Activated carbon composite polymeric flocculant for water pollution

Abstract

The invention discloses an activated carbon composite polymeric flocculant for water pollution, and relates to the technical field of sewage treatment materials.According to the activated carbon composite polymeric flocculant for water pollution, walnut shells are used for preparing biochar, then the biochar and metal hydroxides are compounded, the adsorption performance of a compound is enhanced, then polydopamine is used for coating the compound, the hydrophilic performance of the compound is improved, and the adsorption performance of the compound is improved; the chelating capability with heavy metals can be enhanced, and the sewage treatment performance is further enhanced. Chitosan is subjected to microspheroidizing treatment, the specific surface area after microspheroidizing is remarkably increased, amido, hydroxyl and other groups on chitosan are reserved in microspheres, more acrylic acid copolymers can be grafted, heavy metal ions and soluble organic pollutants can be adsorbed, the flocculation speed is high, and the sewage treatment performance is good.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment materials, in particular to an activated carbon composite polymer flocculant for water pollution. Background Art

[0002] Flocculants can be widely used in the deep purification treatment of municipal sewage, industrial wastewater, and contaminated surface water. Activated carbon has long been used as an adsorbent to remove heavy metal ions, organic pollutants, and other substances from water bodies due to its well-developed pore structure and large specific surface area. However, activated carbon has a limited removal rate for pollutants in the form of colloids, emulsified oils, and tiny suspended particles. Furthermore, when used alone, activated carbon is not ideal for removing soluble pollutants such as total phosphorus and total nitrogen. The combination of activated carbon and polymer flocculants is a common process in the prior art, but activated carbon and flocculants are prone to dissociation, resulting in poor stability and poor sewage treatment capacity.

[0003] In order to solve the above problems and improve sewage treatment capacity, the present invention provides an activated carbon composite polymer flocculant for water pollution. Summary of the Invention

[0004] The purpose of the present invention is to provide an activated carbon composite polymer flocculant for water pollution, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions: The invention discloses an activated carbon composite polymer flocculant for water pollution, comprising the following components, calculated by weight: 3-5 parts of activated carbon, 7-10 parts of chitosan-acrylic acid copolymer, 8-10 parts of modified biochar-metal hydroxide complex, 6-7 parts of sodium lignin sulfonate, 5-8 parts of polyvinyl pyrrolidone, 4-6 parts of ethyl acetate, and 5-6 parts of anhydrous ferric chloride.

[0006] More optimally, the preparation method of the modified biochar-metal hydroxide complex is: take trihydroxyaminomethane and deionized water, stir evenly, add hydrochloric acid solution dropwise, adjust the pH to 8.5, add the biochar-metal hydroxide complex, ultrasonically disperse for 30-40 minutes, add dopamine hydrochloride, ultrasonically disperse for 10-20 minutes, then stir for 10-14 hours, filter, wash, and dry to obtain the modified biochar-metal hydroxide complex.

[0007] More optimally, the method for preparing the biochar-metal hydroxide composite comprises the following steps: Step 1: Take aluminum chloride hexahydrate and magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take sodium hydroxide solution, sodium carbonate solution, and deionized water, stir them evenly to obtain a mixed solution B; Step 2: Take walnut shell biochar and mixed solution A, add mixed solution B dropwise while stirring, stir for 3-4 hours, heat to 85-87°C and react for 9-10 hours, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex.

[0008] More optimally, the preparation method of the walnut shell biochar is as follows: take walnut shells, dry and crush them, and pass them through a 100-mesh sieve to obtain walnut shell powder; take walnut shell powder and sulfuric acid, stir for 3-4 hours, react for 20-22 hours, wash and dry, and then pyrolyze at 300°C under nitrogen protection, add potassium hydroxide, pyrolyze at 600°C under nitrogen protection for 5-6 hours, add hydrochloric acid solution and soak for 10-12 hours, wash and dry to obtain walnut shell biochar.

[0009] More optimally, the preparation method of the chitosan-acrylic acid copolymer is as follows: taking acrylamide and deionized water, stirring evenly to obtain an acrylamide solution; taking chitosan and acrylic acid solution, stirring evenly, adding cerium ammonium nitrate solution under nitrogen protection, stirring for 30-40 minutes, adding acrylamide solution dropwise, reacting at 50-55°C with microwave for 12-15 minutes, taking out, and cooling to room temperature to obtain chitosan-acrylic acid copolymer.

[0010] More optimally, the chitosan is chitosan microspheres, and the preparation method of the chitosan microspheres is: take chitosan powder and acetic acid solution, heat to 70-72°C, stir for 2-2.5 hours to obtain a chitosan solution, squeeze the chitosan solution into a sodium tripolyphosphate solution and solidify for 10-14 hours, wash, add to a glutaraldehyde solution, heat to 45-50°C and oscillate for 6-7 hours, oscillate for 10-12 hours, wash, and dry to obtain amino chitosan microspheres.

[0011] More optimally, the chitosan microspheres are amino chitosan microspheres, and the preparation method thereof is as follows: chitosan powder and acetic acid solution are taken, heated to 70-72°C, stirred for 2-2.5 hours to obtain a chitosan solution, the chitosan solution is squeezed into a sodium tripolyphosphate solution and solidified for 10-14 hours, washed, added to a glutaraldehyde solution, heated to 45-50°C and shaken for 6-7 hours, diethylenetriamine is added dropwise, shaken for 10-12 hours, washed, and dried to obtain amino chitosan microspheres.

[0012] More optimally, the preparation method of the activated carbon composite polymer flocculant for water pollution is: take activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride, stir evenly to obtain the activated carbon composite polymer flocculant for water pollution.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses walnut shells to prepare biochar, and then composites the biochar with metal hydroxides to enhance the adsorption performance of the composite. Subsequently, polydopamine is used to coat the composite, which improves its hydrophilicity and enhances its chelating ability with heavy metals, further enhancing sewage treatment performance.

[0014] 2. The present invention performs microspheroidization on chitosan. After microspheroidization, the specific surface area is significantly increased. The amino groups, hydroxyl groups and other groups on the chitosan are retained inside the microspheres, and more acrylic acid copolymers can be grafted. Heavy metal ions and soluble organic pollutants can be adsorbed, and the flocculation speed is fast.

[0015] 3. The present invention coats chitosan with an acrylic acid copolymer and grafts polymer chains onto the chitosan surface, achieving strong charge neutralization and improving flocculation capacity. The present invention also adds diethylenetriamine to amino-modify the chitosan microspheres, improving the compatibility of the chitosan-acrylic acid copolymer and the modified biochar-metal hydroxide complex, enhancing flocculation capacity, and improving the sedimentation effect of the modified biochar-metal hydroxide complex, thereby further enhancing sewage treatment performance. DETAILED DESCRIPTION

[0016] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0017] The sources and models of the raw materials involved in the present invention are not particularly limited, and illustratively include: walnut shells: from Yingyeer Township, Yining City, Xinjiang Uygur Autonomous Region; polyvinyl pyrrolidone: can be purchased from Sigma-Aldrich, model: 81420; activated carbon: 200 mesh, can be purchased from Suzhou Xufeng Activated Carbon Co., Ltd.

[0018] Example 1: A method for preparing an activated carbon composite polymer flocculant for water pollution comprises the following steps: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 3.5 h, reacted for 21 h, washed, dried, and then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 5.5 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 11 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar-metal hydroxide composite: Take 50 mL of 0.1 mol / L aluminum chloride hexahydrate and 150 mL of 0.3 mol / L magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take 20 g of 2 mol / L sodium hydroxide solution, 26 g of 1 mol / L sodium carbonate solution, and 300 mL of deionized water, stir them evenly to obtain a mixed solution B; Take 1.2 g of walnut shell biochar and 100 mL of mixed solution A, add mixed solution B dropwise while stirring, stir for 3.5 h, heat to 86 ° C and react for 9.5 h, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex; Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise, adjust the pH to 8.5, add 10g of biochar-metal hydroxide complex, ultrasonically disperse for 35min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 15min, then stir for 12h, filter, wash, and dry to obtain a modified biochar-metal hydroxide complex; Step 3: Preparation of chitosan-acrylic acid copolymer: Take 2g of chitosan powder and 40mL of 2% acetic acid solution, heat to 71℃, stir for 2.3h to obtain chitosan solution, squeeze the chitosan solution into 80mL of 10% sodium tripolyphosphate solution and solidify for 12h, wash, add to 100mL of 5% glutaraldehyde solution, heat to 47℃ and shake for 6.5h, add 5mL of diethylenetriamine dropwise, shake for 11h, wash and dry to obtain amino chitosan microspheres; 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of amino-modified chitosan microspheres and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain a chitosan-acrylic acid copolymer. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen protection and stirred for 35 min. The acrylamide solution was added dropwise and microwaved at 52°C for 13 min. The mixture was removed and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 4 parts of activated carbon, 8 parts of chitosan-acrylic acid copolymer, 9 parts of modified biochar-metal hydroxide complex, 6.5 parts of sodium lignin sulfonate, 7 parts of polyvinyl pyrrolidone, 5 parts of ethyl acetate, and 5.5 parts of anhydrous ferric chloride.

[0019] Example 2: A method for preparing an activated carbon composite polymer flocculant for water pollution comprises the following steps: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 3 h, reacted for 20 h, washed, and dried. The mixture was then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 5 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 10 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar-metal hydroxide composite: Take 50 mL of 0.1 mol / L aluminum chloride hexahydrate and 150 mL of 0.3 mol / L magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take 20 g of 2 mol / L sodium hydroxide solution, 26 g of 1 mol / L sodium carbonate solution, and 300 mL of deionized water, stir them evenly to obtain a mixed solution B; Take 1.2 g of walnut shell biochar and 100 mL of mixed solution A, add mixed solution B dropwise while stirring, stir for 3 h, heat to 85 ° C and react for 9 h, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex; Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise, adjust the pH to 8.5, add 10g of biochar-metal hydroxide complex, ultrasonically disperse for 30min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 10min, then stir for 10h, filter, wash, and dry to obtain a modified biochar-metal hydroxide complex; Step 3: Preparation of chitosan-acrylic acid copolymer: Take 2g of chitosan powder and 40mL of 2% acetic acid solution, heat to 70℃, stir for 2h to obtain chitosan solution, squeeze the chitosan solution into 80mL of 10% sodium tripolyphosphate solution and solidify for 10h, wash, add to 100mL of 5% glutaraldehyde solution, heat to 45℃ and shake for 6h, add 5mL of diethylenetriamine dropwise, shake for 10h, wash and dry to obtain amino chitosan microspheres; 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of amino-modified chitosan microspheres and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain an acrylamide solution. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen and stirred for 30 min. The acrylamide solution was then added dropwise. The mixture was microwaved at 50°C for 12 min, removed, and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 3 parts of activated carbon, 7 parts of chitosan-acrylic acid copolymer, 8 parts of modified biochar-metal hydroxide complex, 6 parts of sodium lignin sulfonate, 5 parts of polyvinyl pyrrolidone, 4 parts of ethyl acetate, and 5 parts of anhydrous ferric chloride.

[0020] Example 3: A method for preparing an activated carbon composite polymer flocculant for water pollution comprises the following steps: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 4 h, reacted for 22 h, washed, and dried. The mixture was then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 6 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 12 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar-metal hydroxide composite: Take 50 mL of 0.1 mol / L aluminum chloride hexahydrate and 150 mL of 0.3 mol / L magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take 20 g of 2 mol / L sodium hydroxide solution, 26 g of 1 mol / L sodium carbonate solution, and 300 mL of deionized water, stir them evenly to obtain a mixed solution B; Take 1.2 g of walnut shell biochar and 100 mL of mixed solution A, add mixed solution B dropwise while stirring, stir for 4 h, heat to 87 ° C and react for 10 h, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex; Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise, adjust the pH to 8.5, add 10g of biochar-metal hydroxide complex, ultrasonically disperse for 40min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 20min, then stir for 14h, filter, wash, and dry to obtain a modified biochar-metal hydroxide complex; Step 3: Preparation of chitosan-acrylic acid copolymer: Take 2g of chitosan powder and 40mL of 2% acetic acid solution, heat to 72℃, stir for 2.5h to obtain chitosan solution, squeeze the chitosan solution into 80mL of 10% sodium tripolyphosphate solution and solidify for 14h, wash, add to 100mL of 5% glutaraldehyde solution, heat to 50℃ and shake for 7h, add 5mL of diethylenetriamine dropwise, shake for 12h, wash and dry to obtain amino chitosan microspheres; 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of amino-modified chitosan microspheres and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain a chitosan-acrylic acid copolymer. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen protection and stirred for 40 min. The acrylamide solution was added dropwise and microwaved at 55°C for 15 min. The mixture was removed and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 5 parts of activated carbon, 10 parts of chitosan-acrylic acid copolymer, 10 parts of modified biochar-metal hydroxide complex, 7 parts of sodium lignin sulfonate, 8 parts of polyvinyl pyrrolidone, 6 parts of ethyl acetate, and 6 parts of anhydrous ferric chloride.

[0021] Comparative Example 1: Chitosan was not amino-modified, and the rest was the same as Example 1: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 3.5 h, reacted for 21 h, washed, dried, and then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 5.5 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 11 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar-metal hydroxide composite: Take 50 mL of 0.1 mol / L aluminum chloride hexahydrate and 150 mL of 0.3 mol / L magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take 20 g of 2 mol / L sodium hydroxide solution, 26 g of 1 mol / L sodium carbonate solution, and 300 mL of deionized water, stir them evenly to obtain a mixed solution B; Take 1.2 g of walnut shell biochar and 100 mL of mixed solution A, add mixed solution B dropwise while stirring, stir for 3.5 h, heat to 86 ° C and react for 9.5 h, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex; Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise, adjust the pH to 8.5, add 10g of biochar-metal hydroxide complex, ultrasonically disperse for 35min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 15min, then stir for 12h, filter, wash, and dry to obtain a modified biochar-metal hydroxide complex; Step 3: Preparation of chitosan-acrylic acid copolymer: Take 2g of chitosan powder and 40mL of 2% acetic acid solution, heat to 71℃, stir for 2.3h to obtain chitosan solution, squeeze the chitosan solution into 80mL of 10% sodium tripolyphosphate solution and solidify for 12h, wash, add to 100mL of 5% glutaraldehyde solution, heat to 47℃ and shake for 11h, wash and dry to obtain chitosan microspheres; 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of chitosan microspheres and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain a chitosan-acrylic acid copolymer. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen and stirred for 35 min. The acrylamide solution was added dropwise and microwaved at 52°C for 13 min. The mixture was removed and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 4 parts of activated carbon, 8 parts of chitosan-acrylic acid copolymer, 9 parts of modified biochar-metal hydroxide complex, 6.5 parts of sodium lignin sulfonate, 7 parts of polyvinyl pyrrolidone, 5 parts of ethyl acetate, and 5.5 parts of anhydrous ferric chloride.

[0022] Comparative Example 2: Chitosan was used instead of chitosan microspheres, and the rest was the same as in Example 1: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 3.5 h, reacted for 21 h, washed, dried, and then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 5.5 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 11 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar-metal hydroxide composite: Take 50 mL of 0.1 mol / L aluminum chloride hexahydrate and 150 mL of 0.3 mol / L magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take 20 g of 2 mol / L sodium hydroxide solution, 26 g of 1 mol / L sodium carbonate solution, and 300 mL of deionized water, stir them evenly to obtain a mixed solution B; Take 1.2 g of walnut shell biochar and 100 mL of mixed solution A, add mixed solution B dropwise while stirring, stir for 3.5 h, heat to 86 ° C and react for 9.5 h, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex; Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise, adjust the pH to 8.5, add 10g of biochar-metal hydroxide complex, ultrasonically disperse for 35min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 15min, then stir for 12h, filter, wash, and dry to obtain a modified biochar-metal hydroxide complex; Step 3: Preparation of chitosan-acrylic acid copolymer: 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of chitosan and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain a chitosan-acrylic acid copolymer. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen and stirred for 35 min. The acrylamide solution was added dropwise and microwaved at 52°C for 13 min. The mixture was removed and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 4 parts of activated carbon, 8 parts of chitosan-acrylic acid copolymer, 9 parts of modified biochar-metal hydroxide complex, 6.5 parts of sodium lignin sulfonate, 7 parts of polyvinyl pyrrolidone, 5 parts of ethyl acetate, and 5.5 parts of anhydrous ferric chloride.

[0023] Comparative Example 3: No metal hydroxide was added for compounding, and the rest was the same as in Example 1: Step 1: Preparation of walnut shell biochar: Walnut shells were dried, crushed, and passed through a 100-mesh sieve to obtain walnut shell powder. 15 g of walnut shell powder and 400 mL of 2 M sulfuric acid were stirred for 3.5 h, reacted for 21 h, washed, dried, and then pyrolyzed at 300 ° C under nitrogen protection. 8 g of potassium hydroxide was added and pyrolyzed at 600 ° C under nitrogen protection for 5.5 h. 400 mL of 10% hydrochloric acid solution was added and soaked for 11 h. The mixture was washed and dried to obtain walnut shell biochar. Step 2: Preparation of modified biochar: Take 8g of trihydroxyaminomethane and 500mL of deionized water, stir evenly, add 0.1mol / L hydrochloric acid solution dropwise to adjust the pH to 8.5, add 10g of walnut shell biochar, ultrasonically disperse for 35min, add 3.5g of dopamine hydrochloride, ultrasonically disperse for 15min, then stir for 12h, filter, wash, and dry to obtain modified biochar; Step 3: Preparation of chitosan-acrylic acid copolymer: Take 2g of chitosan powder and 40mL of 2% acetic acid solution, heat to 71℃, stir for 2.3h to obtain chitosan solution, squeeze the chitosan solution into 80mL of 10% sodium tripolyphosphate solution and solidify for 12h, wash, add to 100mL of 5% glutaraldehyde solution, heat to 47℃ and shake for 6.5h, add 5mL of diethylenetriamine dropwise, shake for 11h, wash and dry to obtain amino chitosan microspheres; 9 g of acrylamide and 100 mL of deionized water were mixed and stirred to obtain an acrylamide solution. 1.5 g of amino-modified chitosan microspheres and 200 mL of a 0.5 wt% acrylic acid solution were mixed and stirred to obtain a chitosan-acrylic acid copolymer. 6 mL of a 4 mmol / L cerium ammonium nitrate solution was added under nitrogen protection and stirred for 35 min. The acrylamide solution was added dropwise and microwaved at 52°C for 13 min. The mixture was removed and cooled to room temperature to obtain a chitosan-acrylic acid copolymer. Step 4: Preparation of activated carbon composite polymer flocculant for water pollution: Activated carbon, chitosan-acrylic acid copolymer, modified biochar, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride are mixed and uniformly stirred to obtain an activated carbon composite polymer flocculant for water pollution; The activated carbon composite polymer flocculant for water pollution includes the following components, calculated by weight: 4 parts of activated carbon, 8 parts of chitosan-acrylic acid copolymer, 9 parts of modified biochar, 6.5 parts of sodium lignin sulfonate, 7 parts of polyvinyl pyrrolidone, 5 parts of ethyl acetate, and 5.5 parts of anhydrous ferric chloride.

[0024] experiment: 120 mg of activated carbon composite polymer flocculant for water pollution was added to 1000 g of sewage, stirred for 3 minutes, and allowed to stand for 40 minutes to obtain a treated sewage sample. The treated sewage sample was measured in mg / L. The specific results are shown in Table 1 below: Table 1

[0025] Conclusion: From the comparison of the data in the table, it can be seen that in Example 1, chitosan is not subjected to amino modification, and the compatibility between chitosan-acrylic acid copolymer and modified biochar-metal hydroxide complex is poor, and the sewage treatment performance is reduced. In Example 2, chitosan is used instead of chitosan microspheres, and the specific surface area is small, the amount of acrylic acid copolymer that can be grafted is reduced, and the performance is reduced. In Example 3, no metal hydroxide is added for compounding, the flocculation ability is reduced, the sedimentation effect of the modified biochar-metal hydroxide complex is deteriorated, and the sewage treatment performance is also reduced. The present invention performs microspheroidization on chitosan, and the specific surface area is significantly improved after microspheroidization. The amino groups, hydroxyl groups and other groups on the chitosan are retained inside the microspheres, and the amount of acrylic acid copolymer that can be grafted is increased. Heavy metal ions and soluble organic pollutants can be adsorbed, and the flocculation speed is fast.

[0026] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. An activated carbon composite polymer flocculant for water pollution, characterized by: The activated carbon composite polymer flocculant for water pollution comprises the following components, calculated by weight: 3-5 parts of activated carbon, 7-10 parts of chitosan-acrylic acid copolymer, 8-10 parts of modified biochar-metal hydroxide complex, 6-7 parts of sodium lignin sulfonate, 5-8 parts of polyvinyl pyrrolidone, 4-6 parts of ethyl acetate, and 5-6 parts of anhydrous ferric chloride.

2. The activated carbon composite polymer flocculant for water pollution according to claim 1, characterized in that: The preparation method of the modified biochar-metal hydroxide complex comprises the following steps: taking trihydroxyaminomethane and deionized water, stirring evenly, adding hydrochloric acid solution dropwise, adjusting the pH to 8.5, adding the biochar-metal hydroxide complex, ultrasonically dispersing for 30-40 minutes, adding dopamine hydrochloride, ultrasonically dispersing for 10-20 minutes, and then stirring for 10-14 hours, filtering, washing, and drying to obtain the modified biochar-metal hydroxide complex.

3. The activated carbon composite polymer flocculant for water pollution according to claim 2, characterized in that: The preparation method of the biochar-metal hydroxide composite comprises the following steps: Step 1: Take aluminum chloride hexahydrate and magnesium chloride hexahydrate, stir them evenly to obtain a mixed solution A; take sodium hydroxide solution, sodium carbonate solution, and deionized water, stir them evenly to obtain a mixed solution B; Step 2: Take walnut shell biochar and mixed solution A, add mixed solution B dropwise while stirring, stir for 3-4 hours, heat to 85-87°C and react for 9-10 hours, filter, wash, dry and grind to obtain a biochar-metal hydroxide complex.

4. The activated carbon composite polymer flocculant for water pollution according to claim 3, characterized in that: The preparation method of the walnut shell biochar comprises the following steps: taking walnut shells, drying and crushing them, and passing them through a 100-mesh sieve to obtain walnut shell powder; taking the walnut shell powder and sulfuric acid, stirring them for 3-4 hours, reacting them for 20-22 hours, washing and drying them, and then pyrolyzing them at 300°C under nitrogen protection; adding potassium hydroxide, pyrolyzing them at 600°C under nitrogen protection for 5-6 hours, adding a hydrochloric acid solution, soaking them for 10-12 hours, washing and drying them to obtain the walnut shell biochar.

5. The activated carbon composite polymer flocculant for water pollution according to claim 1, characterized in that: The preparation method of the chitosan-acrylic acid copolymer comprises the following steps: taking acrylamide and deionized water, stirring evenly to obtain an acrylamide solution; taking chitosan and acrylic acid solution, stirring evenly, adding cerium ammonium nitrate solution under nitrogen protection, stirring for 30-40 minutes, dropwise adding the acrylamide solution, reacting with a microwave at 50-55° C. for 12-15 minutes, taking out, and cooling to room temperature to obtain the chitosan-acrylic acid copolymer.

6. The activated carbon composite polymer flocculant for water pollution according to claim 5, characterized in that: The chitosan is chitosan microspheres. The preparation method of the chitosan microspheres is as follows: taking chitosan powder and acetic acid solution, heating to 70-72° C., stirring for 2-2.5 hours to obtain a chitosan solution, squeezing the chitosan solution into a sodium tripolyphosphate solution for solidification for 10-14 hours, washing, adding the chitosan solution to a glutaraldehyde solution, heating to 45-50° C. and shaking for 6-7 hours, shaking for 10-12 hours, washing, and drying to obtain amino chitosan microspheres.

7. The activated carbon composite polymer flocculant for water pollution according to claim 6, characterized in that: The chitosan microspheres are amino chitosan microspheres, and the preparation method thereof is as follows: chitosan powder and acetic acid solution are taken, heated to 70-72° C., stirred for 2-2.5 hours to obtain a chitosan solution, extruded into a sodium tripolyphosphate solution, solidified for 10-14 hours, washed, added to a glutaraldehyde solution, heated to 45-50° C., and shaken for 6-7 hours, diethylenetriamine is added dropwise, shaken for 10-12 hours, washed, and dried to obtain the amino chitosan microspheres.

8. The activated carbon composite polymer flocculant for water pollution according to claim 1, characterized in that: The preparation method of the activated carbon composite polymer flocculant for water pollution comprises the following steps: taking activated carbon, chitosan-acrylic acid copolymer, modified biochar-metal hydroxide complex, sodium lignin sulfonate, polyvinyl pyrrolidone, ethyl acetate, and anhydrous ferric chloride, stirring the mixture evenly to obtain the activated carbon composite polymer flocculant for water pollution.

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