Modified activated carbon for removing perchlorate in water for sheep farming and method for preparing the same
By introducing carboxyl groups, quaternary ammonium salts, and triethylenetetramine onto the surface of activated carbon through multi-step modification, its electrostatic adsorption capacity is enhanced, solving the problem of low perchlorate removal efficiency of activated carbon in sheep farm water, and achieving efficient, safe, and low-cost pollutant removal.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHAANXI UNIV OF SCI & TECH
- Filing Date
- 2024-12-30
- Publication Date
- 2026-06-26
Smart Images
Figure CN119633761B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water treatment, and more specifically, to a modified activated carbon for removing perchlorate from water used in sheep farms and its preparation method. Background Technology
[0002] Perchlorate (ClO4) - As a novel pollutant, perchlorate is highly water-soluble and persistent, and can directly affect human health through drinking water. Perchlorate can interfere with the thyroid gland's absorption of iodine, thereby affecting the normal secretion of thyroid hormones, and is particularly harmful to the brain development of fetuses and infants. Therefore, effectively controlling perchlorate pollution in dairy products has become a crucial issue that urgently needs to be addressed.
[0003] Currently, adsorption is the primary technology for removing perchlorate from water used in sheep farms. Activated carbon, due to its low cost, ease of operation, and lack of secondary pollution, has become the most widely used adsorbent to address perchlorate pollution problems in sheep farms. Activated carbon has a large specific surface area and a good pore structure, enabling it to adsorb various harmful substances, and is widely used, especially in water treatment. However, the adsorption efficiency of traditional activated carbon is limited by several factors and cannot fully meet the requirements for perchlorate removal. Furthermore, other removal methods such as ion exchange, membrane filtration, and chemical reduction, while achieving some degree of perchlorate removal, are costly and complex, making them difficult to widely implement in large-scale farms. Therefore, activated carbon remains an important choice for perchlorate treatment in sheep farms at present.
[0004] However, directly using traditional activated carbon to treat perchlorate in livestock farms still has many drawbacks. On the one hand, unmodified activated carbon has weak electrostatic adsorption capacity, resulting in limited removal efficiency for perchlorate. On the other hand, while modified activated carbon can effectively improve adsorption performance, its preparation process is complex and costly, making it difficult to meet the actual needs of large-scale livestock farms. Furthermore, currently available modified activated carbon is prone to adsorption saturation and shedding during use, leading to a shortened service life and low utilization value. Therefore, there is currently no efficient, safe, low-cost modified activated carbon material suitable for sheep farms. Summary of the Invention
[0005] To address the problems existing in the prior art, this invention provides a modified activated carbon for removing perchlorate from water in sheep farms and its preparation method, thereby solving the problems of limited effectiveness, complex preparation process, high cost, and short service life of current activated carbon in removing perchlorate from water in sheep farms. It significantly enhances the adsorption capacity of activated carbon for negatively charged solutes and improves the overall treatment efficiency of perchlorate in the farm environment.
[0006] This invention is achieved through the following technical solution:
[0007] A method for preparing modified activated carbon for removing perchlorate from water in sheep farms includes the following steps:
[0008] S1, Activated carbon is reacted in citric acid aqueous solution, and a carboxyl base layer is uniformly loaded on the surface of the activated carbon to obtain preliminarily modified activated carbon;
[0009] S2, the preliminarily modified activated carbon is reacted in an alkaline aqueous solution of polydimethyldiallylammonium chloride, and the strong cationic quaternary ammonium salt is adsorbed on the surface of the carboxyl substrate through electrostatic interaction to obtain the re-modified activated carbon.
[0010] S3, the modified activated carbon is reacted in a triethylenetetramine aqueous solution, so that the triethylenetetramine molecules are further bound to the strong cationic quaternary ammonium salt through electrostatic adsorption, to obtain modified activated carbon for removing perchlorate from water in sheep farms.
[0011] A further improvement of the present invention is that:
[0012] S1. Activated carbon is added to a citric acid aqueous solution and mixed evenly. Then, it is stirred at 40-60°C for 2-4 hours. Unadsorbed citric acid is then removed to obtain preliminarily modified activated carbon.
[0013] The mass ratio of citric acid to deionized water in the citric acid aqueous solution is (1.92-4.8):50, and the mass ratio of activated carbon to citric acid is 1:(1.92-4.8).
[0014] S2. The preliminarily modified activated carbon is added to an aqueous solution of polydimethyldiallyl ammonium chloride, the pH of the solution is adjusted to alkaline, and then stirred at 40-60°C for 3-5 hours. The unadsorbed polydimethyldiallyl ammonium chloride is then removed to obtain the re-modified activated carbon.
[0015] The volume ratio of polydimethyldiallyl ammonium chloride to deionized water in the aqueous solution is 1:(2-4), and the ratio of preliminarily modified activated carbon to the aqueous solution of polydimethyldiallyl ammonium chloride is 1g:30mL.
[0016] S2 adjusts the pH of the solution to 8.5-11, and then stirs it at 40-60°C for 3-5 hours.
[0017] S3 adds the re-modified activated carbon to a triethylenetetramine aqueous solution, then stirs at 20-40°C for 3-5 hours, removes unbound triethylenetetramine, and finally dries to obtain modified activated carbon for removing perchlorate from water used in sheep farms.
[0018] The volume ratio of triethylenetetramine to deionized water in the triethylenetetramine aqueous solution is 1:(2-7), and the ratio of the re-modified activated carbon to the triethylenetetramine aqueous solution is 1g:50mL.
[0019] The stirring intensity in S1 is 40-80 r / min, and the stirring intensity in S2 and S3 is 60-80 r / min.
[0020] A modified activated carbon obtained by the preparation method of the modified activated carbon for removing perchlorate from water in sheep farms as described in any one of the above-mentioned methods.
[0021] Compared with the prior art, the present invention has the following beneficial technical effects:
[0022] This invention discloses a method for preparing modified activated carbon for removing perchlorate from water used in sheep farms. The method involves a multi-step modification of the activated carbon surface, sequentially introducing carboxyl groups, quaternary ammonium salts, and layering modifiers to enhance the adsorption capacity of the activated carbon. First, citric acid solution is reacted with the activated carbon, introducing carboxyl groups through citric acid. Citric acid molecules then bind to oxygen-containing groups on the activated carbon surface via hydrogen bonds, uniformly loading a carboxyl layer onto the activated carbon surface. This increases the number of oxygen-containing functional groups on the activated carbon surface and improves the binding force of subsequent modifications. Next, polydimethyldiallylammonium chloride solution is reacted with the pre-modified activated carbon, allowing the strong cationic quaternary ammonium salt to be adsorbed onto the carboxyl layer on the activated carbon through electrostatic interactions. Finally, triethylenetetramine solution is reacted with the further modified activated carbon, allowing triethylenetetramine molecules to further bind to the strong cationic quaternary ammonium salt layer through electrostatic adsorption. The quaternary ammonium salt polymer polydimethyldiallylammonium chloride and the layering modifier triethylenetetramine were electrostatically modified to introduce strong cationic functionality and more adsorption sites. On the one hand, the positively charged nitrogen-containing functional groups in the quaternary ammonium salt exhibit strong electrostatic adsorption of negatively charged perchlorate, effectively adsorbing perchlorate from aqueous solutions. On the other hand, the layering modifier formed a stronger electrostatic interaction with the strong cationic quaternary ammonium salt layer, further enhancing the electrostatic adsorption attraction on the activated carbon surface. Overall, this significantly improved the removal efficiency of negatively charged pollutants such as perchlorate. The adsorption capacity of the modified activated carbon was 36.24-40.01 mg / L, with a maximum of 40.01 mg / L, achieving highly efficient, safe, and suitable adsorption for perchlorate pollution problems in sheep farms. Citric acid dissociates into a negative charge under alkaline conditions, which can form a stronger electrostatic interaction with the positively charged quaternary ammonium groups, increasing the adhesion and stability of the quaternary ammonium salt polymer on the activated carbon surface. The preparation method is simple, with low production costs, and suitable for on-site use in livestock farms. Meanwhile, activated carbon can be reused multiple times through simple regeneration, reducing operating costs. The preparation process uses water as the reaction medium, avoiding the emission of harmful substances, making it environmentally friendly to the surrounding environment of sheep farms and in line with green environmental protection concepts. Attached Figure Description
[0023] Figure 1 The graph shows the adsorption capacity of the modified activated carbon in Examples 1-6. Detailed Implementation
[0024] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.
[0025] This invention provides a method for preparing modified activated carbon for removing perchlorate from water in sheep farms, comprising the following steps:
[0026] Step 1: Modify the surface of activated carbon with citric acid:
[0027] Prepare a citric acid solution by mixing citric acid with deionized water, add activated carbon to the citric acid solution, mix well, and stir at 40-60°C for 2-4 hours.
[0028] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0029] Use magnetic stirring, controlling the magnetic stirring intensity at 40-80 r / min.
[0030] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of (1.92-4.80):50, and activated carbon was prepared at a mass ratio of 1:(1.92-4.80).
[0031] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0032] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride with deionized water. Modified activated carbon was then added to the polydimethyl diallyl ammonium chloride solution, and the pH of the solution was adjusted to alkaline. The solution was stirred at 40-60°C for 3-5 hours.
[0033] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0034] Use magnetic stirring and control the stirring intensity at 60-80 r / min.
[0035] The pH of the polydimethyldiallylammonium chloride solution is 8.5-11.
[0036] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride with deionized water at a volume ratio of 1:(2-4). The ratio of modified activated carbon to the prepared polydimethyl diallyl ammonium chloride aqueous solution was 1g:30mL.
[0037] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0038] Triethylenetetramine is mixed with deionized water to prepare a triethylenetetramine solution. Modified activated carbon is then added to the triethylenetetramine solution and stirred at 20-40°C for 3-5 hours.
[0039] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0040] Use magnetic stirring and control the stirring intensity at 60-80 r / min.
[0041] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:(2-7). The ratio of modified activated carbon to the prepared triethylenetetramine solution was 1g:50mL.
[0042] Step 4, drying:
[0043] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0044] The activated carbon can be selected from one of the following: coal-based activated carbon, coconut shell activated carbon, or wood-based activated carbon. Preferably, coconut shell activated carbon is selected.
[0045] Example 1
[0046] Step 1: Modify the surface of activated carbon with citric acid:
[0047] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 1.92:50. 1g of coconut shell activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 60r / min for 2 hours at 60°C.
[0048] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0049] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0050] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride and deionized water at a volume ratio of 1:2. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 8.5, and the solution was magnetically stirred at 60 r / min for 3 hours at 60°C.
[0051] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0052] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0053] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:2. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 80 r / min for 3 hours at 20°C.
[0054] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0055] Step 4, drying:
[0056] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0057] Example 2
[0058] Step 1: Modify the surface of activated carbon with citric acid:
[0059] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 3.36:50. 1g of wood-based activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 60r / min for 2 hours at 60°C.
[0060] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0061] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0062] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride and deionized water at a volume ratio of 1:2. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 9, and the solution was magnetically stirred at 60 r / min for 3 hours at 60°C.
[0063] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0064] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0065] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:3. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 80 r / min for 3 hours at 20°C.
[0066] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0067] Step 4, drying:
[0068] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0069] Example 3
[0070] Step 1: Modify the surface of activated carbon with citric acid:
[0071] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 4.80:50. 1g of coal-based activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 70r / min for 3 hours at 50°C.
[0072] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0073] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0074] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride with deionized water at a volume ratio of 1:2. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 9.5, and the solution was magnetically stirred at 70 r / min for 4 hours at 50°C.
[0075] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0076] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0077] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:4. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 70 r / min for 4 hours at 30°C.
[0078] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0079] Step 4, drying:
[0080] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0081] Example 4
[0082] Step 1: Modify the surface of activated carbon with citric acid:
[0083] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 1.92:50. 1g of coconut shell activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 70r / min for 3 hours at 50°C.
[0084] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0085] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0086] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride and deionized water at a volume ratio of 1:4. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 10, and the solution was magnetically stirred at 70 r / min for 4 hours at 50°C.
[0087] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0088] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0089] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:5. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 70 r / min for 4 hours at 30°C.
[0090] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0091] Step 4, drying:
[0092] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0093] Example 5
[0094] Step 1: Modify the surface of activated carbon with citric acid:
[0095] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 3.36:50. 1g of coconut shell activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 80r / min for 4 hours at 40°C.
[0096] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0097] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0098] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride with deionized water at a volume ratio of 1:4. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 10.5, and the solution was magnetically stirred at 80 r / min for 4 hours at 40°C.
[0099] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0100] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0101] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:6. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 60 r / min for 5 hours at 40°C.
[0102] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0103] Step 4, drying:
[0104] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0105] Example 6
[0106] Step 1: Modify the surface of activated carbon with citric acid:
[0107] Citric acid solution was prepared by mixing citric acid and deionized water at a mass ratio of 4.80:50. 1g of coconut shell activated carbon was added to 50mL of citric acid solution, mixed evenly, and then magnetically stirred at 80r / min for 4 hours at 40°C.
[0108] After the reaction is complete, filter and rinse with deionized water until the pH of the filtrate is neutral to remove unadsorbed citric acid.
[0109] The second step is to introduce quaternary ammonium salt polymers to increase the electrostatic adsorption capacity of activated carbon:
[0110] A polydimethyl diallyl ammonium chloride solution was prepared by mixing polydimethyl diallyl ammonium chloride and deionized water at a volume ratio of 1:4. 1 g of modified activated carbon was added to 30 mL of the polydimethyl diallyl ammonium chloride solution, the pH of the solution was adjusted to 11, and the solution was magnetically stirred at 80 r / min for 4 hours at 40°C.
[0111] After the reaction is complete, the solution is filtered and rinsed with deionized water until the pH of the filtrate is neutral to remove unadsorbed polydimethyldiallyl ammonium chloride.
[0112] The third step involves using layered modifiers to further enhance the electrostatic adsorption capacity of activated carbon.
[0113] A triethylenetetramine solution was prepared by mixing triethylenetetramine with deionized water at a volume ratio of 1:7. 1 g of modified activated carbon was added to 50 mL of the triethylenetetramine solution, and the mixture was magnetically stirred at 60 r / min for 5 hours at 40°C.
[0114] After the reaction was completed, the sample was filtered and rinsed thoroughly with deionized water until the pH of the filtrate was neutral to remove unbound triethylenetetramine and ensure the stability of the surface modification.
[0115] Step 4, drying:
[0116] The modified activated carbon was obtained by drying it in a vacuum drying oven at 50°C for 24 hours.
[0117] Adsorption performance tests of Examples 1-6
[0118] The modified activated carbon prepared in Examples 1-6 above was used to adsorb in perchlorate solution to investigate its adsorption performance. The specific steps are as follows:
[0119] To prepare a 50 mg / L perchlorate solution: Place a 1000 mg / L standard concentration perchlorate solution in a beaker and dilute it with acetonitrile at a volume ratio of 1:19 to obtain a 50 mg / L perchlorate solution. Inject the prepared perchlorate solution into a sample tube using a disposable syringe filter as a blank control.
[0120] Simulated adsorption process: 1g of activated carbon was packed into a 5mL syringe and compacted. A 50mg / L perchlorate solution was added from the top of the syringe. The adsorbed perchlorate solution was then injected into a sample tube using a disposable syringe filter, and the perchlorate concentration in the sample solution was measured.
[0121] The modified activated carbons of Examples 1-6 were used to adsorb perchlorate. Each sample was measured in parallel three times, and the maximum adsorption capacity of each modified activated carbon was taken as the final adsorption capacity.
[0122] The experimental results are shown in Figure 1The adsorption capacity refers to the maximum amount of perchlorate adsorbed per unit dose (per gram) of modified activated carbon (unit: mg / L).
[0123] from Figure 1 As can be seen, the maximum adsorption capacity of the present invention reaches 40.01 mg / L, and the perchlorate removal rate reaches 80.02% compared with the unadsorbed perchlorate solution. Therefore, the method of the present invention can effectively remove perchlorate, and has a large adsorption capacity and good adsorption effect.
Claims
1. A method for preparing modified activated carbon for removing perchlorate from water in sheep farms, characterized in that, Includes the following steps: S1. Activated carbon is added to a citric acid aqueous solution and mixed evenly. The mass ratio of citric acid to deionized water in the citric acid aqueous solution is (1.92-4.8):50, and the mass ratio of activated carbon to citric acid is 1:(1.92-4.8). Then, the mixture is stirred at 40-60°C for 2-4 hours to uniformly load a carboxyl layer on the surface of the activated carbon. The unadsorbed citric acid is then removed to obtain preliminarily modified activated carbon. S2, the preliminarily modified activated carbon is added to an aqueous solution of polydimethyl diallyl ammonium chloride, the volume ratio of polydimethyl diallyl ammonium chloride to deionized water in the aqueous solution of polydimethyl diallyl ammonium chloride is 1:(2-4), the ratio of preliminarily modified activated carbon to aqueous solution of polydimethyl diallyl ammonium chloride is 1g:30mL, the pH of the solution is adjusted to 8.5-11, and then stirred at 40-60°C for 3-5h. The strong cationic quaternary ammonium salt is adsorbed on the surface of the carboxyl substrate by electrostatic interaction, and then the unadsorbed polydimethyl diallyl ammonium chloride is removed to obtain the re-modified activated carbon; S3. The modified activated carbon is added to a triethylenetetramine aqueous solution. The volume ratio of triethylenetetramine to deionized water in the triethylenetetramine aqueous solution is 1:(2-7), and the ratio of the modified activated carbon to the triethylenetetramine aqueous solution is 1g:50mL. Then, the mixture is stirred at 20-40°C for 3-5 hours to allow the triethylenetetramine molecules to further bind to the strong cationic quaternary ammonium salt through electrostatic adsorption. The unbound triethylenetetramine is then removed, and the mixture is finally dried to obtain modified activated carbon for removing perchlorate from water used in sheep farms.
2. The method for preparing modified activated carbon for removing perchlorate from water in sheep farms according to claim 1, characterized in that, The stirring intensity in S1 is 40-80 r / min, and the stirring intensity in S2 and S3 is 60-80 r / min.
3. A modified activated carbon obtained by the preparation method of the modified activated carbon for removing perchlorate from water in sheep farms as described in any one of claims 1-2.