Copper and nitrogen-treated adsorbents and methods for producing the same

Abstract

The carbonaceous material that is activated to form the precursor activated carbon is further improved by doping with copper and nitrogen and calcination. The resulting adsorbent has excellent catalytic properties that are useful in the field of fluid purification.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 072,531, filed on August 31, 2020, the entire content of which is incorporated herein by reference.

[0002] Fluids, such as water, are regularly disinfected by adding oxidizing compounds, irradiating the water with ultraviolet light, or both. These techniques are effective in disinfecting water, but the disinfected water often contains the oxidizing compounds themselves, the products when the oxidizing compounds dissolve in water, or the reaction compounds resulting from the irradiation of water containing various component compounds. In summary, these various compounds include chlorine, chloramine, chloroform, trihalomethanes, haloacetic acids, and hydrogen peroxide. Furthermore, in some cases, these compounds may be present in water even when the water has not been disinfected. These compounds are undesirable because they can change the odor and taste of water, cause health problems, and cause corrosion of water mains and water pipes.

[0003] Adsorbents are used to remove these compounds. Adsorbents absorb and adsorb a variety of compounds. In particular, the pores of the adsorbent enable the adsorption of compounds. However, pure adsorbents are inefficient and adsorb only a fraction of the compounds that need to be removed. To increase their effectiveness, adsorbents are sometimes treated with compounds to form catalytic adsorbents. The catalytic species is usually present on the surface of the adsorbent particles and functions by catalyzing the chemical decomposition of undesirable compounds that are poorly adsorbed or absorbed on the adsorbent. By utilizing both adsorption and catalytic mechanisms, catalytic adsorbents are far more efficient than pure, untreated adsorbents. Catalytic adsorbents have been demonstrated to be effective in removing chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, and hydrogen peroxide from water and other fluids. Nevertheless, there remains a continuing need to improve the various processes involved in forming such catalytic adsorbents and thereby improve the overall performance of adsorbents. 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[0004] The carbonaceous material, which is activated to form precursor activated carbon, is further improved by doping with copper and nitrogen, as well as by calcination. The resulting adsorbent has excellent catalytic properties that are useful in the field of fluid purification.

[0005] In one embodiment, there is a method for producing an adsorbent, which includes supplying a carbonaceous material, activating the carbonaceous material to form a precursor activated carbon, doping the precursor activated carbon by contacting it with a copper source and a nitrogen source to form doped precursor activated carbon, and calcining the doped precursor activated carbon in a calcination atmosphere that does not cause any substantial oxidation or activation of the doped precursor activated carbon to form an adsorbent.

[0006] In another embodiment, the copper source is selected from copper sulfate pentahydrate, CuSO4·5H2O, or copper(II) carbonate hydroxide, CuCO3(OH)2, and the nitrogen source is one or more of urea, CO(NH2)2, ammonium carbonate, (NH4)2CO3, or aqueous solution of ammonium hydroxide, NH4OH (nominal 28 wt% aqueous solution).

[0007] In another embodiment, the copper source is selected from copper sulfate pentahydrate, CuSO4·5H2O, and the nitrogen source is urea, CO(NH2)2.

[0008] In another embodiment, the copper source is copper(II) carbonate hydroxide, CuCO3(OH)2, and the nitrogen source is one or more of urea, CO(NH2)2, ammonium carbonate, (NH4)2CO3, or aqueous solution of ammonium hydroxide, NH4OH (nominal 28 wt% aqueous solution).

[0009] In another embodiment, calcination is carried out in an N2 atmosphere at a temperature of approximately 850°C to approximately 1050°C.

[0010] In another embodiment, oxidation is required and carried out.

[0011] In another embodiment, doping of the precursor activated carbon is carried out in a one-step process, i.e., a single step of contacting the precursor activated carbon with both a copper source and a nitrogen source.

[0012] In another embodiment, contacting the precursor activated carbon with a copper source and a nitrogen source is carried out using a single aqueous solution containing both the copper source and the nitrogen source.

[0013] In another embodiment, the precursor activated carbon is dried after being in contact with a single aqueous solution containing a copper source and a nitrogen source.

[0014] In another embodiment, calcination is carried out in an N2 atmosphere at a temperature of about 600°C to about 1000°C.

[0015] In another embodiment, calcination is carried out in an N2 atmosphere at a temperature of about 700°C to about 1000°C.

[0016] In another embodiment, calcination is carried out in an N2 atmosphere at a temperature of approximately 850°C to approximately 1000°C.

[0017] In another embodiment, the method further comprises oxidizing the precursor activated carbon before doping.

[0018] In another embodiment, the method further comprises oxidizing the precursor activated carbon before doping.

[0019] In one embodiment, there is a method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, which includes providing an adsorbent comprising activated carbon doped with copper and nitrogen, and bringing the adsorbent into contact with the fluid.

[0020] In another embodiment, the fluid is liquid water.

[0021] In another embodiment, the water or adsorbent has previously undergone a disinfection process.

[0022] In another embodiment, the adsorbent is formed from a carbonaceous material that is activated to form a precursor activated carbon, the adsorbent containing about 2% to about 15% by weight of nitrogen and about 0.25% to about 2% by weight of copper as measured on a dry precursor activated carbon basis, and the adsorbent has a chloramine decomposition value (CDN) of at least about 6.

[0023] In another embodiment, there is an adsorbent formed from a carbonaceous material that is activated to form a precursor activated carbon, the adsorbent containing about 2% to about 15% by weight of nitrogen and about 0.25% to about 2% by weight of copper as measured on a dry precursor activated carbon basis, and the adsorbent has a chloramine decomposition value (CDN) of at least about 6.

[0024] In another embodiment, the CDN is approximately 6 to 60.

[0025] In another embodiment, the adsorbent is made of a carbonaceous material formed from one or more of coal, wood, and coconut.

[0026] In another embodiment, at least some of the carbonaceous material is formed from coconut. [Brief explanation of the drawing]

[0027] The aspects, features, benefits, and advantages of the embodiments described herein will be apparent with respect to the following description, the appended claims, and the appended drawings.

[0028] [Figure 1] Figure 1 shows a process according to one embodiment.

[0029] [Figure 2] Figure 2 shows the process according to one embodiment.

[0030] [Figure 3] Figure 3 shows selected experimental results from several embodiments.

[0031] [Figure 4] Figure 4 shows selected process parameters and experimental results from several embodiments.

[0032] [Figure 5] Figure 5 shows selected process parameters and experimental results from several embodiments. [Modes for carrying out the invention]

[0033] This disclosure is not limited to the specific systems, apparatus, and methods described, and these may change. Furthermore, the terminology used in this description is intended solely to describe specific versions or embodiments and is not intended to limit the scope of the invention. In addition, any list of patent documents, such as U.S. patents, U.S. patent application publications, World Intellectual Property Organization publications, or foreign patent application publications, as described herein, means that such documents are incorporated in their entirety by reference.

[0034] In this text, the singular forms "a," "an," and "the" include the plural form unless the context clearly indicates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art. Nothing in this specification should be construed as acknowledging that the embodiments described herein do not have prior rights to such disclosures by prior art. In this text, the term "including" means "including, but not limited to."

[0035] As used herein, the term "about" means a number plus or minus 10% of the number used. Therefore, "about 50" means "in the range of 45 to 55".

[0036] As used herein, the term “adsorbent” means any material exhibiting adsorption properties, absorption properties, or a combination of adsorption and absorption properties. Adsorption properties mean that atoms, ions, or molecules physically adhere to the surface of the material. Absorption properties mean that atoms, ions, or molecules enter and are held in the bulk phase of the material. Examples of adsorbents include activated carbon, reactivated carbon, natural and synthetic zeolites, silica, silica gel, alumina, zirconia, and diatomaceous earth. As used herein, “adsorbent” means a material whose components are substantially adsorbent and / or absorbent, and which has only the minimum amount of non-adsorbent and / or non-absorbent components (e.g., the minimum amount of binder necessary for activated carbon pellets to maintain their shape).

[0037] As used herein, the term “adsorbent” means any composition or composite material that contains an adsorbent in a blend, mixture, composite material, or compound with one or more additives that do not exhibit adsorbent properties. As an example, one embodiment of an adsorbent includes an activated carbon adsorbent mixed with a thermally conductive filler.

[0038] As used herein, the term “carbonaceous material” means a material containing carbon that is neither thermally nor chemically activated. Carbonaceous materials may be mechanically, thermally, or chemically treated and may even have weak adsorption properties, but they do not adsorb compounds in the same quantities as materials, such as activated carbon. Examples of carbonaceous materials include, but are not limited to, bituminous coal, subbituminous coal, lignite, anthracite, wood, wood chips, sawdust, peat, nut shells, pits, coconut shells, babassu palm, macadamia nuts, denden nuts, peach pits, cherry pits, olive pits, walnut shells, wood, lignin, polymers, nitrogen-containing polymers, resins, petroleum pitch, bagasse, rice husks, corn husks, wheat husks and husks, graphene, carbon nanotubes, or polymer fibers.

[0039] As used herein, the term “disinfection by-product” means a compound formed as a result of a chemical reaction between organic and inorganic substances present in water, and a compound used in a disinfection process, or a compound formed as a result of ultraviolet irradiation of organic and inorganic substances present in water. Examples of disinfection by-products include one or more of chlorine, chloramines, chloroform, trihalomethanes, haloacetic acids, and hydrogen peroxide. However, it should be noted that water that has not undergone a disinfection process may also contain compounds that are disinfection by-products.

[0040] As used herein, the term "macropore" refers to a pore in an adsorbent with a diameter greater than approximately 50 nm.

[0041] As used herein, the term "mesopore" refers to a pore in an adsorbent with a diameter of approximately 2 nm to 50 nm.

[0042] As used herein, the term "micropore" refers to pores in an adsorbent with a diameter of less than approximately 2 nm.

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

[0044] As used herein, the “apparent density” of an adsorbent or adsorbent material is obtained by the industry standard test ASTM D2854-09 (2019).

[0045] The adsorbents or adsorbents described herein are useful for removing chloroform and other similar volatile organic compounds (VOCs) from fluids, such as water. VOCs include 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-dichloropropylene, dinoseb, endrin, ethylbenzene, ethylene dibromide (EDB), bromochloroacetonitrile, dibromoacetonitrile, dichloroacetonitrile, and haloacetonitrile (HAN) including trichloroacetonitrile, 1,1-dichloro-2-propane This includes, but is not limited to, one or more of the following: non, and haloketones (HK) including 1,1,1-trichloro-2-propanone, heptachlor (H-34, Heptox), heptachlor epoxide, hexachlorobutadiene, hexachlorocyclopentadiene, lindyne, methoxychlor, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-TP (Sylvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, bromoform, bromodichloromethane, trihalomethanes including chlorodibromomethane, or xylene. VOCs relevant to the field of drinking water are publicly known in the industry and are described, for example, in NSF / ANSI 53-2019, which was designated in standard 6 May 2019 and is incorporated in its entirety by reference. In some cases, the removal of VOCs by adsorbents or adsorbents is measured by the removal of the individual VOC species themselves. In another embodiment, the removal of VOCs by adsorbents or adsorbents is measured by the removal of surrogate compounds. A surrogate is a compound that has a chemical composition similar to the sample of interest and is present in the sample before preparation and analysis. For example, chloroform is an example of a surrogate for the compounds in this paragraph.

[0046] The adsorbents or adsorbents described herein are also useful for removing other contaminants from water or other fluids, such as perfluoroalkyl and polyfluoroalkyl substances (PFAS). The PFAS compounds include one or more of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and compounds produced by the GENX process, such as 2,3,3,3,-tetrafluoro-2-(heptafluoropropoxy)propanoate and heptafluoropropyl 1,2,2,2-tetrafluoroethyl ether.

[0047] Adsorbents or adsorbents are also useful for removing a wide variety of emerging contaminants from water or other fluids. Such emerging contaminants include one or more of the following: meprobamate, phenytoin, atenolol, carbamazepine, tris(2-chloroethyl)phosphate (TCEP), tris(1-chloro-2-propyl)phosphate (TCPP), N,N-diethyl-meth-toluamide (DEET), metrachlor, trimethoprim, ibuprofen, naproxen, estrone, bisphenol A, linurone, or nonylphenol. Emerging contaminants relevant to the field of drinking water are publicly known in the industry and are described, for example, in NSF / ANSI 401-2017, which was specified in standard 12 January 2017 and is incorporated in its entirety by reference. In some cases, the removal of emerging compounds by adsorbents or adsorbents is measured by the removal of the individual emerging contaminant species itself.

[0048] Figure 1 shows one embodiment of the entire process 10 of the present disclosure. In Figure 1, a carbonaceous material is supplied 20, and then the carbonaceous material is activated 30 to form a precursor activated carbon. The precursor activated carbon is oxidized 40. After oxidation 40, the precursor activated carbon is doped 50, thereby imparting certain amounts of copper dopant and nitrogen dopant to the precursor activated carbon, thereby producing doped precursor activated carbon. Next, the doped precursor activated carbon is calcined 60 by heating at a specific temperature and in a specific atmosphere, and then cooled in an inert atmosphere 70 so as not to substantially alter the pore structure and not to substantially oxidize or activate the doped precursor activated carbon. Upon completion of calcination 60 and cooling 70, the adsorbent of the present disclosure is produced.

[0049] Processing of carbonaceous materials This disclosure provides one or more carbonaceous materials that are precursors to final adsorbents. Carbonaceous materials may be mechanically, heat-treated, or chemically treated, and may even have weak adsorption properties, but carbonaceous materials do not adsorb compounds in the same quantities as expected from materials such as activated carbon. Furthermore, although carbonaceous materials may be mechanically, heat-treated, or chemically treated, they are not treated in a way that activates carbon. Examples of carbonaceous materials include, but are not limited to, bituminous coal, subbituminous coal, lignite, anthracite, wood, wood chips, sawdust, peat, nut shells, pits, coconut shells, babassu palm, macadamia nuts, denden nuts, peach pits, cherry pits, olive pits, walnut shells, wood, lignin, polymers, nitrogen-containing polymers, resins, petroleum pitch, bagasse, rice husks, corn husks, wheat husks and husks, graphene, carbon nanotubes, and polymer fibers.

[0050] In some embodiments, the carbonaceous material is coconut shell. The carbonaceous material of coconut shell is particularly useful because, when activated to form activated carbon, it has excellent adsorption properties for chloroform and other organic compounds.

[0051] After the carbonaceous material is supplied, it is activated. The activation process is not limited; any suitable activation process can be used. These processes also depend on the type of carbonaceous material and the desired form of the final activated carbon, and the process includes one or more of the following: thermally decomposing the carbonaceous material to form charcoal; crushing the charcoal; mixing a binder with pulverized charcoal; briquetting the pulverized charcoal and binder; crushing the briquettes; adjusting the size of the crushed briquettes; and burning the adjusted-size briquettes or the briquettes themselves to carbonize, harden, or remove the binder. However, in all cases, the carbonaceous material in the form of calcined briquettes or adjusted-size particles is activated thermally, chemically, or thermally and chemically. Thermal activation is carried out by heating the calcined briquettes or adjusted-size particles in the presence of one or more of water, oxygen, and carbon dioxide. Chemical activation is carried out by impregnating the calcined briquettes or adjusted-size particles in the presence of a strong acid, a strong base, or a salt. It should be noted that whether each of the above steps is included in the process may vary depending on the carbonaceous material provided. For example, if the carbonaceous material is coconut, the process does not include "re-aggregation" but involves mixing the binder with pulverized coal, compressing the pulverized coal and binder, crushing the compressed body, and adjusting the size of the crushed compressed body.

[0052] As a result of processing carbonaceous materials, activated carbon is formed. As described herein, this activated carbon is referred to as “precursor activated carbon” because later disclosures describe additional steps applied to precursor activated carbon to further improve its performance. The performance of precursor activated carbon depends on several factors, including the type and amount of one or more carbonaceous materials included, the type of activation, including chemical or thermal activation, and the level of activation imparted to the carbonaceous materials to form precursor activated carbon. The performance of precursor activated carbon is also affected by other processing steps, such as grinding and sizing of the re-aggregated carbonaceous material particles, the level of residual binder, and the final size of the precursor activated carbon.

[0053] In all embodiments, the precursor activated carbon is not individually treated or oxidized beyond the steps outlined above. Therefore, the adsorption capacity of the precursor activated carbon itself is maintained and is not particularly dependent on the catalytic effect, resulting in a considerably large adsorption capacity for various disinfection by-products or other contaminant species. In some embodiments, the precursor activated carbon retains its ability to adsorb substantially all organic compounds of the species such as chloroform due to the internal pore structure of the precursor activated carbon.

[0054] Oxidation of precursor activated carbon This disclosure intends to describe the optional oxidation of precursor activated carbon. In some embodiments, the precursor activated carbon is oxidized after activation. Oxidation of precursor activated carbon means that the precursor activated carbon is exposed to oxygen molecules at a temperature sufficient to impart oxygen species or complexes to the surface of the activated carbon. The oxidation does not intend to substantially modify the pore structure of the precursor activated carbon.

[0055] For example, in some embodiments, oxidation is carried out by 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 may be in a range consisting of 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 the disclosed endpoints, or any combination of the above ranges or values ​​within those ranges. In different embodiments, the oxygen-containing environment is one or more of the following: air, oxygen gas (O2), oxygen plasma, hydrogen peroxide (H2O2), ozone (O3), nitrous oxide (N2O), vapor (i.e., dissociated O2), or carbon dioxide (CO2).

[0056] In some embodiments, the oxygen-containing environment is dry and free of moisture, or substantially free of measurable moisture. The choice of oxidation temperature and oxidizing agent and oxidation process does not substantially alter the pore structure of the precursor activated carbon. Therefore, if a more oxidative oxygen-containing environment is selected, the temperature must be lowered to reduce the likelihood of further activation. Alternatively, if a higher temperature is selected, a less oxidative oxygen-containing environment must be selected to reduce the likelihood of further activation.

[0057] Oxidation can also be achieved electrochemically. It should be noted that carbon oxidizes slowly at room temperature in the presence of air, with or without moisture, and this oxidation, though slow, is sufficient to eventually produce an oxidized carbon precursor. Alternatively, carbon can be oxidized in a non-thermal process using at least one of the following: nitric acid, potassium peroxymonosulfate, potassium persulfate, ammonium persulfate, sodium persulfate, hydrogen peroxide, peracetic acid, acetic acid, calcium hypochlorite, sodium hypochlorite, hypochlorous acid, benzoyl peroxide, sodium percarbonate, sodium perborate, organic peroxides, organic hydroperoxides, bleaching compounds, peroxide-based bleaches, chlorine-based bleaches, mixtures of hydrogen peroxide and urea, mixtures of peracetic acid and urea, and one or more combinations of the above. In some embodiments, the compounds used in non-thermal oxidation are in liquid or vapor phase and come into contact with the precursor activated carbon at a temperature below about 100°C.

[0058] Cu-N doping After the precursor activated carbon is prepared and oxidized as necessary, it is further treated by doping with a copper-nitrogen (Cu-N) compound. Doping with Cu-N imparts a Cu-N complex to the surface of the precursor activated carbon, thereby catalyzing disinfection byproducts. In the doping process, the copper compound source is copper sulfate pentahydrate, CuSO4·5H2O, or copper(II) carbonate hydroxide, Cu2CO3(OH)2. The nitrogen source is one or more of urea, CO(NH2)2, aqueous ammonium hydroxide, NH4OH (nominal 28 wt% aqueous solution), or ammonium carbonate, (NH4)2CO3. In some embodiments, the nitrogen source is supplied as part of the aqueous solution.

[0059] The doping process is not limited. In some embodiments, doping is carried out in a single step. In the single step process, the precursor activated carbon is treated by contacting it with a single solution containing both copper and nitrogen compounds. The copper compounds include copper(II) sulfate pentahydrate, CuSO4.5H2O, copper(II) carbonate hydroxide, Cu2CO3(OH)2, 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) nitrate sesquihydrate, Cu(NO3)2·1.5H2O, copper(II) nitrate di.pentahydrate, Cu(NO3)2·2.5H2O, copper(II) nitrate trihydrate, Cu(NO3)2·3H2O , copper(II) nitrate hexahydrate, Cu(NO3)2·6H2O, copper(II) acetate, Cu(CH3COO)2, copper(II) acetate monohydrate, Cu(CH3COO)2·H2O, copper(II) formate tetrahydrate, C2H 10 CuO8, copper hexamine complex, Cu(NH3)6 +2 、 The present invention includes, but is not limited to, those compounds, mixtures thereof, or combinations thereof. For example, in one embodiment, doping is carried out in one step by contacting the precursor activated carbon with an aqueous solution containing copper sulfate pentahydrate, CuSO4·5H2O, and urea, CO(NH2)2. In another embodiment, doping is carried out in one step by contacting the precursor activated carbon with an aqueous solution containing copper(II) carbonate hydroxide, Cu2CO3(OH)2, and one or more nitrogen sources selected from urea, CO(NH2)2, aqueous ammonium hydroxide, NH4OH (nominal 28 wt% aqueous solution), or ammonium carbonate, (NH4)2CO3. Other nitrogen-containing precursors having an oxidation state of -3, such as dicyandiamide, may be used.

[0060] In a one-step process of doping precursor activated carbon, the amounts of copper and nitrogen compounds 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 nitrogen in the solution, changing the length of time the solution is in contact with the precursor activated carbon, or changing the temperature of the solution.

[0061] After doping is achieved in a one-step process solution, the precursor activated carbon is dried to remove water or other solvents, thereby leaving the copper and nitrogen compounds on the precursor activated carbon. The drying process is not limited and is carried out by drying in air at 100°C to 150°C for up to 2 hours.

[0062] After a one-step process, the resulting doped and dried precursor activated carbon contains varying amounts of copper and nitrogen. For example, when measured on a dry carbon basis, the amount of copper added is approximately 0.1% by weight, 0.2% by weight, 0.3% by weight, 0.4% by weight, 0.5% by weight, 0.6% by weight, 0.7% by weight, 0.8% by weight, 0.9% by weight, 1.0% by weight, 1.1% by weight, 1.2% by weight, 1.3% by weight, 1.4% by weight, 1.5% by weight, 1.6% by weight, 1.7% by weight, 1.8% by weight, 1.9% by weight, 2.0% by weight, or any range including one or more of the above values ​​as endpoints. When measured on a dry carbon basis, the amount of nitrogen is approximately 1.5% by weight, 2.0% by weight, 2.2% by weight, 2.5% by weight, 3.0% by weight, 3.5% by weight, 4.0% by weight, 4.5% by weight, 5.0% by weight, 5.5% by weight, 6.0% by weight, 6.5% by weight, 7.0% by weight, 7.5% by weight, 8.0% by weight, 8.3% by weight, 8.5% by weight, and 9% by weight. 0.0% by weight, approximately 9.3% by weight, approximately 9.5% by weight, approximately 10.0% by weight, approximately 10.3% by weight, approximately 10.5% by weight, approximately 11.0% by weight, approximately 11.3% by weight, approximately 11.5% by weight, approximately 12.0% by weight, approximately 12.3% by weight, approximately 12.5% ​​by weight, approximately 12.0% by weight, 13.0%, or any range that includes one or more of the above values ​​as endpoints.

[0063] Figure 2 shows one embodiment of a one-step doping process 50. In the doping process 50, indicated by box 51, the precursor activated carbon is brought into contact with an aqueous solution containing a copper source and a nitrogen source. Next, the contacted precursor activated carbon is dried 52. After drying, the doped precursor activated carbon is ready for calcination.

[0064] Heat treatment / calcination After the completion of the one-step Cu-N doping process, the doped precursor activated carbon is ready for a heat treatment also known as calcination. During calcination, the doped precursor activated carbon is heated in the presence of a specific atmosphere, bringing about further changes to the doped precursor activated carbon.

[0065] The calcination temperature of the doped precursor activated carbon is not limited. In some embodiments, calcination is performed at temperatures of approximately 400°C, approximately 450°C, approximately 500°C, approximately 550°C, approximately 600°C, approximately 650°C, approximately 700°C, approximately 750°C, approximately 800°C, approximately 850°C, approximately 900°C, approximately 950°C, approximately 1000°C, approximately 1050°C, or any range including one or more of the above values ​​as endpoints.

[0066] A calcination atmosphere is an atmosphere that, at a specific temperature, does not cause any substantial oxidation or activation of the doped precursor activated carbon, so as not to alter the pore structure of the doped precursor activated carbon. Therefore, in many embodiments, the atmosphere contains neither oxygen, carbon dioxide, nor water, or contains such small amounts of oxygen, carbon dioxide, or water that neither oxidation nor activation occurs. Examples of atmospheres for calcination include nitrogen gas (N2), helium, neon, argon, krypton, xenon, and one or more of these in combination. Once calcination is complete, the resulting product is called an adsorbent.

[0067] In some embodiments, the adsorbent is granular activated carbon (GAC), defined as activated carbon particles that are small enough to remain on a 50-mesh sieve (holes approximately 0.300 mm). In another embodiment, the adsorbent is powdered activated carbon (PAC), defined as particles that pass through an 80-mesh sieve (holes approximately 0.180 mm). While these particle size ranges are mentioned for activated carbon adsorbents, it is also intended that any disclosed adsorbent may be measured by the 50-mesh and 80-mesh sieve sizes described above. In yet another embodiment, the adsorbent is pelletized activated carbon.

[0068] Performance measurement / adsorption characteristics evaluation The performance of the adsorbents of this disclosure is measured by various methods, including the “chloramine decomposition value” (CDN) as defined below. The chloramine decomposition value quantifies the amount of chloramine that can be removed from a fluid by the adsorbents of this disclosure. The measurement of CDN is known in the art, for example, in U.S. Patent No. 10,702,853, granted on July 7, 2020, entitled “CHLORAMINE AND CHLORINE REMOVAL MATER AND HOD FOR MAKING THE SAME,” which is incorporated herein by reference in its entirety.

[0069] CDN is the absolute value of the first-order linear kinetic fitting multiplied by 1000, applied to the natural logarithm of the chloramine concentration in water over time, representing the decrease in the initial chloramine concentration over 150 minutes. When ammonia is in equilibrium with chlorine in solution, the form of chloramine is pH-dependent. The chloramine solution contained ammonium chloride, and sodium hypochlorite and deionized water were mixed to obtain a 1 L solution of 300 ppm chloramine at pH 9.0. At pH 9.0, the chloramine species present in equilibrium is the monochloramine form, which is the most difficult to decompose. The solution was buffered using sodium carbonate to maintain the pH of the solution during evaluation. The chlorine solution contained sodium hypochlorite and deionized water to obtain a 1 L solution of 300 ppm chlorine. One liter of each 300 ppm solution was added to an Erlenmeyer flask placed in a water bath controlled at 20°C. For each sample analysis, a constant volume of 2.0 mL of activated carbon (size-adjusted to 80 × 325 mesh) was added to 1 L of stirred chloramine or chlorine solution. The volume of carbon used was determined from the apparent density of 80 × 325 carbon, measured by ASTM method D-2854. The total chlorine concentration in the solution was measured at various time points over 150 minutes by taking aliquots and then analyzing the total chlorine using standard HACH colorimetric EPA-approved method 10070.

[0070] After the adsorbents are experimentally analyzed, the concentration-versus-time data for each adsorbent sample are replotted as the natural logarithm of total chlorine concentration versus time, and the data are linearized according to first-order kinetics. Linear fitting is then applied to the data, and the gradient of the linear fitting is determined. Since the initial concentration of total chlorine decreases over 150 minutes, the gradient is always negative. As a result, the absolute value of the gradient multiplied by 1000 is used to quantify the rate of chloramine and chlorine decomposition (removal). A larger absolute gradient indicates a greater effectiveness of the adsorbent in removing chlorine and chloramine. In these measurements, the gradient resulting from the linear fitting of the first-order kinetic experimental data (multiplied by 1000, as before) is called the "chloramine decomposition value" or CDN. In the case of chlorine decomposition, this rate is called the "chlorine decomposition value" of Cl-DN. These values ​​quantify the amount of chloramine and / or chlorine that can be removed from water by the adsorbents or adsorbents of this disclosure.

[0071] In addition to chloramines, this disclosure is also effective for removing chlorine from fluids, such as aqueous flows. The ability of calcined activated carbon to remove chlorine was evaluated as described above, but the test solution was prepared without the addition of ammonium chloride, and therefore the solution contained 300 ppm of chlorine. The particle size of the adsorbent for chlorine analysis was approximately 325 mesh for 95% of cases. However, the analysis of chlorine concentration versus time data and the corresponding first-order kinetic gradient remained the same, and the gradient of the linear fitting of this data is called the "chlorine decomposition value" or Cl-DN.

[0072] In addition, the "peroxide decomposition value," also known as the "peroxide value," is measured. The peroxide value is a volumetric test, meaning that the performance is measured and normalized to a specific volume of the adsorbent. The peroxide value test is well known in the art and is described in U.S. Patent No. 5,470,748, which is incorporated herein by reference in its entirety.

[0073] During the peroxide value test, the adsorbent is first ground into a fine mesh fraction, at least 90% by weight of the adsorbent, and at least 95% by weight in certain tests, passing through a 325-mesh US Standard Series sieve (aperture size 44 μm). A specific amount of the ground adsorbent is placed in a vacuum flask (dewar), and 100 mL of deionized water is added to the vacuum flask. The addition of the deionized water is done so that any ground adsorbent adhering to the sides of the vacuum flask is carried into the water body at the bottom of the vacuum flask. Next, a 50 mL aliquot of the buffer solution is added to the vacuum flask. The aqueous buffer solution is 0.5 moles for K2HPO4 and 0.5 moles for KH2PO4. After adding the aqueous buffer solution, a magnetic stirring rod is added to the vacuum flask, and stirring is started by applying power. The stirring speed was increased until a vortex with a depth of more than approximately 0.5 inches (1.27 cm) was formed in the mixture and the optimal stirring rod speed was achieved. The optimal stirring rod speed is selected so that further increases in the stirring rod speed do not significantly affect the peroxide decomposition time.

[0074] As explained in the previous paragraph, during the peroxide value test, a specific amount of adsorbent is added to buffered hydrogen peroxide solution. Since this test is a volumetric test, the specific amount of adsorbent added to the buffered hydrogen peroxide solution is based on half (1 / 2) of the apparent density of the adsorbent. In particular, the apparent density of the adsorbent is g / cm³ 3 When reported, the gram mass of the adsorbent added to the solution is equal to half (1 / 2) of the measured apparent density of the adsorbent. In a buffer solution, the catalytic properties of the adsorbent catalyze the peroxide, thereby causing its decomposition (i.e., hydrogen peroxide decomposes into water and oxygen gas).

[0075] Hydrogen peroxide catalysts are exothermic. Therefore, the decomposition rate by the adsorbent can be estimated over time by measuring the temperature of the buffer solution. As used herein, "peroxide value" is the time in minutes required for the buffer solution containing the adsorbent sample to reach 75% of the highest recorded temperature. A shorter time for the peroxide value, and therefore a smaller value, indicates higher catalytic activity and therefore a more effective adsorbent. In some embodiments, the peroxide decomposition value measured in minutes is about 2.5, about 3.0, about 3.5, about 4.0, about 4.5, about 5.0, about 5.5, about 6.0, about 6.5, about 7.0, or any range formed from two or more of the above values ​​as endpoints of the range. In some embodiments, the peroxide decomposition 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 from two or more of the above values ​​as endpoints of the range.

[0076] The peroxide value is related to CDN and C1-DN, and there is some correlation between them, as CDN and C1-DN are measures of the catalytic activity of the adsorbent, respectively. However, the correlation is not always precise because each represents a different aspect of the catalytic activity of the adsorbent. Furthermore, catalytic activity is only useful for the compound being catalyzed, while other compounds must be adsorbed to be effectively removed from the fluid flow. Therefore, a superior adsorbent will have excellent performance in one or more of the following tests: CDN, C1-DN, peroxide value, and adsorption test, and thus can effectively remove a wide range of compounds from the fluid flow.

[0077] Fluid processing Another embodiment relates to a method for purifying a fluid, such as water, by using the chlorine and chloramine decomposing adsorbents described above. In one embodiment, the fluid is treated by flowing the fluid over an adsorbent bed, introducing the fluid onto a filter equipped with the adsorbent, or placing the adsorbent in a container for holding the fluid. In some embodiments, the above steps are combined in parallel or subsequently in succession. In some embodiments, the fluid is water. In yet another embodiment, the fluid is water for consumption by humans, plants, animals, or marine organisms. In some embodiments, the fluid is liquid.

[0078] In other embodiments, the method for purifying the fluid includes additional steps. For example, in some embodiments, the purification method includes filtering the fluid using, for example, a screen or sand filter, before, after, or both before and after contacting it with an adsorbent to remove particulate matter. In other embodiments, the method includes disinfecting the water to remove biological contaminants, such as bacteria or other microorganisms, and in some embodiments, the method includes adding a disinfectant to the fluid or irradiating the fluid with ultraviolet light. In yet another embodiment, the method includes purifying the fluid, adjusting the pH of the fluid, and so on, and combinations thereof. In each of the above embodiments, the fluid may be water. [Examples]

[0079] The following experimental examples are intended to better illustrate specific embodiments and are not intended to limit the disclosure.

[0080] One-step process example Coconut shell carbonaceous material is supplied, processed, and activated. The resulting coconut shell activated carbon is available from Calgon Carbon Corporation under the product name OLC and is called precursor activated carbon. Coconut shell activated carbon is granular activated carbon and is tested in sizes 12×30 and 12×40. As used herein, activated carbon specified by numerical values ​​such as 12×40 is specified as all particles that pass through a 12 US mesh size (1.7 mm opening) screen, but they are retained by a 30 US mesh (0.6 mm opening) screen. Thus, using the 12×40 example again, the activated carbon will have a particle size of approximately about 0.6 mm to about 1.7 mm. Precursor activated carbon is oxidized in some tests but not in others. After supplying the precursor activated carbon and performing the oxidation process as needed, the precursor activated carbon is ready to be doped with Cu and N. As used herein and throughout the claims, “precursor activated carbon” refers to either oxidized or unoxidized activated carbon, depending on the context.

[0081] CuSO4·5H2O / urea doping process During Cu and N doping, a one-step doping process is carried out. The one-step doping process dops oxidized or unoxidized precursor activated carbon with copper and nitrogen. During the one-step doping process, aqueous solutions containing both copper sulfate pentahydrate and urea come into contact with oxidized or unoxidized precursor activated carbon to yield 0.25–2.0 wt% Cu and 9.5 wt% N on the carbon (based on dry precursor activated carbon).

[0082] The aqueous solution is brought into contact with the precursor activated carbon at ambient temperature for up to 30 minutes. After the aqueous solution has come into contact with the precursor activated carbon, the precursor activated carbon is dried at approximately 100°C to approximately 150°C for up to 2 hours, thereby producing doped precursor activated carbon. Examples are shown in Table 1 below.

[0083] Next, the dried and doped precursor activated carbon is calcined. During calcination, the doped precursor activated carbon is heated to approximately 950°C for about 1 hour in a pure N2 atmosphere. The resulting copper and nitrogen-treated activated carbon exhibits excellent adsorption performance when in contact with chloramine.

[0084] Experimental results The above CDN and peroxide decomposition values ​​were measured for representative groups of samples and controls, as shown below.

[0085] In each case shown in Table 1, the Cu-N combination performed better than the control. Furthermore, pre-oxidation of activated carbon in air (Ox OLC) improved the CDN and shortened the peroxide time compared to the unoxidized sample (OLC). While we do not wish to be bound by any theory, it is thought that selecting coconut as the carbonaceous material for forming precursor activated carbon may also significantly improve the performance of chloroform and VOCs. However, the performance of chloroform and VOCs has not been evaluated to date. [Table 1]

[0086] Another experiment was conducted in which the amount of Cu added to the carbon (before calcination) was fixed at either 0.5 or 1.0 wt% (see Figure 3). While increasing the amount of urea added to 4.3–15.0 wt% did not dramatically increase the CDN, a tendency for increased CDN was observed when more copper was added to the precursor activated carbon. Complementary peroxide data for Figure 3 were not generated, but it is possible that smaller (i.e., shorter time) peroxide values ​​could be obtained as the amount of urea added to the activated carbon increased.

[0087] Copper(II) carbonate hydroxide / ammonium hydroxide / ammonium carbonate doping process During Cu and N doping, a one-step doping process is performed. This process involves doping oxidized or unoxidized precursor activated carbon with copper and nitrogen from a copper source other than copper sulfate. In these tests, the nitrogen source is not limited and may come from multiple sources.

[0088] This method avoids the use of copper sulfate, which may be beneficial in terms of emission control and corrosion reduction, by avoiding the formation of acidic SO3.

[0089] Here, the copper source is copper(II) carbonate hydroxide, Cu2CO3(OH)2. The copper concentration is based on the weight percentage (on a dry carbon basis) of Cu added to the precursor activated carbon before any heat treatment.

[0090] The nitrogen source may be any or all of the following: ammonium hydroxide (NH4OH (e.g., aqueous ammonia, 28 wt%)), ammonium carbonate, (NH4)2CO3, urea, and CO(NH2)2. The total nitrogen concentration is based on the weight % of N (on a dry carbon basis) added to any precursor activated carbon before heat treatment. As described above, nitrogen is provided by combinations of these nitrogen sources in various molar percentages. In addition to the weight % of nitrogen (on a dry carbon basis) added to the activated carbon precursor, Figures 4-5 also show the percentage of elemental nitrogen added to carbon (as before drying and calcination) from each nitrogen source, reported as N mol%. Other nitrogen-containing precursors with an oxidation state of -3, such as dicyandiamide, can be used.

[0091] The doping process involves using a doping solution. Mixing 1 part of a 28 wt% ammonium hydroxide aqueous solution with 1 part of water (by volume), Add the desired amount of ammonium carbonate to the solution, Add the desired amount of urea to the solution, Add the desired amount of copper(II) carbonate hydroxide to the solution, This is done by gently heating the solution until all the solids are dissolved (usually between 25 and 100°C) and by first mixing the solids.

[0092] Next, the doping aqueous solution is brought into contact with the precursor activated carbon at ambient temperature for up to 30 minutes. After the aqueous solution has come into contact with the precursor activated carbon, the precursor activated carbon is dried at approximately 100°C to 150°C for up to 2 hours, thereby producing doped precursor activated carbon.

[0093] Next, the dried and doped precursor activated carbon is calcined. During calcination, the doped precursor activated carbon is heated to approximately 950°C for about 1 hour in a pure N2 atmosphere. The resulting copper and nitrogen-treated activated carbon exhibits excellent adsorption performance when in contact with chloramine, as shown in Figure 4.

[0094] Experimental results As shown in Figure 4, the CDN value reaches a high value of 12.9. The copper(II) carbonate hydroxide-nitrogen doping method yields a similar CDN value to the copper sulfate-urea method (see Table 1), but has the added advantage of avoiding the elimination and other problems associated with copper sulfate. Therefore, in some embodiments and situations, this is an alternative route for achieving good chloramine performance.

[0095] The performance of the peroxide has not been measured.

[0096] While various embodiments present specific activated carbons, the process described herein should be suitable for a variety of activated carbons. In particular, the combination of copper and nitrogen sources may also be effective for coal-based precursor activated carbons, such as F400 available from Calgon Carbon Corporation. In the disclosed embodiments, as shown in Figure 5, F400 precursor activated carbon oxidized and treated according to this disclosure exhibited excellent performance, reaching a high CDN value of 50.0. Furthermore, catalytic coal-based precursor activated carbons, such as CENTAUR available from Calgon Carbon Corporation and prepared as described in U.S. Patent No. 5,504,050, are expected to yield excellent performance whether oxidized or not before the doping process. U.S. Patent No. 5,504,050 is incorporated herein by reference in its entirety.

[0097] Based on the copper compounds used in these embodiments, copper in any oxidized state is expected to be effective in obtaining activated carbon with enhanced catalytic properties. Similarly, another nitrogen source, such as dicyandiamide (DCD), but not limited to this one, can be used as nitrogen in place of urea and / or ammonia or compounds containing nitrogen in an oxidized state of -3.

[0098] The CuSO4 / urea doping method for oxidized OLC is facilitated by high-temperature calcination at approximately 950°C. Lower temperatures reduce catalytic activity. For example, increasing the calcination temperature to approximately 600°C to 1000°C results in improved performance as measured by CDN.

[0099] The detailed description above refers to the accompanying drawings, which form part of this specification. In the drawings, unless otherwise indicated in the context, similar symbols typically identify similar components. The exemplary embodiments described in the descriptions, drawings, and claims for carrying out the invention are not intended to limit the scope. Other embodiments may be used and other modifications may be made without departing from the spirit or scope of the subject matter presented herein. Generally, the aspects of this disclosure described herein and shown in the drawings may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are expressly intended herein.

[0100] This disclosure is not limited to the specific embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from the spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatus within the scope of this disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. This disclosure is limited only by the terminology of the appended claims and encompasses the entire scope of equivalents to which such claims are entitled. This disclosure is not limited to methods, reagents, compounds, compositions, or biological systems, which may vary. It should also be understood that the terminology used herein is intended to describe only specific embodiments and is not intended to limit them.

[0101] With regard to the use of substantially any plural and / or singular terms herein, those skilled in the art can translate from plural to singular and / or singular to plural where appropriate to the context and / or use. Various singular / plural arrangements may be explicitly listed herein for clarity.

[0102] It will be understood by those skilled in the art that the terms used herein, in particular in the appended claims (e.g., the body of the appended claims), are generally intended to be “open” terms (for example, the term “including” should be interpreted as “including, but not limited to,” the term “having” should be interpreted as “having at least,” and the term “includes” should be interpreted as “including, but not limited to,” etc.). Various compositions, methods, and devices are described in that they “include” various components or processes (interpreted as “including, but not limited to,” but compositions, methods, and devices can also “essentially” consist of, or “become,” various components and processes, and such technical terms should be interpreted as defining essentially closed member groups. It will further be understood by those skilled in the art that if a particular number of claims enumerations is intended, such intent is explicitly enumerated in the claims, and if no such enumeration is present, such intent does not exist.

[0103] For example, as an aid to understanding, the attached claims below may include the use of the introductory phrases “at least one” and “one or more” to introduce the enumeration of claims. However, the use of such phrases should not be interpreted as implying that the introduction of the enumeration of claims by the indefinite article “one (a)” or “one (an)” implies that any particular claim containing such introduced enumeration of claims is limited to embodiments containing only one such enumeration, even if the same claim contains the introductory phrases “one or more” or “at least one,” and indefinite articles such as “one (a)” or “one (an)” (for example, “one (a)” and / or “one (an)” should be interpreted as meaning “at least one” or “one or more”). The same applies to the use of specific articles used to introduce the enumeration of claims.

[0104] Furthermore, even if a particular number of claims enumerations introduced is explicitly listed, a person skilled in the art will recognize that such enumerations should be interpreted as meaning at least the number listed (e.g., without other modifiers, at least two enumerations, or two or more enumerations, e.g., a straightforward enumeration and "two enumerations"). Moreover, in these instances where conventions similar to "at least one of A, B, and C, etc." are used, such structures are generally intended in the sense that a person skilled in the art will understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Furthermore, in these instances where conventions similar to “at least one of A, B, or C” are used, such structures are generally intended to be understood by those skilled in the art (for example, “a system having at least one of A, B, or C” includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together). It will be further understood by those in the art that substantially any separate word and / or phrase presenting two or more alternative terms in the description, claims, or drawings should be understood to contemplate the possibility of including the terms, either of those terms, or both. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[0105] Furthermore, if any feature or aspect of the present disclosure is described in relation to the Markush group, a person skilled in the art will recognize that the present disclosure is also described in relation to any individual member or subgroup of a member of the Markush group.

[0106] As will be understood by those skilled in the art, for any and all purposes, including providing written descriptions, all scopes disclosed herein also encompass any and all possible subscopes and combinations thereof. The enumerated scopes can be readily recognized as fully describing and enabling the same scopes to be divided into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-restrictive example, each scope discussed herein can be readily divided into lower thirds, middle thirds, upper thirds, etc. Also, as will be understood by those skilled in the art, all language such as “up to” and “at least” includes the enumerated number and then refers to a scope that can be divided into subscopes as discussed above. Finally, as will be understood by those skilled in the art, a scope includes each individual member. Thus, for example, a group having 1 to 3 components refers to a group having 1, 2, or 3 components. Similarly, a group having 1 to 5 components refers to a group having 1, 2, 3, 4, or 5 components, etc.

[0107] The various other features and functions described above, or their alternatives, may be combined with many other different systems or applications. Various alternatives, modifications, variations, or improvements that are not currently anticipated or expected may subsequently be made by those skilled in the art, each of which is also intended to be encompassed by embodiments of this disclosure.

Claims

1. A method for manufacturing an adsorbent, wherein the method is The process of supplying carbonaceous material, A step of activating the carbonaceous material to form a precursor activated carbon, The process involves doping the precursor activated carbon by contacting it with a copper source and a nitrogen source, thereby forming doped precursor activated carbon. The aforementioned doped precursor activated carbon does not undergo any substantial oxidation or activation, N ２ A method comprising the step of calcining the doped precursor activated carbon in a calcination atmosphere at a temperature of approximately 600°C to approximately 1000°C, thereby forming an adsorbent.

2. The copper source is copper sulfate pentahydrate, CuSO ４ ·5H ２ O, or copper (II) carbonate hydroxide, Cu ２ CO ３ (OH) ２ 0 selected from, the nitrogen source is urea, CO(NH ２ ) ２ , ammonium carbonate, (NH ４ ) ２ CO ３ , or an aqueous ammonium hydroxide solution, NH ４ OH (nominal 28 wt% aqueous solution), one or more of which, the method according to claim 1.

3. The copper source is copper sulfate pentahydrate, CuSO4. ４ ・5H ２ Selected from O, the nitrogen source is urea, CO(NH ２ ) ２ The method according to claim 2.

4. The copper source is copper(II) carbonate hydroxide, Cu ２ CO ３ (OH) ２ The nitrogen source is urea, CO(NH ２ ) ２ , ammonium carbonate, (NH ４ ) ２ CO ３ , or aqueous solution of ammonium hydroxide, NH ４ The method according to claim 2, wherein one or more of OH (nominal 28% by weight aqueous solution).

5. The method according to claim 1, wherein doping the precursor activated carbon is a one-step process, the one-step process comprising a single step of contacting the precursor activated carbon with both a copper source and a nitrogen source.

6. The method according to claim 1, wherein contacting the precursor activated carbon with the copper source and the nitrogen source is carried out using a single aqueous solution containing both the copper source and the nitrogen source.

7. The method according to claim 6, wherein the precursor activated carbon is dried after being in contact with the single aqueous solution containing the copper source and the nitrogen source.

8. Temporary burning, N ２ The method according to claim 1, which is carried out in an atmosphere at a temperature of approximately 700°C to approximately 1000°C.

9. Temporary burning, N ２ The method according to claim 1, which is carried out in an atmosphere at a temperature of approximately 850°C to approximately 1000°C.

10. The method according to claim 1, further comprising oxidizing the precursor activated carbon before doping.

11. A method for removing chlorine, chloramine, or both chlorine and chloramine from a fluid, wherein the method is: A step of supplying an adsorbent comprising activated carbon doped with copper and nitrogen, wherein the adsorbent is formed from a carbonaceous material that is activated to form a precursor activated carbon, the adsorbent contains about 2% to about 15% by weight of nitrogen as measured on a dry precursor activated carbon basis, and about 0.25% to about 2% by weight of copper as measured on a dry precursor activated carbon basis, and the adsorbent has a chloramine decomposition value (CDN) of at least about 6, the supply step, A method comprising the step of bringing the adsorbent into contact with the fluid.

12. The method according to claim 11, wherein the fluid is liquid water.

13. The method according to claim 12, further comprising the step of disinfecting the water before bringing the adsorbent into contact with the fluid.

14. The method according to claim 11, wherein the adsorbent has a chloramine decomposition value (CDN) of about 6 to about 60.

15. The aforementioned adsorbent material is Based on measurements using dried precursor activated carbon as a standard, it contains approximately 2% to 15% by weight of nitrogen, It contains approximately 0.25% to 2% by weight of copper, as measured by the dry precursor activated carbon standard. The method according to claim 1, wherein the adsorbent has at least about 6 chloramine decomposition values ​​(CDN).

16. The method according to claim 15, wherein the number of CDNs is approximately 6 to approximately 60.

17. The method according to claim 15, wherein the adsorbent is made of a carbonaceous material formed from one or more of coal, wood, and coconut.

18. The method according to claim 17, wherein at least a portion of the carbonaceous material is formed from coconut.

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