Modified activated carbon as well as preparation method and application thereof

Abstract

The invention relates to modified activated carbon as well as a preparation method and application thereof, and belongs to the technical field of environmental governance. The method comprises the following steps: (1) carrying out dipping treatment on activated carbon in alkali liquor to obtain intermediate activated carbon; and (2) mixing and stirring the intermediate activated carbon and the steeping liquor, and performing drying treatment and calcining treatment to obtain the activated carbon, the impregnation liquid contains a copper source and a zinc source. According to the method, firstly, the activated carbon is subjected to alkaline leaching, hydroxyl sites on the activated carbon are increased, then zinc oxide and metal copper are loaded on the surface of the activated carbon subjected to alkaline leaching, the adsorption capacity of the modified activated carbon to mercaptan and thioether is improved, and the treatment capacity of the modified activated carbon to the organic sulfur-containing malodorous gas is improved.

Description

Technical Field

[0001] This invention relates to a modified activated carbon, its preparation method, and its application, belonging to the field of environmental remediation technology. Background Technology

[0002] Organic sulfur gases, primarily composed of thiols and thioethers, constitute a significant category within odor pollution systems. Of the eight restricted odor pollutants stipulated in my country's "Odor Pollutant Emission Standard" (GB14554-1993), organic sulfur substances account for four. Due to their wide range of sources, high toxicity, and tendency to undergo chemical transformation, the development of control technologies for these gases has become a research hotspot in the field of environmental governance.

[0003] Organic sulfur odor gases such as dimethyl sulfide, methanethiol, and ethanethiol have similar strong reducing properties to hydrogen sulfide, and thiols also have a certain degree of acidity. Therefore, some technologies used to treat hydrogen sulfide can be applied to the treatment of organic sulfur odor gases. However, organic sulfur odor gases are essentially organic compounds, and their purification process requires specific methods tailored to their unique characteristics.

[0004] Currently, commonly used treatment technologies can be mainly divided into several categories: physical methods include dilution, masking, and cryogenic condensation; chemical methods include combustion, chemical absorption, chemical adsorption, and chemical oxidation; in addition, there are biological methods and various new treatment technologies.

[0005] Adsorption is the most commonly used method for treating medium- and low-concentration odorous waste gases. The core principle of adsorption is to utilize the physical or chemical action of the adsorbent to fix pollutants in the odorous gas onto the adsorbent surface, achieving separation of the odorous substances from the air and ultimately purifying the gas. Currently, most commercially available adsorbents in industry are porous materials, such as activated carbon, molecular sieves, and silica gel. Activated carbon is a porous material with a large adsorption capacity, exhibiting excellent adsorption ability and selective adsorption performance.

[0006] Activated carbon has a wide range of sources and possesses a highly developed pore structure, ultra-large specific surface area, good thermal stability, and low production cost. These advantages make it a key research object in the desulfurization field at home and abroad for a long time, exhibiting performance that is difficult to replace by metal oxides and molecular sieves when used as an adsorption desulfurization agent.

[0007] However, when using activated carbon alone as a desulfurizing agent, it generally suffers from low sulfur capacity and narrow adaptability to different sulfides. In actual use, frequent replacement of the adsorbent is required, increasing operating costs and maintenance workload.

[0008] Currently, industrial activated carbon struggles to simultaneously meet the demands of fine desulfurization in terms of both pore structure optimization and surface functional group regulation. Therefore, overcoming these limitations and developing activated carbon desulfurizers with high sulfur capacity and broad sulfide adaptability has become a core research direction in this field. Practice has shown that pore structure reconstruction and surface functional group modification of activated carbon are effective ways to improve its desulfurization performance. Specific modification methods mainly include three categories: pore structure adjustment, surface property regulation, and the preparation of metal composite activated carbon.

[0009] Based on this, some researchers or enterprises have carried out research on activated carbon modification processes. For example, Chinese patent (publication number CN119488951A) discloses a novel desulfurization catalyst and its preparation method and application. The catalyst uses activated carbon modified with potassium solution as a carrier and one or more of CH3COOCs, CH3COOK, Cs2CO3, and Rb2CO3 as active components. The mass ratio of active component to modified activated carbon is 3-5%. The preparation steps are as follows: (1) Modify activated carbon with a potassium solution of 15-20% concentration, soak the activated carbon in the potassium solution for 2-4 h, then wash it with deionized water until the pH value is weakly alkaline, and dry it for later use; (2) After the above modified activated carbon is vacuum dried at a certain temperature, it is impregnated with a certain amount of active component solution at 20-60℃ for 4-12 h; (3) The above impregnated activated carbon is vacuum dried and calcined under N2 protection to obtain the desulfurization catalyst.

[0010] Chinese patent (publication number CN119680542A) discloses a columnar activated carbon catalyst for removing methyl sulfide and its preparation method. The preparation method includes the following steps: taking columnar activated carbon as raw material; soaking it in hydrochloric acid, filtering it, drying it at 150 ℃, mixing the dried sample with water, hydrothermally reacting it at 80 ℃ for 180 min, filtering it, and drying it to obtain modified activated carbon; taking cuprous chloride and ammonia water, stirring and mixing them to prepare a diamminecuprous chloride solution; immersing the modified activated carbon in the diamminecuprous chloride solution, stirring it until the solution is completely absorbed by the activated carbon, letting it stand, drying it with hot air at 170 ℃, and adjusting the temperature to 140~160 ℃ when the activated carbon is in a boiling state to obtain calcined and dried impregnated activated carbon. Summary of the Invention

[0011] In view of the problems existing in the prior art, one of the objectives of the present invention is to provide a method for preparing modified activated carbon. The method first involves alkaline leaching of activated carbon to increase the hydroxyl sites on the activated carbon, and then loading zinc oxide and copper metal onto the surface of the alkaline-leached activated carbon, thereby improving the adsorption capacity of the modified activated carbon for thiols and sulfides and enhancing its ability to treat organic sulfur-containing odorous gases.

[0012] The second objective of this invention is to provide a modified activated carbon that has a large adsorption capacity for organic sulfur odor gases.

[0013] A third objective of this invention is to provide modified activated carbon for the adsorption of odorous organic sulfur gases. This modified activated carbon exhibits a large adsorption capacity for odorous organic sulfur gases, particularly for thiols and thioethers.

[0014] To achieve the above objectives, a first aspect of the present invention provides a method for preparing modified activated carbon, the method comprising:

[0015] (1) The activated carbon is impregnated in an alkaline solution to obtain intermediate activated carbon;

[0016] (2) The intermediate activated carbon is mixed and stirred with the impregnation solution, and then dried and calcined to obtain the final product;

[0017] The calcination temperature is 420~480℃;

[0018] The impregnation solution contains a copper source and a zinc source.

[0019] This invention first involves alkaline leaching of activated carbon to increase the number of hydroxyl sites on the activated carbon. Then, the alkaline-leached activated carbon is impregnated with an impregnation solution containing copper and zinc sources, followed by calcination. During calcination, zinc from the zinc source and copper from the copper source generate ZnO and CuO. Furthermore, CuO can react with C in the activated carbon to form Cu (in this invention, CuO can be reduced during the calcination process, but ZnO cannot). These generated ZnO, Cu, and any unreduced CuO are loaded onto the surface of the activated carbon. In addition to the physical adsorption of the activated carbon itself, the introduced metals and metal oxides serve as active reaction centers. Cu acts as a desulfurization center, while ZnO and any remaining CuO act as sulfur carriers, increasing the number of active site sites on the surfaces of ZnO and CuO particles to enhance reactivity and thus increase the treatment capacity for organic sulfur-containing odorous gases, especially for thiols and thioethers.

[0020] As a preferred embodiment, the activated carbon has a particle size of 2-5 mm, an iodine adsorption value ≥800 mg / g, and a specific surface area ≥800 m². 2 / g, bulk density is 350~450 g / L, moisture content ≤5%.

[0021] As a preferred embodiment, the molar ratio of zinc in the zinc source to copper in the copper source in the impregnation solution is 1:0.5~2. The inventors have found that when the ratio of zinc to copper is not in this preferred configuration, the adsorption effect on organic sulfur odorous gases is reduced.

[0022] As a preferred embodiment, the molar ratio of zinc in the zinc source to copper in the copper source in the impregnation solution is 1:1.

[0023] As a preferred embodiment, the volume ratio of the intermediate activated carbon to the impregnation solution is 1:0.8~1.2. Too much impregnation solution will prolong the drying time, while too little impregnation solution will result in uneven mixing.

[0024] As a preferred embodiment, the alkaline solution is a potassium hydroxide solution and / or a sodium hydroxide solution.

[0025] As a preferred embodiment, the alkaline solution is a 18-22 wt% potassium hydroxide solution and / or sodium hydroxide solution.

[0026] As a preferred embodiment, the method further includes, in step (1), washing the solid obtained by impregnation with deionized water until the pH value no longer changes, and then drying it at 100~110℃ to constant weight to obtain intermediate activated carbon.

[0027] As a preferred embodiment, the volume ratio of activated carbon to alkaline solution is 0.4~0.6:1.

[0028] As a preferred embodiment, the immersion treatment time is 20-30 hours.

[0029] As a preferred embodiment, the method for preparing the impregnation solution includes embodiment (a) or embodiment (b):

[0030] Solution (a): The zinc salt solution I and the copper salt solution I are mixed to obtain the solution.

[0031] Scheme (b): Zinc salt solution II is first mixed with surfactant I, and then mixed with alcohol solution I to obtain sol 1; wherein alcohol solution I contains diacid and / or polyacid;

[0032] Furthermore, copper salt solution II is mixed with surfactant II in a third mixing process, and then mixed with alcohol solution II in a fourth mixing process to obtain sol 2; wherein alcohol solution II contains diacid and / or polyacid;

[0033] The sol 1 and the sol 2 are mixed to obtain the final product.

[0034] As a preferred embodiment, in embodiment (a), the impregnation solution contains 0.07~0.08 mol / L of zinc acetate and 0.035~0.16 mol / L of copper acetate.

[0035] As a more preferred embodiment, in embodiment (a), the impregnation solution contains 0.07~0.08 mol / L of zinc acetate and 0.07~0.08 mol / L of copper acetate.

[0036] It should be noted that the present invention does not have special requirements on the concentration and amount of the zinc salt solution I and the copper salt solution I, as long as the zinc salt solution I and the copper salt solution I are mixed to meet the above preferred scheme.

[0037] As a preferred embodiment, in embodiment (b), surfactant I and surfactant II are each independently Tween 80 and / or polyethylene glycol.

[0038] As a preferred embodiment, in embodiment (b), the volume of surfactant I is 1.5 to 2.5% of the volume of zinc salt solution II, and the volume of surfactant II is 1.5 to 2.5% of the volume of copper salt solution II.

[0039] As a preferred embodiment, in embodiment (b), the zinc salt solution II is a 0.5~0.7 mol / L zinc acetate solution.

[0040] As a preferred embodiment, in embodiment (b), the copper salt solution II is a 0.5~0.7 mol / L copper acetate solution.

[0041] As a preferred embodiment, the alcohol solution I contains oxalic acid, and the concentration of oxalic acid in the alcohol solution I is 0.5~0.7 mol / L.

[0042] As a preferred embodiment, the alcohol solution II contains oxalic acid, and the concentration of oxalic acid in the alcohol solution II is 0.5~0.7 mol / L.

[0043] As a preferred embodiment, the ratio of the total molar amount of the dicarboxylic acid and polycarboxylic acid in the alcohol solution I to the molar amount of zinc in the zinc salt solution II is 3.5~2.5:1;

[0044] The ratio of the total molar amount of dicarboxylic acid and polycarboxylic acid in the alcohol solution II to the molar amount of copper in the copper salt solution II is 3.5~2.5:1.

[0045] As a more preferred embodiment, the method of embodiment (b) further includes: after first mixing zinc salt solution II with surfactant I, heating the resulting mixed solution and alcohol solution I to 65~75°C respectively, and then second mixing the heated mixed solution and heated alcohol solution I and letting it stand for 50~80 min to obtain sol 1;

[0046] After the copper salt solution II and surfactant II are mixed for the third time, the resulting mixed solution and alcohol solution II are heated to 65~75℃ respectively. Then, the heated mixed solution and the heated alcohol solution II are mixed for the fourth time and allowed to stand for 50~80 minutes to obtain sol 2.

[0047] The inventors discovered that heating the solution before mixing allows for faster gel formation, thus enhancing the adsorption capacity of the prepared modified activated carbon for organic sulfur-containing odorous gases.

[0048] It should be noted that the "heating the obtained mixed solution and alcohol solution I to 65~75°C respectively, and then mixing the heated mixed solution and the heated alcohol solution I a second time" mentioned in this invention means that the mixed solution and alcohol solution II after the first mixing are heated and then mixed, but no heating treatment is required for the second mixing, and the temperature of the second mixing is the natural temperature.

[0049] The "heating the obtained mixed solution and alcohol solution II to 65~75°C respectively, and then mixing the heated mixed solution and the heated alcohol solution II for the fourth time" mentioned in this invention means that the mixed solution and alcohol solution II after the third mixing are heated and then mixed, but no heating treatment is required for the fourth mixing, and the temperature of the fourth mixing is the natural temperature.

[0050] As a preferred embodiment, the impregnation solution is prepared using embodiment (b). The sol-gel method increases the specific surface area of ​​activated carbon, preparing the modified activated carbon into suitable solid particles and crystal sizes. Simultaneously, by using the sol-gel method to load Cu and ZnO onto the activated carbon, the reaction space can be increased, thereby enhancing the adsorption capacity of activated carbon for thiols and thioethers.

[0051] As a preferred embodiment, in step (2), the drying temperature is 100~110℃. The present invention does not have special requirements regarding the drying time; it is sufficient to dry the solid obtained from mixing and stirring to a constant weight.

[0052] As a preferred embodiment, the calcination treatment is carried out under a protective atmosphere for a duration of 2.5 to 3.5 hours.

[0053] It should be noted that, unless otherwise specified, the present invention does not have special requirements for the impregnation treatment, the first mixing, the second mixing, the third mixing, the fourth mixing, and the mixing temperature and time of the zinc salt solution I and the copper salt solution I. Any temperature known in the art can be used. The above temperatures are each preferably 10~30℃, and more preferably room temperature. The above mixing times are all known in the art, as long as the substances can be mixed evenly.

[0054] In this invention, room temperature refers to 25±2℃.

[0055] A second aspect of the present invention is to provide modified activated carbon prepared by the preparation method described in the first aspect above.

[0056] A third aspect of the present invention is to provide the application of the modified activated carbon described in the second aspect above for adsorbing organic sulfur odorous gases.

[0057] As a preferred embodiment, the modified activated carbon is used to adsorb thiols and thioethers. More preferably, it is used to adsorb thioethers. The inventors have found that the modified activated carbon provided by the present invention has a better adsorption effect on thioethers.

[0058] Compared with the prior art, the present invention has at least the following advantages:

[0059] (1) The present invention uses the sol-gel method to modify zinc oxide and copper metal by loading them onto alkali-treated granular activated carbon, thereby obtaining modified activated carbon with a large adsorption capacity for thiols and thioethers. Detailed Implementation

[0060] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0061] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative effort are still within the scope of protection of the present invention.

[0062] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0063] Activated carbon: Coal-based columnar granular activated carbon, particle size 3 mm, iodine adsorption value ≥800 mg / g, specific surface area ≥800 m² 2 / g, bulk density 400 g / L, moisture ≤5%, purchased from Hunan Ruifeixiang Hardware Products Co., Ltd.

[0064] In the following examples, all tests were conducted at room temperature unless otherwise specified.

[0065] Example 1

[0066] (1) Prepare 1 L of 20 wt% KOH solution, immerse 500 mL of activated carbon in the solution for 24 h, then wash with deionized water until the pH value no longer changes, and dry at 105 °C to constant weight to obtain intermediate activated carbon.

[0067] (2) Prepare 100 ml of 0.6 mol / L zinc acetate solution, add 2 mL of Tween 80 as a surfactant to obtain mixture I; prepare 300 ml of oxalic acid ethanol solution, in which the oxalic acid concentration is 0.6 mol / L;

[0068] (3) Heat the mixture I obtained in step (2) and the oxalic acid ethanol solution to 70 °C respectively. Then, according to the molar ratio of zinc to oxalic acid of 1:3, pour the oxalic acid ethanol solution into the mixture I, stir evenly, and let it stand for 1 hour to obtain sol 1.

[0069] (4) Prepare 100 ml of 0.6 mol / L copper acetate solution, add 2 mL of Tween 80 as a surfactant to obtain mixture II; prepare 300 ml of oxalic acid ethanol solution, in which the oxalic acid concentration is 0.6 mol / L;

[0070] (5) Heat the mixture II obtained in step (4) and the oxalic acid ethanol solution to 70 °C respectively. Then, according to the molar ratio of zinc to oxalic acid of 1:3, pour the oxalic acid ethanol solution into the mixture II, stir evenly, and let it stand for 1 hour to obtain sol 2.

[0071] (6) Take 250 ml each of sol 1 and sol 2 and mix them with 500 mL of intermediate activated carbon obtained in step (1), and then dry them at 105 °C to constant weight;

[0072] (7) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain modified activated carbon product 1.

[0073] Example 2

[0074] Step (1) is the same as in Example 1;

[0075] (2) Prepare 500 mL of impregnation solution, in which the concentration of zinc acetate is 0.075 mol / L and the concentration of copper acetate is 0.075 mol / L;

[0076] (3) Mix 500 mL of intermediate activated carbon obtained in step (1) with the impregnation solution in step (2) and stir, then dry at 105 °C to constant weight;

[0077] (4) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain modified activated carbon product 2.

[0078] Example 3

[0079] Steps (1) to (5) are the same as in Example 1;

[0080] Step (6): Take 166 mL of sol 1 and 334 mL of sol 2 (keeping the total volume of sol 1 and sol 2 to 500 mL), mix and stir with 500 mL of intermediate activated carbon obtained in step (1), and then dry at 105 °C to constant weight;

[0081] (7) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain modified activated carbon product 3.

[0082] Example 4

[0083] Steps (1) to (5) are the same as in Example 1;

[0084] Step (6): Take 334 mL of sol 1 and 166 mL of sol 2 (keeping the total volume of sol 1 and sol 2 to 500 mL), mix and stir with 500 mL of intermediate activated carbon obtained in step (1), and then dry at 105 °C to constant weight;

[0085] (7) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain modified activated carbon product 4.

[0086] Example 5

[0087] Step (1) is the same as in Example 1;

[0088] (2) Prepare 100 ml of 0.6 mol / L zinc acetate solution, add 2 mL of Tween 80 as a surfactant to obtain mixture I; prepare 300 ml of oxalic acid ethanol solution, in which the oxalic acid concentration is 0.6 mol / L;

[0089] (3) Mix the mixture I obtained in step (2) with the oxalic acid ethanol solution at a molar ratio of zinc to oxalic acid of 1:3, stir, heat to 70 °C, and let stand for 1 h to obtain sol 1;

[0090] (4) Prepare 100 ml of 0.6 mol / L copper acetate solution, add 2 mL of Tween 80 as a surfactant to obtain mixture II; prepare 300 ml of oxalic acid ethanol solution, in which the oxalic acid concentration is 0.6 mol / L;

[0091] (5) Mix the mixture II obtained in step (4) with the oxalic acid ethanol solution in a ratio of zinc to oxalic acid of 1:3, stir, heat to 70 °C, and let stand for 1 h to obtain sol 2;

[0092] (6) Take 250 ml each of sol 1 and sol 2 and mix them with 500 mL of intermediate activated carbon obtained in step (1), and then dry them at 105 °C to constant weight;

[0093] (7) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain modified activated carbon product 5.

[0094] Comparative Example 1

[0095] Steps (1) to (3) are the same as in Example 1;

[0096] (4) Take 500 ml of sol 1 and mix it with 500 mL of intermediate activated carbon obtained in step (1), and then dry it at 105 °C to constant weight;

[0097] (5) Place the dried product in a quartz tube furnace and calcine it at 450 °C for 3 h under N2 atmosphere. After cooling, take it out to obtain the modified activated carbon product D-1.

[0098] Comparative Example 2

[0099] Step (1) is the same as in Example 1;

[0100] (2) Prepare 100 ml of 0.6 mol / L copper acetate solution, add 2 mL of Tween 80 as a surfactant to obtain mixture II; prepare 300 ml of oxalic acid ethanol solution, in which the concentration of oxalic acid is 0.6 mol / L;

[0101] (3) Heat the mixture II obtained in step (2) and the oxalic acid ethanol solution to 70 °C respectively. Then, according to the molar ratio of zinc to oxalic acid of 1:3, pour the oxalic acid ethanol solution into the mixture II, stir evenly, and let it stand for 1 hour to obtain sol 2.

[0102] (6) Take 500 mL of sol 2 and mix it with 500 mL of intermediate activated carbon obtained in step (1), and then dry it at 105 °C to constant weight;

[0103] (7) The dried product was placed in a quartz tube furnace and calcined at 450 °C for 3 h under N2 atmosphere. After cooling, it was taken out to obtain the modified activated carbon product D-2.

[0104] Test case

[0105] The modified activated carbon products prepared in the above examples were subjected to dimethyl disulfide adsorption tests. The specific method was as follows: 200g of the modified activated carbon product was packed into a φ50×400 mm adsorption column, and dimethyl disulfide gas with a concentration of 50~100 ppm was introduced at a gas flow rate of 4 m / s. 3 The gas flow was stopped at a rate of / h when dimethyl disulfide gas was detected at the outlet of the adsorption column, and the weight of the activated carbon after adsorption was measured. The specific results are as follows:

[0106] The modified activated carbon product 1 has an adsorption capacity of 205 mg / g for dimethyl disulfide.

[0107] The modified activated carbon product 2 has an adsorption capacity of 181.4 mg / g for dimethyl disulfide.

[0108] The modified activated carbon product 3 has an adsorption capacity of 191.2 mg / g for dimethyl disulfide.

[0109] The modified activated carbon product 4 has an adsorption capacity of 184.7 mg / g for dimethyl disulfide.

[0110] The modified activated carbon product 5 has an adsorption capacity of 194.6 mg / g for dimethyl disulfide.

[0111] The modified activated carbon product D-1 has an adsorption capacity of 81.6 mg / g for dimethyl disulfide.

[0112] The modified activated carbon product D-2 has an adsorption capacity of 89.3 mg / g for dimethyl disulfide.

[0113] The modified activated carbon product prepared in Example 1 was subjected to an ethanethiol adsorption test. The specific method was as follows: 200g of the modified activated carbon product was packed into a φ50×400 mm adsorption column, and ethanethiol gas with a concentration of 50~100 ppm was introduced at a gas flow rate of 4 m / s. 3 The gas flow was stopped at the outlet of the adsorption column at a rate of / h. The weight of the activated carbon after adsorption was measured. The specific results are as follows: Modified activated carbon product 1 has an adsorption capacity of 108.7 mg / g for ethanethiol.

[0114] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a modified activated carbon, characterized by: The method comprises: (1) impregnating the activated carbon in lye to obtain intermediate activated carbon; (2) mixing and stirring the intermediate activated carbon with the impregnating solution, and then drying and calcining to obtain the modified activated carbon; The calcining temperature is 420-480℃; The impregnating solution contains copper source and zinc source.

2. The method for preparing modified activated carbon according to claim 1, characterized in that: The molar ratio of zinc in the zinc source to copper in the copper source in the impregnating solution is 1:0.5-2; And / or, the volume ratio of the intermediate activated carbon to the impregnating solution is 1:0.8-1.2; And / or, the lye is potassium hydroxide solution and / or sodium hydroxide solution.

3. The method for preparing modified activated carbon according to claim 1 or 2, characterized in that: The preparation method of the impregnating solution comprises scheme (a) or scheme (b): Scheme (a): mixing zinc salt solution I and copper salt solution I to obtain the impregnating solution; Scheme (b): first mixing zinc salt solution II and surfactant I to obtain sol 1, and then second mixing sol 1 and alcohol solution I to obtain sol 2, wherein the alcohol solution I contains diacid and / or polyacid; And, third mixing copper salt solution II and surfactant II to obtain sol 2, and then fourth mixing sol 2 and alcohol solution II to obtain sol 2, wherein the alcohol solution II contains diacid and / or polyacid; After mixing the sol 1 and the sol 2, the impregnating solution is obtained.

4. The method for preparing modified activated carbon according to claim 3, characterized in that: In scheme (a), the impregnating solution contains 0.07-0.08 mol / L zinc acetate and 0.035-0.16 mol / L copper acetate.

5. The method for preparing modified activated carbon according to claim 3, characterized in that: In scheme (b), the surfactant I and the surfactant II are independently Tween 80 and / or polyethylene glycol; And / or, in scheme (b), the zinc salt solution II is 0.5-0.7 mol / L zinc acetate solution; And / or, in scheme (b), the copper salt solution II is 0.5-0.7 mol / L copper acetate solution.

6. A method for preparing modified activated carbon according to claim 3 or 5, characterized in that: The alcohol solution I contains oxalic acid, and the concentration of the oxalic acid in the alcohol solution I is 0.5-0.7 mol / L; And / or, the alcohol solution II contains oxalic acid, and the concentration of the oxalic acid in the alcohol solution II is 0.5-0.7 mol / L.

7. A method for preparing modified activated carbon according to claim 3 or 5, characterized in that: The ratio of the total molar amount of diacid and polyacid in the alcohol solution I to the molar amount of zinc in the zinc salt solution II is 3.5-2.5:1; The ratio of the total molar amount of diacid and polyacid in the alcohol solution II to the molar amount of copper in the copper salt solution II is 3.5-2.5:

1.

8. The method for preparing modified activated carbon according to claim 3, characterized in that: The method of scheme (b) further comprises: After first mixing the zinc salt solution II and the surfactant I, the obtained mixed solution and the alcohol solution I are heated to 65-75℃ respectively, and then second mixing the heated mixed solution and the heated alcohol solution I to obtain sol 1 after standing for 50-80 min; After third mixing the copper salt solution II and the surfactant II, the obtained mixed solution and the alcohol solution II are heated to 65-75℃ respectively, and then fourth mixing the heated mixed solution and the heated alcohol solution II to obtain sol 2 after standing for 50-80 min.

9. The modified activated carbon prepared by the preparation method of any one of claims 1-9.

10. Use of the modified activated carbon according to claim 9 for adsorbing organic sulfur malodorous gases.