formed in the mixture is greater than about 0.5 inches (1.27 cm), which is the optimal stir bar speed. The optimal stir bar speed is selected so that additional stirring bar speed does not significantly affect the decomposition time of the peroxide.

[0090] As described in the preceding paragraph, during the determination of the peroxide number, a specific amount of adsorbent material was added to a buffered hydrogen peroxide solution. Since the test is a volumetric determination, the amount of adsorbent material added to the buffered hydrogen peroxide solution is based on half (1 / 2) of the apparent density of the adsorbent material. Specifically, the mass of the adsorbent material added to the solution, in grams, is equal to half (1 / 2) of the measured apparent density of the adsorbent material, which is expressed in g / cm³. In the buffer solution, the catalytic properties of the adsorbent material cause the peroxide to be catalyzed and thus eliminated (i.e., the hydrogen peroxide decomposes into water and oxygen).

[0091] The catalysis of peroxides is an exothermic reaction. Therefore, the decomposition rate based on the adsorbent material can be estimated over time by measuring the temperature of the buffer solution. As used herein, "peroxide number" is the length of time, expressed in minutes, required for the buffer solution containing the sample of the adsorbent material to reach 75% of the highest recorded temperature. A faster time and a lower peroxide number indicate greater catalytic activity, and therefore higher efficiency of the adsorbent material. In some embodiments, the peroxide elimination count in minutes is: about 1.0, about 1.5, about 2.0, about 2.1, about 2.2, about 2.3, about 2.4, about 2.5, about 2.6, about 2.7, about 2.8, about 2.9, about 3.0, about 3.1, about 3.2, about 3.3, about 3.4, about 3.5, about 3.6, about 3.7, about 3.8, about 3.9, about 4.0, about 4.1, about 4.2, about 4.3, about 4.4, about 4.5, about 4.6, about 4.7, about 4.8, about 4.9, about 5.0, about 5.1, about 5.2, about 5.3, about 5.4, about 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 7.5, Approximately 7.8, Approximately 7.9, Approximately 8.0, Approximately 8.1, Approximately 8.2, Approximately 9.3, Approximately 9.4, Approximately 9.5, Approximately 9.6, Approximately 9 7, about 9.8, about 9.9, about 10.0, about 10.1, about 10.2, about 10.3, about 10.4, about 10.5, about 10.6, about 10.7, about 10.8, about 10.9, about 11.0, about 11.1, about 11.2, about 11.3, about 11.4, about 11.5, about 11.6, about 11.7, about 11.8, about 11.9, about 12.0, about 12.1, about 12.2, about 12.3, about 12.4, about 12.5, about 12.6, about 12.7, about 12.8, about 12.9, about 13.0, about 13.1, about 13. 2. Approximately 13.3, Approximately 13.4, Approximately 13.5, Approximately 13.6, Approximately 13.7, Approximately 13.8, Approximately 13.9, Approximately 14.0, Approximately 14.1, Approximately 14.2, Approximately 14.3, Approximately 14.4, Approximately 14.5, Approximately 14.6, Approximately 14.7, Approximately 14.8, Approximately 14.9, Approximately 15.0, Approximately 15.1, Approximately 15.2, Approximately 15.3, Approximately 15.4, Approximately 15.5, Approximately 15.6, Approximately 15.7, Approximately 15.8, Approximately 15.9, Approximately 16.0, Approximately 16.1, Approximately 16.2, Approximately 16.3, Approximately 16.4, Approximately 16.5, Approximately 16.6, Approximately 16.7. Approximately 16.8, approximately 16.9, approximately 17.0, approximately 17.1, approximately 17.2, approximately 17.3, approximately 17.4, approximately 17.5, approximately 17.6, approximately 17.7, approximately 17.8, approximately 17.9, approximately 18.0, approximately 18.1, approximately 18.2, approximately 18.3, approximately 18.4, approximately 18.5, approximately 18.6, approximately 18.7, approximately 18.8, approximately 18.9, approximately 19.0, approximately 19.1, approximately 19.2, approximately 19.3, approximately 19.4, approximately 19.5, approximately 19.6, approximately 19.7, approximately 19.8, approximately 19.9, approximately 20.0, or any range formed by two or more of the above values ​​as end values ​​of the range. In some embodiments, the peroxide elimination count 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 values ​​as endpoints of the range.

[0092] This peroxide number relates to and relates to the chloramine elimination number (CDN) and the chlorine elimination number (Cl-DN), each of which is an indicator of the catalytic activity of the adsorbent material. However, this correlation is not always definitive, as each represents a different aspect of the catalytic activity of an adsorbent material. Furthermore, this catalytic activity is only useful for those compounds that will be catalyzed; other compounds must be adsorbed to be effectively removed from a liquid stream. Therefore, a superior adsorbent material must possess good performance in more than one of the chloramine elimination number (CDN), chlorine elimination number (Cl-DN), peroxide number, and various adsorption tests to effectively remove a wide range of compounds from the liquid stream. Fluid Processing

[0093] Further embodiments relate to methods for purifying fluids (e.g., water) using the aforementioned adsorbent material for eliminating chlorine and chloramines. In one embodiment, fluid treatment includes: passing the fluid through a bed of adsorbent material, introducing the fluid into a filter containing the adsorbent material, introducing the adsorbent material into a container holding the fluid, etc. In some embodiments, the above steps are combined and performed simultaneously or sequentially. 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.

[0094] In other embodiments, the method for purifying the fluid includes additional steps. For example, in some embodiments, the purification method includes a step of filtering the fluid, which involves removing particulate matter using a tool such as a sieve or sand filter before, after, or before and after contact with the adsorbent material. In other embodiments, the method includes a step of disinfecting the water to remove biological contaminants, such as bacteria or other microorganisms, and in some embodiments, the method includes a step of introducing a disinfectant into the fluid or irradiating the fluid with ultraviolet light. In still other embodiments, the method includes steps such as purifying the fluid, adjusting the pH of the fluid, and combinations thereof. In each of the above embodiments, the fluid may be water. Example

[0095] The following experimental examples are only for better illustrating specific embodiments and are not intended to limit the scope of the invention. Single-stage program example

[0096] Coconut carbonaceous material is provided and processed and activated. The resulting coconut activated carbon is available from Calgon Carbon Corporation, whose product name is OLC, and is referred to as precursor activated carbon. This coconut activated carbon is a granular activated carbon and has undergone a size test of 12 × 40. The precursor activated carbon is oxidized in some tests and not oxidized in others. After the preparation of the precursor activated carbon and the selective oxidation step (in some examples), the precursor activated carbon is ready to be doped with copper, iron, and nitrogen.

[0097] The doping of copper, iron, and nitrogen is carried out in a single-stage doping process. This single-stage doping process dops the oxidized or unoxidized precursor activated carbon with copper, iron, and nitrogen. During this single-stage doping process, an aqueous solution containing copper sulfate pentahydrate, ferric chloride hexahydrate, and urea is contacted with the oxidized or unoxidized precursor activated carbon to achieve a copper content of 0.2 wt.% to 1.0 wt.%, an iron content of 0.2 wt.% to 1.0 wt.%, and a nitrogen content of 2.2 wt.% to 8.3 wt.%, up to 15 wt.%, on the carbon (based on dried precursor activated carbon). The aqueous solution is contacted with the precursor activated carbon at 25°C for approximately 30 minutes. After the aqueous solution contacts the precursor activated carbon, the precursor activated carbon is dried to generate a doped precursor activated carbon.

[0098] The doped precursor activated carbon was ultimately calcined. During calcination, the doped precursor activated carbon was heated to 950°C in a pure nitrogen atmosphere for one hour. Experimental Results

[0099] Figure 4 shows the effect of changes in nitrogen content on chloramine scavenging number and peroxide number, where nitrogen is doped into the precursor activated carbon and the total metal level is maintained at approximately 0.5 wt.%. The results shown in Figure 4 are for precursor activated carbon derived from coconut carbonaceous material followed by oxidation. The added copper, iron, and nitrogen are doped into this oxidized activated carbon. Figure 4 shows that for a total metal loading level of 0.5 wt.%, there is no significant increase in chloramine scavenging number and peroxide scavenging number after doping with approximately 4 wt.% nitrogen.

[0100] Figures 5 and 6 show the effect of metal doping of the precursor activated carbon on the chloramine elimination number and peroxide number. The precursor activated carbon is derived from coconut carbonaceous material, oxidized, and doped with copper, iron, and nitrogen. Compared to precursor activated carbon doped with copper and iron or iron and nitrogen (derived from coconut carbonaceous material), this precursor activated carbon doped with copper, iron, and nitrogen achieves a higher chloramine elimination number. This copper, iron, and nitrogen doping also achieves a faster (and therefore better) peroxide elimination number compared to copper and iron or iron and nitrogen doping.

[0101] Figure 7 shows a comparison of the effects of changes in nitrogen content on chloramine elimination number and peroxide number. The nitrogen content is added to the oxidized precursor activated carbon, and the total metal levels in copper-nitrogen, iron-nitrogen, and copper-iron-nitrogen are kept at approximately 0.5 wt.%.

[0102] Figure 8 shows the effect of nitrogen content changes on chloramine elimination number and peroxide number. The nitrogen content is added to unoxidized precursor activated carbon, which is derived from coconut carbonaceous material and doped with copper, iron, and nitrogen, maintaining a total metal level of approximately 0.5 wt.%. Figure 8 shows that for a total metal loading level of 0.5 wt.%, the chloramine elimination number increases linearly with the addition of more nitrogen to the carbon. Conversely, the peroxide elimination number decreases with the addition of more nitrogen to the carbon.

[0103] Figures 9 and 10 show the effects of adding metal loading to the carbon on the chloramine elimination number and peroxide number, respectively. The precursor activated carbon is derived from coconut carbonaceous material, is unoxidized, and is doped with copper, iron, and nitrogen. Compared to unoxidized precursor activated carbon doped only with copper and nitrogen or iron and nitrogen, this unoxidized precursor activated carbon doped with copper, iron, and nitrogen achieves a higher chloramine elimination number. Compared to unoxidized precursor activated carbon doped only with copper and nitrogen or iron and nitrogen, this unoxidized precursor activated carbon doped with copper, iron, and nitrogen achieves a faster peroxide elimination number.

[0104] Table 1 compares unoxidized precursor activated carbon derived from wood-based carbonaceous materials, doped with copper-nitrogen, iron-nitrogen, and copper-iron-nitrogen. A peroxide number greater than 60 indicates that no temperature peak was observed after a 60-minute test period, and that the actual peroxide number exceeded 60 minutes. This implies poor performance of the metric system. BGE is a granular wood-based activated carbon available from Calgon Carbon. AquaGuard® is a wood-based catalyst activated carbon used to remove chlorine and chloramines from drinking water and is available from Ingevity, North Charleston, South Carolina. Table 1 Sample Description Added metals (wt.%) Added nitrogen (wt.%) Calcination time (min) Calcination temperature (°C) Apparent density (g / cm³) 3 ) chloramine elimination number Hydrogen peroxide (min) AquaGuard® -- -- -- -- 0.313 3.5 63.4 BGE (unoxidized raw materials) -- -- -- 950 0.270 2.0 >60 BGE (copper-iron-nitrogen, 50:50 copper-iron) 0.25 9.5 60 950 0.297 8.1 12.4 BGE (Urea Only) -- 9.5 60 950 0.294 2.0 96.6 BGE (copper only) 0.25 -- 60 950 0.283 2.7 >60 BGE (Iron Only) 0.25 -- 60 950 0.287 2.2 >60

[0105] In the foregoing description, the reference numerals are for the accompanying drawings and form part of this document. In the drawings, unless specifically indicated herein, similar symbols generally identify similar components. The illustrative embodiments in the description of the embodiments, the brief illustrations in the drawings, and the claims are not intended to be limiting. Other embodiments and modifications may be used without departing from the spirit or scope presented herein. It will be readily understood that, as generally described herein and illustrated in the drawings, various configurations of the invention can be adopted, replaced, combined, and designed in various ways, all of which are contemplated and are part of this invention.

[0106] This invention is not limited to the specific embodiments described in this application, but is intended to illustrate various different forms. Those skilled in the art will understand that various modifications and variations can be made to the methods and structures described above without departing from their spirit and scope. In addition to those listed herein, those skilled in the art will readily understand, upon referring to the foregoing description, that functionally equivalent methods and apparatus also fall within the scope of this invention. These modifications or variations are intended to fall within the scope of the appended patent protection. This invention is limited only by the terms of the appended claims and may claim the equivalent scope of those claims. It should be understood that this invention is not limited to specific methods, reagents, compounds, components, or biological systems, all of which are naturally subject to change. It should also be understood that the terminology used herein is merely illustrative of specific embodiments and is not intended to limit the invention.

[0107] For most of the plural and / or singular terms used in this article, those familiar with this technique can translate plural to singular, or vice versa, as long as it is appropriate to the context and / or the grammar. For the sake of brevity, various singular / plural substitutions can be clearly expressed here.

[0108] Those skilled in the art will understand that, generally, especially in subsequent appended claims (e.g., the subject of the claims), the terms used herein are generally intended to be "open-ended" (e.g., the term "comprising" should be interpreted as "including but not limited to"; the term "having" should be interpreted as "having at least"; and the term "including" should be interpreted as "including but not limited to," etc.). Although various components, methods, and apparatuses are defined by "comprising" different components or steps (which should be interpreted as "including but not limited to"), these components, methods, and apparatuses can also be "consistently composed of (the various components and steps)" or "composed of (the various components and steps)," and these terms should be interpreted to define a group of substantially closed components. Those skilled in the art will also understand that if a particular value recorded in an introductory claim is intentional, then that intention will be explicitly stated in the claim; otherwise, if such a statement is not made, such intention does not exist.

[0109] For example, to aid understanding, the following appended claim may contain the use of the introductory phrases "at least one" and "one or more" to guide the claim statement. However, the use of such phrases should not be construed as implying that the introduction of a claim statement by the indefinite article "one" would cause any particular claim statement containing this introductory claim statement to be limited to an embodiment containing only one such statement, even when the same claim statement contains the introductory phrase "one or more" or "at least one" and an indefinite article (e.g., "one") (for example, "one" should be interpreted as meaning "at least one" or "one or more"); the same applies to the case where a claim statement is introduced by a definite article.

[0110] Furthermore, even if a specific numerical value is explicitly stated in an introductory claim, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the numerical value of that statement (e.g., the simple statement "two statements" without any other modifiers means "at least two statements" or "two or more statements"). Moreover, when idioms such as "at least one of A, B, and C" are used, this is generally intended to express that those skilled in the art will understand the idiom (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, a system having a single A, a single B, a single C, both A and B, both A and C, both B and C, and / or all three A, B, and C). In cases similar to "A, B, or..." When the idiom "at least one of A, B, or C" is used, it is generally intended to express that a person skilled in the art would understand the idiom (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, having only A, only B, only C, both A and B, both A and C, both B and C, and / or all three of A, B, and C). A person skilled in the art will further understand that, whether in the specification, the claims, or the drawings, almost any disjointed word and / or phrase presenting two or more alternative terms should be understood to envision a multitude of possibilities including one, any, or both terms. For example, the phrase "A or B" would be understood to include all possibilities of "A" or "B" or "A and B".

[0111] Furthermore, when features or aspects of the invention are described in the manner of the Markus group, those skilled in the art will recognize that the invention is therefore defined as a single element or a subgroup of elements of the Markus group.

[0112] As those skilled in the art will understand, for any and all purposes, such as by providing a written description, all scopes described herein also encompass any and all possible subscopes and combinations thereof. Any listed scope can be readily considered sufficiently descriptive, and such that the same scope can be decomposed into at least two, three, four, five, ten, etc., equal parts. As a non-limiting example, each scope discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc. As those skilled in the art will also understand, all terms such as "up to," "at least," etc., include the stated numerical values ​​and refer to a scope that can subsequently be decomposed into subscopes as described above. Finally, as those skilled in the art will understand, a scope includes each individual component. 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, and so on.

[0113] The various contents and other features and functions, or alternatives thereof, may be incorporated into many other different systems or applications. Those skilled in the art may subsequently make various alternatives, modifications, variations or improvements thereto that are not currently seen or foreseen, and each is intended to be included in the embodiments of the present invention. [Simplified Explanation of the Diagram]

[0115] Various aspects, features, and advantages of embodiments of the present invention will become clearer from the following description and from the accompanying claims and figures, wherein:

[0116] Figure 1 illustrates a process of one embodiment.

[0117] Figure 2 illustrates a process of one embodiment.

[0118] Figure 3 illustrates a process of one embodiment.

[0119] Figure 4 shows the relationship between the chloramine elimination number and peroxide number of OLC doped with copper-iron-nitrogen and the change in nitrogen content.

[0120] Figure 5 shows the relationship between the chloramine elimination number of oxidized OLC and the added metal load.

[0121] Figure 6 shows the relationship between the peroxide number of oxidized OLC and the added metal load.

[0122] Figure 7 shows the relationship between the chloramine elimination number of OLCs that have been oxidized and doped with copper-iron, iron-nitrogen or copper-iron-nitrogen and the amount of nitrogen added.

[0123] Figure 8 shows the relationship between the chloramine elimination number and peroxide number of unoxidized OLC doped with copper-iron-nitrogen and the change in nitrogen content.

[0124] Figure 9 shows the relationship between the chloramine elimination number of unoxidized OLC and the increased metal loading.

[0125] Figure 10 shows the relationship between the peroxide number of oxidized OLC and the increased metal load.

Claims

1. An adsorbent material, which is made by activating a carbonaceous material to form a precursor activated carbon, the adsorbent material comprising: about 4 wt.% to about 20 wt.% nitrogen, measured based on dried precursor activated carbon; about 0.1 wt.% to about 1 wt.% iron, measured based on dried precursor activated carbon; and about 0.1 wt.% to about 1 wt.% copper, measured based on dried precursor activated carbon; wherein the weight ratio of iron to copper is about 50:50; wherein, The adsorbent material has a monochloramine elimination number, which is approximately 5 to approximately 75.

2. The adsorbent material as claimed in claim 1, wherein the chloramine elimination number is about 20 to about 75.

3. The adsorbent material of claim 1, wherein the adsorbent material has a peroxide elimination number of less than about 20 minutes.

4. The adsorbent material as claimed in claim 3, wherein the adsorbent material has a peroxide elimination number of about 1 minute to about 10 minutes.

5. The adsorbent material of claim 1, wherein the nitrogen content is between about 4 wt.% and about 5 wt.%.

6. The adsorbent material of claim 1, wherein the nitrogen content is between about 10 wt.% and about 20 wt.%.

7. The adsorbent material of claim 1, wherein the adsorbent material is made of a carbonaceous material derived from one or more of coal, wood and coconut.

8. The adsorbent material of claim 7, wherein at least a portion of the carbonaceous material is derived from coconut.

9. A method for manufacturing an adsorbent material as claimed in claim 1, the method comprising: Provide a carbonaceous material; The carbonaceous material is activated to form a precursor activated carbon. The precursor activated carbon is selectively oxidized; The precursor activated carbon is doped by contacting it with one or more compounds, which are a copper source, an iron source, and a nitrogen source, to form a doped precursor activated carbon; the doped precursor activated carbon is calcined by heating it in a calcining environment to raise the temperature to at least about 950°C, during which no substantial oxidation or activation occurs in the doped precursor activated carbon, thereby forming the adsorbent material as claimed in claim 1.

10. The method of claim 9, wherein the copper source, the iron source and the nitrogen source are a single compound.

11. The method of claim 9, wherein the copper source and the iron source are a first compound, and the nitrogen source is a second compound.

12. The method of claim 9, wherein the copper source and the nitrogen source are a first compound, and the iron source is a second compound.

13. The method of claim 9, wherein the iron source and the nitrogen source are a first compound, and the copper source is a second compound.

14. The method of claim 9, wherein the copper source is a first compound, the iron source is a second compound, and the nitrogen source is a third compound.

15. The method of claim 9, wherein the doping of the precursor activated carbon is performed in a single-stage process, the single-stage process comprising: The precursor activated carbon is brought into contact with an aqueous solution containing the copper source, the iron source and the nitrogen source.

16. As in request item 9, wherein: The copper source is one or more of the following: copper sulfate pentahydrate, copper chloride, copper chloride dihydrate, copper nitrate, copper nitrate monohydrate, copper nitrate sesquihydrate, copper nitrate disesquihydrate, copper nitrate trihydrate, copper nitrate hexahydrate, copper acetate, copper acetate monohydrate, copper formate tetrahydrate, Cu(NH3)6+2, basic copper carbonate, their compounds or mixtures thereof; The iron source is one or more of the following: ferric chloride hexahydrate, ferrous chloride tetrahydrate, ferric ammonium sulfate dodecahydrate, ferric sulfate heptahydrate, ferric ammonium oxalate trihydrate, ammonium hexacyanoferrate hydrate, ferric ammonium citrate, sodium ferrous cyanide decahydrate, sodium ferric oxalate, potassium ferrous cyanide trihydrate, potassium ferric cyanide, potassium ferric oxalate, ferrous acetate tetrahydrate, ferrous lactate dihydrate, ferrous lactate trihydrate, their compounds or mixtures thereof; and the nitrogen source is one or more compounds wherein the oxidation state of nitrogen is -3.

17. The method of claim 9, wherein the calcination is carried out in a nitrogen atmosphere at a temperature of about 950°C to about 1050°C.

18. The method of claim 9, wherein the oxidation step is required and performed.

19. The method of request item 9, wherein the oxidation step is not performed.

20. The method of claim 16, wherein the copper source is copper sulfate pentahydrate, the iron source is ferric chloride hexahydrate, and the nitrogen source is one or more of urea or dicyandiamide.

21. The method of claim 17, wherein the calcination is carried out in a nitrogen atmosphere at a temperature of about 950°C to about 975°C.

22. A method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, the method comprising: Provide the adsorbent material as requested in item 1; And to bring the adsorbent material into contact with a fluid.

23. The method of claim 22, wherein the fluid is liquid water.

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

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