Composite sludge dewatering agent and preparation method thereof

Abstract

This invention discloses a composite sludge dewatering agent and its preparation method. The dewatering agent is prepared by polymerizing modified monomers, a modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, and sodium methpropylene sulfonate to form polyacrylamide on the surface of the modified carrier. The surface of this dewatering agent contains both positive and negative charges. The positive charge can bind with negatively charged organic suspended matter, while the negative charge can accelerate the settling of inorganic suspended matter. The polyacrylamide on the surface contains organosilicon segments, which enhance the hydrophobic effect of the dewatering agent, achieving a water-repellent effect while adsorbing suspended matter. Furthermore, the surface contains an iron-based metal-organic framework, which, combined with the positive charge on the surface, can disrupt the stable structure of the extracellular polymeric material of the sludge, thereby dispersing organic matter and releasing internal moisture. Simultaneously, the organic matter can be encapsulated by the cyclodextrin cavities on the surface and the porous cavities inside, further improving the sludge dewatering effect.

Description

Technical Field

[0001] This invention relates to the field of sludge dewatering technology, specifically to a composite sludge dewatering agent and its preparation method. Background Technology

[0002] Sludge dewatering is the primary problem to be solved in sludge treatment. Dewatered sludge has a lower water content, resulting in a significant reduction in volume. This reduces the scale and cost of subsequent sludge transportation, composting, and landfilling, and makes further dewatering treatments such as drying and incineration more effective. However, due to the high hydrophilicity of sludge, its water content is difficult to remove directly mechanically. Sludge conditioning, i.e., pretreatment of sludge using chemical or physical methods, is an effective approach. The principle of sludge conditioning is to alter the physical and chemical properties of sludge particles. By disrupting the colloidal structure of the sludge, more bound water and free water are separated from the particles, improving dewatering performance. Chemical conditioning is simple to operate, economical, and effective, making it a commonly used method both domestically and internationally. However, existing sludge dewatering agents require large dosages and have poor dewatering effects, impacting sludge treatment efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a composite sludge dewatering agent and its preparation method, which solves the problems of the current sludge dewatering agents having general dewatering effect and large dosage.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a composite sludge dewatering agent comprises the following steps:

[0006] Step A1: Mix the composite carrier, terephthalic acid, ferric chloride hexahydrate and DMF evenly, and react for 20-25 hours at a speed of 150-200 r / min and a temperature of 80-85℃ to obtain the pretreated carrier. Mix the pretreated carrier, acryloyl chloride, triethylamine and DMF evenly, and react for 6-8 hours at a speed of 200-300 r / min and a temperature of 30-40℃ to obtain the modified carrier.

[0007] Step A2: Mix octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide evenly, purge with nitrogen, and react for 3-5 hours at a speed of 150-200 r / min and a temperature of 90-95℃ to obtain aminopolysiloxane. Mix aminopolysiloxane, epoxybutene and DMF evenly, and react for 6-8 hours at a speed of 120-150 r / min, a temperature of 30-40℃ and a pH of 11-12 to obtain modified monomer.

[0008] Step A3: Mix the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, sodium methacrylate sulfonate and DMF evenly. Stir and add ammonium persulfate and 2,2'-azo(2-methylpropylamidine) dihydrochloride at a speed of 150-200 r / min and a temperature of 20-25℃. Heat to 40-50℃ and react for 3-4 hours to obtain the composite sludge dewatering agent.

[0009] Furthermore, the mass ratio of the composite carrier, terephthalic acid, and ferric chloride hexahydrate mentioned in step A1 is 1:1:1.8, and the molar ratio of the pretreatment carrier, acryloyl chloride, and triethylamine is 1g:10mmol:10mmol.

[0010] Furthermore, in step A2, the molar ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide is 1.2:1:1.5, and the molar ratio of aminopolysiloxane and epoxybutene is 1:4.

[0011] Furthermore, in step A3, the ratio of the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, and sodium methpropylene sulfonate is 0.2 mol: 20 g: 9 mol: 1 mol: 1 mol, the amount of ammonium persulfate is 0.1% of the total mass of the modified monomer, acrylamide, acryloyloxyethyltrimethylammonium chloride, and sodium methpropylene sulfonate, and the molar ratio of 2,2'-azo(2-methylpropylamidine) dihydrochloride to ammonium persulfate is 1:1.

[0012] Furthermore, the composite carrier is prepared by the following steps:

[0013] Step B1: Mix lignin, sodium hydroxide, ethanol and deionized water evenly. Stir for 1-2 hours at 120-150 r / min and 50-60℃. Add chloroacetic acid and continue the reaction for 1-2 hours. Adjust the pH to acidic to obtain carboxylated lignin. Disperse the carboxylated lignin in toluene, add KH550 and dicyclohexylcarbodiimide, and react for 3-5 hours at 200-300 r / min and 20-25℃ to obtain modified lignin.

[0014] Step B2: Mix hexadecyltrimethylammonium bromide, deionized water, toluene, modified lignin, and tetraethyl orthosilicate. Stir for 30-40 minutes at 800-1000 r / min and 60-70℃. Then, raise the temperature to 200-210℃ and react for 3-5 hours. Filter to remove the filtrate. Add the substrate to a muffle furnace and calcine for 2-3 hours at 700-750℃ under argon protection to obtain the precursor. Disperse the precursor in ethanol and stir at 120-150 r / min and 60-70℃, adding KH550 and deionized water. React for 3-5 hours to obtain the modified precursor.

[0015] Step B3: Mix β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and DMF evenly. React at 120-150 r / min and 65-70℃ for 2-3 hours. Add sodium hydroxide solution, raise the temperature to 75-80℃, and react for 3-5 hours to obtain modified cyclodextrin. Mix the modified cyclodextrin, modified precursor, and DMF evenly. React at 200-300 r / min, 30-40℃, and pH 10-11 for 3-5 hours. Add 2-aminoterephthalic acid and continue the reaction for 3-5 hours to obtain the composite carrier.

[0016] Furthermore, the mass ratio of lignin, sodium hydroxide, and chloroacetic acid in step B1 is 5:10:3, and the molar ratio of the carboxyl group on the carboxylated lignin, KH550, and dicyclohexylcarbodiimide is 1:1:1.1.

[0017] Furthermore, in step B2, the mass ratio of hexadecyltrimethylammonium bromide, modified lignin, and tetraethyl orthosilicate is 5:3:10, and the amount of KH550 used is 1% of the precursor mass.

[0018] Furthermore, in step B3, the ratio of β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and sodium hydroxide solution is 3g:1g:0.9g:15mL, the mass fraction of sodium hydroxide solution is 25%, and the mass ratio of modified cyclodextrin, modified precursor, and 2-aminoterephthalic acid is 5:1:3.

[0019] The beneficial effects of this invention are as follows: The composite sludge dewatering agent prepared by this invention uses a composite carrier, terephthalic acid, and ferric chloride hexahydrate as raw materials. An iron-based metal-organic framework is formed on the surface of the composite carrier to obtain a pretreated carrier. The pretreated carrier is reacted with acryloyl chloride, causing the hydroxyl groups on the pretreated carrier to react with the acyl chloride on the acryloyl chloride, resulting in the grafting of double bonds on the surface of the pretreated carrier to obtain a modified carrier. Octamethylcyclotetrasiloxane is ring-opened and polymerized with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to form an amino-terminated polysiloxane, resulting in an amino polysiloxane. The amino polysiloxane is reacted with epoxide butene, causing the amino groups on the amino polysiloxane to react with the epoxy groups on the epoxide butene to obtain a modified monomer. The modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, and sodium methpropylene sulfonate are polymerized to form polyacrylamide on the surface of the modified carrier, resulting in a dewatering agent.

[0020] The composite carrier uses lignin and chloroacetic acid as raw materials. Under the action of sodium hydroxide solution, the hydroxyl groups in the lignin molecule are converted to sodium hydroxide, which then reacts with the chlorine atoms on the chloroacetic acid to produce carboxylated lignin. The carboxylated lignin and KH550 are then reacted with dicyclohexylcarbodiimide to dehydrate the carboxyl groups on the carboxylated lignin and the amino groups on the KH550, producing modified lignin. The modified lignin is then hydrothermally reacted with tetraethyl orthosilicate, followed by calcination under argon protection to transform the modified lignin into carbon nanotubes, while simultaneously coating the surface with porous carbon nanotubes. A precursor was prepared from silicon dioxide. The precursor was treated with KH550 to graft amino groups onto its surface, thus obtaining a modified precursor. β-cyclodextrin and epichlorohydrin were reacted to react the epoxy groups on epichlorohydrin with the hydroxyl groups on β-cyclodextrin. Then, a new epoxy group was formed by ring closure under the action of sodium hydroxide solution, thus obtaining a modified cyclodextrin. The modified cyclodextrin and the modified precursor were reacted to react the epoxy groups on the modified cyclodextrin with the amino groups on the modified precursor. 2-Aminoterephthalic acid was added to react with the remaining epoxy groups to obtain a composite carrier.

[0021] The dewatering agent has both positive and negative charges on its surface. The positive charge can combine with negatively charged organic suspended matter, while the negative charge can accelerate the settling of inorganic suspended matter. The polyacrylamide on the surface contains organosilicon segments, which can enhance the hydrophobic effect of the dewatering agent. It can achieve a water-blocking effect while adsorbing suspended matter. In addition, the surface contains an iron-based metal-organic framework, which, combined with the positive charge on the surface, can destroy the stable structure of the extracellular polymer of sludge, thereby dispersing organic matter and releasing internal water. At the same time, the organic matter can be covered by the cyclodextrin cavities on the surface and the porous cavities inside, which further improves the sludge dewatering effect. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0023] A method for preparing a composite sludge dewatering agent comprises the following steps:

[0024] Step A1: Mix the composite carrier, terephthalic acid, ferric chloride hexahydrate and DMF evenly, and react for 20 h at a speed of 150 r / min and a temperature of 80 °C to obtain the pretreated carrier. Mix the pretreated carrier, acryloyl chloride, triethylamine and DMF evenly, and react for 6 h at a speed of 200 r / min and a temperature of 30 °C to obtain the modified carrier.

[0025] Step A2: Octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed evenly, and nitrogen gas is introduced for protection. The mixture is reacted for 3 hours at a speed of 150 r / min and a temperature of 90 °C to obtain aminopolysiloxane. Aminopolysiloxane, epoxybutene and DMF are mixed evenly and reacted for 6 hours at a speed of 120 r / min, a temperature of 30 °C and a pH of 11-12 to obtain modified monomer.

[0026] Step A3: Mix the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, sodium methacrylate sulfonate and DMF evenly. Stir and add ammonium persulfate and 2,2'-azo(2-methylpropylamidine) dihydrochloride at 150 r / min and 20℃. Heat to 40℃ and react for 3 h to obtain the composite sludge dewatering agent.

[0027] The mass ratio of the composite carrier, terephthalic acid and ferric chloride hexahydrate mentioned in step A1 is 1:1:1.8, and the molar ratio of the pretreatment carrier, acryloyl chloride and triethylamine is 1g:10mmol:10mmol.

[0028] The molar ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide in step A2 is 1.2:1:1.5, and the molar ratio of aminopolysiloxane and epoxybutene is 1:4.

[0029] The ratio of the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate in step A3 is 0.2mol:20g:9mol:1mol:1mol. The amount of ammonium persulfate is 0.1% of the total mass of the modified monomer, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate. The molar ratio of 2,2'-azo(2-methylpropylamidine) dihydrochloride and ammonium persulfate is 1:1.

[0030] The composite carrier is prepared by the following steps:

[0031] Step B1: Mix lignin, sodium hydroxide, ethanol and deionized water evenly. Stir for 1 hour at 120 r / min and 50°C. Add chloroacetic acid and continue the reaction for 1 hour. Adjust the pH to acidic to obtain carboxylated lignin. Disperse the carboxylated lignin in toluene. Add KH550 and dicyclohexylcarbodiimide. React for 3 hours at 200 r / min and 20°C to obtain modified lignin.

[0032] Step B2: Mix hexadecyltrimethylammonium bromide, deionized water, toluene, modified lignin, and tetraethyl orthosilicate. Stir for 30 min at 800 r / min and 60 °C. Then, raise the temperature to 200 °C and react for 3 h. Filter to remove the filtrate. Add the substrate to a muffle furnace and calcine for 2 h at 700 °C under argon protection to obtain the precursor. Disperse the precursor in ethanol and stir at 120 r / min and 60 °C. Add KH550 and deionized water and react for 3 h to obtain the modified precursor.

[0033] Step B3: Mix β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and DMF evenly. React at 120 r / min and 65°C for 2 hours. Add sodium hydroxide solution, raise the temperature to 75°C, and react for 3 hours to obtain modified cyclodextrin. Mix the modified cyclodextrin, modified precursor, and DMF evenly. React at 200 r / min, 30°C, and pH 10 for 3 hours. Add 2-aminoterephthalic acid and continue the reaction for 3 hours to obtain the composite carrier.

[0034] The mass ratio of lignin, sodium hydroxide, and chloroacetic acid in step B1 is 5:10:3, and the molar ratio of carboxyl groups on carboxylated lignin, KH550, and dicyclohexylcarbodiimide is 1:1:1.1.

[0035] In step B2, the mass ratio of hexadecyltrimethylammonium bromide, modified lignin, and tetraethyl orthosilicate is 5:3:10, and the amount of KH550 used is 1% of the precursor mass.

[0036] The ratio of β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and sodium hydroxide solution in step B3 is 3g:1g:0.9g:15mL, the mass fraction of sodium hydroxide solution is 25%, and the mass ratio of modified cyclodextrin, modified precursor, and 2-aminoterephthalic acid is 5:1:3. Example

[0037] A method for preparing a composite sludge dewatering agent comprises the following steps:

[0038] Step A1: Mix the composite carrier, terephthalic acid, ferric chloride hexahydrate and DMF evenly, and react for 23 h at a speed of 150 r / min and a temperature of 85℃ to obtain the pretreated carrier. Mix the pretreated carrier, acryloyl chloride, triethylamine and DMF evenly, and react for 7 h at a speed of 200 r / min and a temperature of 35℃ to obtain the modified carrier.

[0039] Step A2: Octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed evenly, and nitrogen gas is introduced for protection. The mixture is reacted for 4 hours at a speed of 150 r / min and a temperature of 90 °C to obtain aminopolysiloxane. Aminopolysiloxane, epoxybutene and DMF are mixed evenly and reacted for 7 hours at a speed of 120 r / min, a temperature of 35 °C and a pH of 11 to obtain modified monomer.

[0040] Step A3: Mix the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, sodium methacrylate sulfonate and DMF evenly. Stir and add ammonium persulfate and 2,2'-azo(2-methylpropylamidine) dihydrochloride at 150 r / min and 23℃. Heat to 45℃ and react for 3.5 h to obtain the composite sludge dewatering agent.

[0041] The mass ratio of the composite carrier, terephthalic acid and ferric chloride hexahydrate mentioned in step A1 is 1:1:1.8, and the molar ratio of the pretreatment carrier, acryloyl chloride and triethylamine is 1g:10mmol:10mmol.

[0042] The molar ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide in step A2 is 1.2:1:1.5, and the molar ratio of aminopolysiloxane and epoxybutene is 1:4.

[0043] The ratio of the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate in step A3 is 0.2mol:20g:9mol:1mol:1mol. The amount of ammonium persulfate is 0.1% of the total mass of the modified monomer, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate. The molar ratio of 2,2'-azo(2-methylpropylamidine) dihydrochloride and ammonium persulfate is 1:1.

[0044] The composite carrier is prepared by the following steps:

[0045] Step B1: Mix lignin, sodium hydroxide, ethanol and deionized water evenly. Stir for 1.5 h at 120 r / min and 55 °C. Add chloroacetic acid and continue the reaction for 1.5 h. Adjust the pH to acidic to obtain carboxylated lignin. Disperse the carboxylated lignin in toluene. Add KH550 and dicyclohexylcarbodiimide. React for 45 h at 200 r / min and 20 °C to obtain modified lignin.

[0046] Step B2: Cetyltrimethylammonium bromide, deionized water, toluene, modified lignin, and tetraethyl orthosilicate were mixed and stirred for 35 min at 800 r / min and 65 °C. The mixture was then heated to 205 °C and reacted for 4 h. The filtrate was removed by filtration, and the substrate was added to a muffle furnace and calcined for 2.5 h at 730 °C under argon protection to obtain the precursor. The precursor was dispersed in ethanol and stirred at 120 r / min and 65 °C. KH550 and deionized water were added and the mixture was reacted for 4 h to obtain the modified precursor.

[0047] Step B3: Mix β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and DMF evenly. React at 120 r / min and 68°C for 2.5 h. Add sodium hydroxide solution, raise the temperature to 78°C, and react for 4 h to obtain modified cyclodextrin. Mix the modified cyclodextrin, modified precursor, and DMF evenly. React at 200 r / min, 35°C, and pH 11 for 4 h. Add 2-aminoterephthalic acid and continue the reaction for 4 h to obtain the composite carrier.

[0048] The mass ratio of lignin, sodium hydroxide, and chloroacetic acid in step B1 is 5:10:3, and the molar ratio of carboxyl groups on carboxylated lignin, KH550, and dicyclohexylcarbodiimide is 1:1:1.1.

[0049] In step B2, the mass ratio of hexadecyltrimethylammonium bromide, modified lignin, and tetraethyl orthosilicate is 5:3:10, and the amount of KH550 used is 1% of the precursor mass.

[0050] The ratio of β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and sodium hydroxide solution in step B3 is 3g:1g:0.9g:15mL, the mass fraction of sodium hydroxide solution is 25%, and the mass ratio of modified cyclodextrin, modified precursor, and 2-aminoterephthalic acid is 5:1:3. Example

[0051] A method for preparing a composite sludge dewatering agent comprises the following steps:

[0052] Step A1: Mix the composite carrier, terephthalic acid, ferric chloride hexahydrate and DMF evenly, and react for 25 h at a speed of 200 r / min and a temperature of 85 °C to obtain the pretreated carrier. Mix the pretreated carrier, acryloyl chloride, triethylamine and DMF evenly, and react for 8 h at a speed of 300 r / min and a temperature of 40 °C to obtain the modified carrier.

[0053] Step A2: Octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed evenly, and nitrogen gas is introduced for protection. The mixture is reacted for 5 hours at a speed of 200 r / min and a temperature of 95 °C to obtain aminopolysiloxane. Aminopolysiloxane, epoxybutene and DMF are mixed evenly and reacted for 8 hours at a speed of 150 r / min, a temperature of 40 °C and a pH of 12 to obtain modified monomer.

[0054] Step A3: Mix the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, sodium methacrylate sulfonate and DMF evenly. Stir and add ammonium persulfate and 2,2'-azo(2-methylpropylamidine) dihydrochloride at 200 r / min and 25℃. Heat to 50℃ and react for 4 h to obtain the composite sludge dewatering agent.

[0055] The mass ratio of the composite carrier, terephthalic acid and ferric chloride hexahydrate mentioned in step A1 is 1:1:1.8, and the molar ratio of the pretreatment carrier, acryloyl chloride and triethylamine is 1g:10mmol:10mmol.

[0056] The molar ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide in step A2 is 1.2:1:1.5, and the molar ratio of aminopolysiloxane and epoxybutene is 1:4.

[0057] The ratio of the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate in step A3 is 0.2mol:20g:9mol:1mol:1mol. The amount of ammonium persulfate is 0.1% of the total mass of the modified monomer, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methpropylene sulfonate. The molar ratio of 2,2'-azo(2-methylpropylamidine) dihydrochloride and ammonium persulfate is 1:1.

[0058] The composite carrier is prepared by the following steps:

[0059] Step B1: Mix lignin, sodium hydroxide, ethanol and deionized water evenly. Stir for 2 hours at 150 r / min and 60°C. Add chloroacetic acid and continue the reaction for 2 hours. Adjust the pH to acidic to obtain carboxylated lignin. Disperse the carboxylated lignin in toluene. Add KH550 and dicyclohexylcarbodiimide. React for 5 hours at 300 r / min and 25°C to obtain modified lignin.

[0060] Step B2: Mix hexadecyltrimethylammonium bromide, deionized water, toluene, modified lignin, and tetraethyl orthosilicate. Stir for 40 min at 1000 r / min and 70 °C. Then, raise the temperature to 210 °C and react for 5 h. Filter to remove the filtrate. Add the substrate to a muffle furnace and calcine for 3 h at 750 °C under argon protection to obtain the precursor. Disperse the precursor in ethanol and stir at 150 r / min and 70 °C. Add KH550 and deionized water and react for 5 h to obtain the modified precursor.

[0061] Step B3: Mix β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and DMF evenly. React at 150 r / min and 70°C for 3 hours. Add sodium hydroxide solution, raise the temperature to 80°C, and react for 5 hours to obtain modified cyclodextrin. Mix the modified cyclodextrin, modified precursor, and DMF evenly. React at 300 r / min, 40°C, and pH 1 for 5 hours. Add 2-aminoterephthalic acid and continue the reaction for 5 hours to obtain the composite carrier.

[0062] The mass ratio of lignin, sodium hydroxide, and chloroacetic acid in step B1 is 5:10:3, and the molar ratio of carboxyl groups on carboxylated lignin, KH550, and dicyclohexylcarbodiimide is 1:1:1.1.

[0063] In step B2, the mass ratio of hexadecyltrimethylammonium bromide, modified lignin, and tetraethyl orthosilicate is 5:3:10, and the amount of KH550 used is 1% of the precursor mass.

[0064] The ratio of β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and sodium hydroxide solution in step B3 is 3g:1g:0.9g:15mL, the mass fraction of sodium hydroxide solution is 25%, and the mass ratio of modified cyclodextrin, modified precursor, and 2-aminoterephthalic acid is 5:1:3.

[0065] Comparative Example 1

[0066] Compared with Example 1, this comparative example uses a composite carrier instead of the pretreatment carrier, but the other steps are the same.

[0067] Comparative Example 2

[0068] This comparative example did not include any modified monomers compared to Example 1, but the remaining steps were the same.

[0069] Comparative Example 3

[0070] This comparative example did not include a modified carrier compared to Example 1, but the remaining steps were the same.

[0071] Comparative Example 4

[0072] This comparative example did not include a composite carrier compared to Example 1, but the remaining steps were the same.

[0073] Comparative Example 5

[0074] Compared with Example 1, this comparative example uses a modified precursor instead of a modified carrier, but the other steps are the same.

[0075] Take 100g of sludge with a water content of 97.8%, pH of 6.8, Zeta potential of -23.7mv, and organic matter content of 43.6%. Add the sludge dewatering agents prepared in Examples 1-3 and Comparative Examples 1-5 respectively. The dosage of the sludge dewatering agent is 10mg / g. Stir at 400r / min for 30s, and then stir at 150r / min for 5min. Measure the sludge specific resistance and sludge cake moisture content. The test results are shown in the table below.

[0076]

[0077] As shown in the table above, this application has a very good sludge dewatering effect.

[0078] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a composite sludge dewatering agent, characterized in that: It is made by the following steps: Step A1: Mix and react the composite carrier, terephthalic acid, ferric chloride hexahydrate and DMF to obtain a pretreated carrier. Mix and react the pretreated carrier, acryloyl chloride, triethylamine and DMF to obtain a modified carrier. Step A2: Mix octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide to prepare aminopolysiloxane; mix aminopolysiloxane, epoxybutene and DMF to prepare modified monomer. Step A3: Mix and stir the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride, sodium methallyl sulfonate and DMF, add ammonium persulfate and 2,2'-azo(2-methylpropylamidine) dihydrochloride, heat and react to obtain the composite sludge dewatering agent; The composite carrier is prepared by the following steps: Step B1: After mixing and stirring lignin, sodium hydroxide, ethanol and deionized water, chloroacetic acid is added and the reaction continues to obtain carboxylated lignin. The carboxylated lignin is dispersed in toluene, KH550 and dicyclohexylcarbodiimide are added and reacted to obtain modified lignin. Step B2: Mix and stir hexadecyltrimethylammonium bromide, deionized water, toluene, modified lignin and tetraethyl orthosilicate, heat and react, filter to remove the filtrate, add the substrate to a muffle furnace and calcine to obtain the precursor, disperse the precursor in ethanol and stir, add KH550 and deionized water, and react to obtain the modified precursor. Step B3: After mixing and reacting β-cyclodextrin, epichlorohydrin, boron trifluoride ether and DMF, sodium hydroxide solution is added and the reaction is heated to obtain modified cyclodextrin. After mixing and reacting the modified cyclodextrin, modified precursor and DMF, 2-aminoterephthalic acid is added and the reaction is continued to obtain composite carrier.

2. The preparation method of the composite sludge dewatering agent according to claim 1, characterized in that: The mass ratio of the composite carrier, terephthalic acid and ferric chloride hexahydrate mentioned in step A1 is 1:1:1.8, and the molar ratio of the pretreatment carrier, acryloyl chloride and triethylamine is 1g:10mmol:10mmol.

3. The preparation method of the composite sludge dewatering agent according to claim 1, characterized in that: The molar ratio of octamethylcyclotetrasiloxane, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and tetramethylammonium hydroxide in step A2 is 1.2:1:1.5, and the molar ratio of aminopolysiloxane and epoxybutene is 1:

4.

4. The preparation method of the composite sludge dewatering agent according to claim 1, characterized in that: The ratio of the modified monomer, modified carrier, acrylamide, acryloyloxyethyltrimethylammonium chloride and sodium methacrylate sulfonate used in step A3 is 0.2 mol: 20 g: 9 mol: 1 mol: 1 mol.

5. The preparation method of the composite sludge dewatering agent according to claim 1, characterized in that: The mass ratio of lignin, sodium hydroxide, and chloroacetic acid in step B1 is 5:10:3, and the molar ratio of carboxyl groups on carboxylated lignin, KH550, and dicyclohexylcarbodiimide is 1:1:1.

1.

6. The method for preparing a composite sludge dewatering agent according to claim 1, characterized in that: In step B2, the mass ratio of hexadecyltrimethylammonium bromide, modified lignin, and tetraethyl orthosilicate is 5:3:10, and the amount of KH550 used is 1% of the precursor mass.

7. The preparation method of the composite sludge dewatering agent according to claim 1, characterized in that: The ratio of β-cyclodextrin, epichlorohydrin, boron trifluoride ether, and sodium hydroxide solution in step B3 is 3g:1g:0.9g:15mL, and the mass ratio of modified cyclodextrin, modified precursor, and 2-aminoterephthalic acid is 5:1:

3.

8. A composite sludge dewatering agent, characterized in that: It is prepared by the preparation method according to any one of claims 1-7.

Images