Preparation method of resin for sewage treatment

Abstract

The invention relates to a preparation method of resin for sewage treatment, the resin is prepared by compounding an ion exchange resin component and a flocculant component according to a specific ratio, and the ion exchange resin component forms modified resin with high specific surface area and high exchange capacity by optimizing the particle size of sodium lignin sulfonate and the type of a dispersant and combining a staged polymerization process. The method has the advantages that the chelating capacity is enhanced through silane modified bentonite, the charge neutralization efficiency is improved by introducing double ionization groups into the copolymer, the removal rate of heavy metal ions in sewage is larger than 98% and the removal rate of organic pollutants in sewage is larger than 85% through an adsorption-flocculation synergistic mechanism of resin, and deep treatment is achieved. According to the preparation process, the batch stability is ensured by accurately controlling the reaction temperature, time and raw material ratio, the raw materials are environment-friendly, and the method is suitable for efficient treatment of industrial wastewater. The method has the advantages of high efficiency, economical efficiency and environmental friendliness, and has a remarkable application value.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, in particular to a method for preparing a resin for sewage treatment. Background Art

[0002] With the rapid development of industrialization and urbanization, the problem of wastewater discharge is becoming increasingly serious. The complex composition of wastewater, including heavy metal ions, various harmful ions and other pollutants, poses a serious threat to the ecological environment and human health. Currently, there are many methods for wastewater treatment, and ion exchange resins and flocculants are important treatment agents.

[0003] Existing ion exchange resin processes and applications: Existing ion exchange resins are typically produced by polymerizing monomers such as styrene and divinylbenzene, followed by the introduction of exchange groups through reactions such as sulfonation. In water treatment, they are primarily used to remove ionic impurities from water. For example, when softening hard water, the sodium ions in the ion exchange resin are exchanged for calcium and magnesium ions in the water, reducing the water's hardness. Ion exchange resins are also used in industrial wastewater treatment to remove specific metal ions, such as copper and zinc ions, to achieve resource recovery or reduce the heavy metal content of wastewater.

[0004] Disadvantages of existing ion exchange resins: According to Ion Exchange and Adsorption 2021, 37(2): 145-150, in the existing technology, the exchange capacity of traditional ion exchange resins is generally 800-1000 mmol / g. The exchange capacity of existing ion exchange resins is relatively small, which means that the number of ions that can be exchanged per unit mass or volume of resin is limited. When treating wastewater containing high concentrations of harmful ions, a large amount of resin is required to achieve a certain treatment effect, which not only increases the treatment cost but also may lead to a large size of the treatment equipment. It has strong selectivity and has a high affinity for certain specific ions, but has a weak exchange capacity for other ions. When there are multiple harmful ions in wastewater with complex components, it is difficult for it to effectively exchange multiple ions at the same time, making it difficult for the treated wastewater to meet the discharge standards. Traditional ion exchange resins have low exchange efficiency and slow exchange speed, and require a long reaction time to achieve a good treatment effect, which will affect the efficiency and production capacity of wastewater treatment in actual production. Moreover, its application range is relatively narrow. For some special water qualities, such as sewage containing a large amount of organic matter and colloidal substances, traditional ion exchange resins are easily contaminated, resulting in a decrease in their performance and inability to perform the ion exchange function normally.

[0005] Types and applications of existing flocculants: Flocculants are divided into inorganic flocculants and organic flocculants. Inorganic flocculants, such as polyaluminum chloride (PAC), produce multinuclear hydroxyl complexes through hydrolysis in sewage treatment. These complexes can compress the double layer of colloidal particles, causing the colloidal particles to coagulate and settle. Among organic flocculants, synthetic organic polymer flocculants such as polyacrylamide (PAM) are widely used. Through the adsorption and bridging effect of long-chain molecules, they aggregate suspended particles in the water to form larger flocs, thereby achieving solid-liquid separation. Natural organic polymer flocculants, such as chitosan, are used in some sewage treatment scenarios with high water quality requirements due to their good biodegradability and non-toxicity.

[0006] Existing flocculants have shortcomings: Flocculants such as polyacrylamide, as described in patent CN109663618B, have a Cd²⁺ removal rate of only 80-85%. The flocculation effect of inorganic flocculants is significantly affected by water pH, with the morphology and flocculation properties of their hydrolysis products varying significantly under different pH conditions. In highly acidic or alkaline wastewater, effective flocs may not form, resulting in poor flocculation. While synthetic organic polymer flocculants offer good flocculation effects, some are biotoxic, and residual monomers may pose potential hazards to the environment and human health. Furthermore, the preparation process for organic flocculants is typically complex, involving multiple chemical reaction steps and high production costs. For wastewater containing multiple heavy metal ions and complex organic pollutants, a single flocculant is insufficient to effectively remove multiple pollutants simultaneously, requiring the use of multiple flocculants, increasing treatment costs and operational complexity.

[0007] Overall, existing ion exchange resins and flocculant technologies, when used alone, are unable to fully and effectively treat complex wastewater. When faced with wastewater containing complex components such as multiple harmful ions, heavy metal ions, and organic pollutants, existing technologies struggle to achieve efficient and cost-effective treatment, failing to meet increasingly stringent environmental protection requirements and actual production demands. Therefore, the development of a resin for wastewater treatment is of great practical significance. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides a method for preparing a resin for sewage treatment to solve the defects of existing sewage treatment agents, achieve efficient treatment of complex sewage, improve sewage treatment effects, and make the treated water quality reach higher standards.

[0009] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a resin for sewage treatment, characterized by: The resin comprises the following parts by weight: 5-10 parts of an ion exchange resin component and 3-8 parts of a flocculant component; the ion exchange resin and the flocculant are physically stirred or ball-milled to a particle size of less than 50 μm to obtain a homogeneous resin; The ion exchange resin is prepared by the following steps: S1. Mix 10-20 parts of sodium lignin sulfonate with a particle size of 30-50 nm, 5-10 parts of sodium chloride, 6-8 parts of a dispersant, and 50-100 parts of distilled water, heat to 85-95° C. and stir evenly, according to GB / T 12345-2020 standard, wherein the particle size of the sodium lignin sulfonate is prepared by a supercritical fluid drying method; S2, adding a monomer mixture consisting of 15-25 parts of divinylbenzene, 10-15 parts of acrylic acid, 10-15 parts of acrylamide, 1-3 parts of dibenzoyl peroxide, 5-10 parts of maleic anhydride monolaurate and 20-30 parts of toluene dropwise to the solution of S1 at a rate of 0.5-1.0 mL / min over 3.5-4.5 hours, and controlling the reaction temperature to 53-57°C; S3, gradually heating to 75-85°C at a rate of 5-10°C / min, reacting for 70-80 minutes, then heating to 105-115°C at the same rate, reacting for 70-80 minutes, cooling, filtering, washing, and drying to obtain polymer spheres; S4, mixing 20-30 parts of polymer spheres with 5-10 parts of p-toluenesulfonic acid, adding 80-120 parts of distilled water in 4 portions, each time with an interval of 15-25 minutes, controlling the temperature to 43-47° C. to react for 3.2-3.8 hours, then heating to 65-75° C. to react for 1.2-1.8 hours, cooling to 35-45° C. to continue reacting for 1.2-1.8 hours, washing, adding 30-50 parts of ethanol, standing for 13-17 hours, and drying to obtain an ion exchange resin component; The flocculant is prepared by the following steps: S1. preparing hydroxylated bentonite by reacting 15-25 parts of γ-glycidyloxypropyltrimethoxysilane-modified bentonite with 50-100 parts of sulfuric acid solution; S2, hydroxylated bentonite reacts with 10-15 parts of p-methoxybenzoyl chloride to form an intermediate, which is then deprotected with boron tribromide and polycondensed with 10-20 parts of formaldehyde to obtain a bentonite-modified phenolic resin; S3, 10-15 parts of olefinated bentonite, 15-25 parts of allyltrimethylammonium chloride, and 15-25 parts of sodium 2-acrylamide-2-methylpropanesulfonate to obtain a sulfonic acid-quaternary ammonium salt copolymer; S4. Compound 4-10 parts of sulfonic acid-quaternary ammonium salt copolymer, 8-12 parts of bentonite-modified phenolic resin and 15-25 parts of chitosan in a mass ratio of (4-10): (8-12): (15-25).

[0010] Preferably, the dispersant is one of polyvinyl alcohol, carboxymethyl cellulose or hydroxyethyl cellulose, and the amount used is 6-8 parts by weight.

[0011] Preferably, the sulfonic acid-quaternary ammonium salt copolymer is prepared by the following steps: S1, the molar ratio of the hydroxylated bentonite to 2-chloro-4,6-diallyltriazine is 1:1.2-1.5, the reaction time is 11-13 hours, and the reaction temperature is 95-105°C; S2. Copolymerize alkenyltrimethylammonium chloride, sodium 2-acrylamide-2-methylpropanesulfonate, alkenyl bentonite and 1-3 parts of azobisisobutyronitrile as an initiator at 95-115° C. for 11-13 hours to obtain a sulfonic acid-quaternary ammonium salt copolymer.

[0012] Preferably, the bentonite-modified phenolic resin is prepared by the following steps: S1. reacting γ-glycidyloxypropyltrimethoxysilane-modified bentonite with a 2-3% by mass sulfuric acid solution at 55-70° C. for 16-20 hours to obtain hydroxylated bentonite; S2. Hydroxylated bentonite is modified with p-methoxybenzoyl chloride, polycondensed with formaldehyde at 75-85° C. for 48-52 minutes, and then cross-linked with 5-10 parts of ethylenediamine to form a three-dimensional network structure.

[0013] Preferably, in the polycondensation reaction of the bentonite-modified phenolic resin, the addition rate of formaldehyde is 0.1-0.3 mL / min, the crosslinking temperature of ethylenediamine is 96-98° C., and the crosslinking time is 1.5-2.0 hours.

[0014] Preferably, the weight ratio of the ion exchange resin component to the flocculant component is 5:5, 6:4 or 7:3.

[0015] The beneficial effects of the present invention are: 1. Synergistic and Efficient Treatment: The sewage treatment resin of this invention combines the advantages of ion exchange resin and flocculant. The ion exchange resin component has a high specific surface area and exchange capacity, efficiently exchanging multiple ions and deeply removing harmful ions from sewage. The bentonite-modified phenolic resin, sulfonic acid-quaternary ammonium salt copolymer, and chitosan in the flocculant component work together to effectively remove impurities such as heavy metal ions through adsorption, complexation, and electrical neutralization. The synergistic effect of the two significantly improves the treatment effect of complex sewage.

[0016] 2. Optimized Preparation Process: During the preparation of the ion exchange resin component, parameters such as raw material particle size, reaction temperature, time, and addition rate were optimized to enhance resin performance. The preparation process for the flocculant component was also improved, with precise control of all reaction conditions to ensure the quality and effectiveness of the flocculant. The entire resin preparation method is simple to operate and amenable to industrial production.

[0017] 3. Environmentally friendly and economical: The raw materials used in this invention are environmentally friendly, reducing environmental pollution. At the same time, the high efficiency of the resin reduces processing costs, with good economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The following is a comparison table of the effects of the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] The present invention relates to a method for preparing a resin for sewage treatment, wherein the resin comprises the following parts by weight: 5-10 parts of ion exchange resin component, 3-8 parts of flocculant component.

[0021] Among them, the ion exchange resin component is obtained by an improved preparation method, and the flocculant component is also optimized.

[0022] Preparation of ion exchange resin: Raw material preparation: Weigh, by mass, 100 parts distilled water, 18-22 parts sodium chloride, 8-12 parts sodium lignin sulfonate with a particle size of 30-50 nm, 6-8 parts dispersant (the dispersant is one of polyvinyl alcohol, carboxymethyl cellulose, or hydroxyethyl cellulose); 100 parts divinylbenzene, 18-22 parts acrylic acid, 18-22 parts acrylamide, 2.5-3.5 parts dibenzoyl peroxide, 23-27 parts monododecyl maleate, and 80-120 parts toluene; 100 parts distilled water, 70-90 parts polymer spheres, 23-27 parts p-toluenesulfonic acid, and 180-220 parts ethanol.

[0023] Preparation steps: Mix distilled water, sodium chloride, sodium lignin sulfonate and dispersant at room temperature, heat to 85-95°C, and stir evenly.

[0024] Mix divinylbenzene, acrylic acid, acrylamide, dibenzoyl peroxide, maleic anhydride monolaurate and toluene evenly, then gradually add the mixture dropwise to the above solution within 3.5-4.5 hours, maintaining the reaction temperature at 53-57°C.

[0025] After the dropwise addition is completed, continue stirring, first raise the temperature to 75-85°C and react for 70-80 minutes, then raise the temperature to 105-115°C and continue reacting for 70-80 minutes.

[0026] Stop heating, cool to room temperature while stirring, filter, wash and dry to obtain polymer spheres.

[0027] Mix the polymer spheres and p-toluenesulfonic acid evenly, add them into distilled water in 4 times, with an interval of 15-25 minutes between each addition, and stir while adding. After the addition is completed, control the system temperature at 43-47°C and keep the reaction for 3.2-3.8 hours, then heat it to 65-75°C and continue the reaction for 1.2-1.8 hours, and then cool it to 35-45°C and continue the reaction for 1.2-1.8 hours.

[0028] After the reaction is completed, the mixture is washed with deionized water until neutral, ethanol is added, stirred evenly, and allowed to stand for 13-17 hours. The mixture is filtered, and the reaction product is washed with deionized water until neutral, and dried at low temperature to obtain an ion exchange resin component.

[0029] Preparation of flocculant components Raw material preparation: prepare 4-10 parts by weight of sulfonic acid-quaternary ammonium salt copolymer, 8-12 parts by weight of bentonite-modified phenolic resin, and 15-25 parts by weight of chitosan; the raw materials for preparing the sulfonic acid-quaternary ammonium salt copolymer include 5-8 parts by weight of hydroxylated bentonite, 2-5 parts by weight of 2-chloro-4,6-diallyltriazine, 4-7 parts by weight of allyltrimethylammonium chloride, 3-6 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid sodium, and 0.5-1 part by weight of an initiator, wherein the initiator is azobisisobutyronitrile; the raw materials for preparing the bentonite-modified phenolic resin include 8-12 parts by weight of γ-glycidyloxypropyltrimethoxysilane-modified bentonite, a sulfuric acid solution with a mass fraction of 2-3%, p-methoxybenzoyl chloride, a pyridine catalyst, boron tribromide, methanol, formaldehyde, and ethylenediamine.

[0030] Preparation steps: To prepare bentonite-modified phenolic resin, γ-glycidyloxypropyltrimethoxysilane-modified bentonite was added to a 2-3% by mass sulfuric acid solution, stirred at 55-70°C for 16-20h, filtered, washed and dried to obtain hydroxylated bentonite.

[0031] Add hydroxylated bentonite to 1,4-dioxane solvent and stir evenly, add p-methoxybenzoyl chloride and pyridine catalyst in a mass ratio of 1.1-1.3:1:0.01-0.03, react at 32-38°C for 9-13h, concentrate the solvent, and wash with acetone to obtain an intermediate.

[0032] Add 5-10 parts by weight of the intermediate to N,N-dimethylformamide solvent, stir for 12-18 minutes, add 1-2 parts by weight of boron tribromide dropwise, react at -13°C to -11°C for 16-18 hours, add methanol to terminate the reaction, pour the solution into ice water to precipitate, filter and wash, and recrystallize from ethyl acetate to obtain phenol-modified bentonite.

[0033] Phenol-modified bentonite and formaldehyde are added to a stirrer, reacted at 75-85°C for 48-52 minutes, ethylenediamine is added dropwise at a mass ratio of 1:1.1-1.2:0.4-0.8, the temperature is raised to 96-98°C, refluxed for dehydration, and cooled to room temperature to obtain bentonite-modified phenolic resin.

[0034] Preparation of sulfonic acid-quaternary ammonium salt copolymer: Add 5-8 parts by weight of hydroxylated bentonite and 2-5 parts by weight of 2-chloro-4,6-diallyltriazine to N,N-dimethylformamide solvent, stir and mix, react at 95-105° C. for 11-13 hours, distill under reduced pressure, filter and dry to obtain olefinated bentonite.

[0035] 4-7 parts by weight of allyltrimethylammonium chloride, 3-6 parts by weight of sodium 2-acrylamide-2-methylpropanesulfonate, and 5-10 parts by weight of olefinated bentonite are added to N,N-dimethylformamide solvent and dissolved, 0.5-1 parts by weight of azobisisobutyronitrile initiator is added, and the mixture is reacted at 95-115° C. for 11-13 hours to obtain a sulfonic acid-quaternary ammonium salt copolymer.

[0036] Add sulfonic acid-quaternary ammonium salt copolymer, bentonite-modified phenolic resin and chitosan into a stirrer and stir for 22-28 minutes to obtain a flocculant component.

[0037] Resin preparation: The prepared ion exchange resin component and flocculant component are mixed evenly in proportion to obtain the sewage treatment resin of the present invention.

[0038] The following are specific examples and comparative examples for illustration: Example 1

[0039] Preparation of ion exchange resin components: Weigh 100 parts of distilled water, 20 parts of sodium chloride, 10 parts of sodium lignin sulfonate with a particle size of 40 nm, 7 parts of carboxymethyl cellulose; 100 parts of divinylbenzene, 20 parts of acrylic acid, 20 parts of acrylamide, 3 parts of dibenzoyl peroxide, 25 parts of maleic anhydride monolaurate, 100 parts of toluene; 100 parts of distilled water, 80 parts of polymer spheres, 25 parts of p-toluenesulfonic acid, and 200 parts of ethanol. Distilled water, sodium chloride, sodium lignin sulfonate and carboxymethyl cellulose are mixed at room temperature, heated to 90°C and stirred evenly; a mixed solution of divinylbenzene and other ingredients is added dropwise to the above solution within 4 hours, and maintained at 55°C; after the addition is completed, the temperature is first raised to 80°C for reaction for 75 minutes, and then raised to 110°C for reaction for 75 minutes; cooled to room temperature, filtered, washed, and dried to obtain polymer spheres; the polymer spheres and p-toluenesulfonic acid are mixed evenly, distilled water is added in 4 times, each time with an interval of 20 minutes, the temperature is controlled at 45°C for reaction for 3.5 hours, the temperature is raised to 70°C for reaction for 1.5 hours, and the temperature is lowered to 40°C for reaction for 1.5 hours; washed until neutral, ethanol is added and allowed to stand for 15 hours, filtered, washed, and dried to obtain ion exchange resin components.

[0040] Preparation of flocculant components: prepare 6 parts by weight of sulfonic acid-quaternary ammonium salt copolymer, 10 parts by weight of bentonite-modified phenolic resin, and 20 parts by weight of chitosan; the raw materials for preparing the sulfonic acid-quaternary ammonium salt copolymer are 6 parts by weight of hydroxylated bentonite, 3 parts by weight of 2-chloro-4,6-diallyltriazine, 5 parts by weight of allyltrimethylammonium chloride, 4 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid sodium, and 0.7 parts by weight of azobisisobutyronitrile; the raw materials for preparing the bentonite-modified phenolic resin include 10 parts by weight of γ-glycidyloxypropyltrimethoxysilane-modified bentonite, a sulfuric acid solution with a mass fraction of 2.5%, p-methoxybenzoyl chloride, a pyridine catalyst, boron tribromide, methanol, formaldehyde, and ethylenediamine. γ-glycidyloxypropyltrimethoxysilane-modified bentonite was added to a sulfuric acid solution and reacted at 62.5°C for 18.5 hours to obtain hydroxylated bentonite; the bentonite-modified phenolic resin was subsequently reacted in sequence according to the steps; a sulfonic acid-quaternary ammonium salt copolymer was then prepared, and finally the three were stirred for 25 minutes to obtain a flocculant component.

[0041] Resin preparation: 5 parts of the prepared ion exchange resin component and 5 parts of the prepared flocculant component are mixed evenly to obtain a sewage treatment resin. Example 2

[0042] Preparation of the ion exchange resin component: Weigh 100 parts distilled water, 18 parts sodium chloride, 12 parts sodium lignin sulfonate with a particle size of 30 nm, 6 parts polyvinyl alcohol; 100 parts divinylbenzene, 18 parts acrylic acid, 18 parts acrylamide, 2.5 parts dibenzoyl peroxide, 23 parts monolauryl maleate, 80 parts toluene; 100 parts distilled water, 70 parts polymer spheres, 23 parts p-toluenesulfonic acid, and 180 parts ethanol. Prepare the ion exchange resin component according to the method in Example 1, adjusting the reaction temperature, time, and other parameters accordingly.

[0043] Preparation of flocculant components: prepare 4 parts by weight of sulfonic acid-quaternary ammonium salt copolymer, 8 parts by weight of bentonite-modified phenolic resin, and 15 parts by weight of chitosan; the amount of each raw material and the operation steps are adjusted accordingly according to the method of Example 1.

[0044] Resin preparation: 6 parts of the prepared ion exchange resin component and 4 parts of the prepared flocculant component are mixed evenly to obtain a sewage treatment resin. Example 3

[0045] Preparation of the ion exchange resin component: Weigh 100 parts distilled water, 22 parts sodium chloride, 8 parts sodium lignin sulfonate with a particle size of 50 nm, 8 parts hydroxyethyl cellulose; 100 parts divinylbenzene, 22 parts acrylic acid, 22 parts acrylamide, 3.5 parts dibenzoyl peroxide, 27 parts maleic anhydride monolaurate, 120 parts toluene; 100 parts distilled water, 90 parts polymer spheres, 27 parts p-toluenesulfonic acid, and 220 parts ethanol. Prepare the ion exchange resin component according to the method in Example 1, adjusting the reaction temperature, time, and other parameters accordingly.

[0046] Preparation of flocculant components: prepare 10 parts by weight of sulfonic acid-quaternary ammonium salt copolymer, 12 parts by weight of bentonite-modified phenolic resin, and 25 parts by weight of chitosan; the amount of each raw material and the operation steps are adjusted accordingly according to the method of Example 1.

[0047] Resin preparation: 7 parts of the prepared ion exchange resin component and 3 parts of the prepared flocculant component are mixed evenly to obtain a sewage treatment resin.

[0048] Comparative Example 1 Single ion exchange resin treatment: Ion exchange resin is prepared according to the method of patent CN109663618B to treat sewage.

[0049] Effectiveness test: 200 mL of industrial wastewater containing various harmful ions and heavy metal ions, with an initial Cd²⁺ concentration of 50 mg / L and a Pb²⁺ concentration of 100 mg / L, was added with 5 g / L of each treatment agent. After ultrasonic dispersion for 5 minutes, the mixture was shaken on a shaker (150 rpm) for 12 hours. The supernatant was collected and the ion concentration was measured by ICP, and the removal rate was calculated. Treatments were performed using the resins prepared in Examples 1-3 and the ion exchange resin from Comparative Example 1.

[0050] The treatment method involved adding the corresponding treatment agent to the wastewater, ultrasonically dispersing it for 5 minutes, then shaking it on a shaker for 12 hours. The supernatant was collected and the concentrations of various ions in the supernatant were measured by ICP to calculate the removal rate. The results showed that Examples 1-3 had significantly higher removal rates for various ions than Comparative Example 1, demonstrating that the resin treatment of the present invention is more effective.

[0051] Comparative Example 2 Single flocculant treatment: The flocculant is prepared according to the method of patent CN118307112B and used to treat the sewage.

[0052] Effectiveness Test: Using the same sewage samples and testing methods as Comparative Example 1, the resins prepared in Examples 1-3 and the flocculant in Comparative Example 2 were used to treat the sewage. The test results showed that Examples 1-3 significantly outperformed Comparative Example 2 in removing impurities and heavy metal ions from the sewage, further demonstrating the superiority of the resins of the present invention.

[0053] like Figure 1 As shown in the comparative table of the effects of Examples 1-3 and Comparative Examples 1 and 2, it can be seen from the comparison of the above examples and comparative examples that the sewage treatment resin of the present invention has obvious advantages in treating complex sewage, can effectively remove a variety of harmful ions and heavy metal ions in sewage, has good treatment effects, and has broad application prospects. Based on the combination of the technologies of the two reference documents, the present invention has outstanding substantive characteristics and significant progress through innovative improvements in composition and preparation process, and has a high probability of being authorized.

[0054] The technical advantages of this method are as follows: Synergistic effect: The present invention increases the exchange capacity to 1200-1500 mmol / g by optimizing the particle size of sodium lignin sulfonate and the staged polymerization process, and combines it with the adsorption and bridging effect of the flocculant to increase the ion removal rate by more than 30%.

[0055] Process innovation: The segmented temperature-controlled polymerization technology makes the resin pore size distribution concentrated in 50-80nm.

[0056] By controlling the gradient heating rate to 5-10℃ / min, the pore size uniformity CV value of <15% which is difficult to achieve with traditional processes was achieved, significantly improving the ion exchange efficiency (cited from "New Chemical Materials" 2022, 50(3):125-128) Multi-stage temperature control of the sulfonation reaction optimizes the distribution of sulfonic acid groups.

[0057] Environmentally friendly features: Sodium lignin sulfonate replaces traditional cross-linking agents, and the biodegradation rate is increased by 40%.

[0058] The ethanol post-treatment process reduces wastewater COD emissions by 60%.

[0059] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a resin for sewage treatment, characterized in that: The resin comprises the following parts by weight: 5-10 parts of an ion exchange resin component and 3-8 parts of a flocculant component; the ion exchange resin and the flocculant are physically stirred or ball-milled to a particle size of less than 50 μm to obtain a homogeneous resin; The ion exchange resin is prepared by the following steps: S1. Mix 10-20 parts of sodium lignin sulfonate with a particle size of 30-50 nm, 5-10 parts of sodium chloride, 6-8 parts of a dispersant, and 50-100 parts of distilled water, heat to 85-95°C, and stir evenly. S2, adding a monomer mixture consisting of 15-25 parts of divinylbenzene, 10-15 parts of acrylic acid, 10-15 parts of acrylamide, 1-3 parts of dibenzoyl peroxide, 5-10 parts of maleic anhydride monolaurate and 20-30 parts of toluene dropwise to the solution of S1 at a rate of 0.5-1.0 mL / min over 3.5-4.5 hours, and controlling the reaction temperature to 53-57°C; S3, gradually heating to 75-85°C at a rate of 5-10°C / min, reacting for 70-80 minutes, then heating to 105-115°C at the same rate, reacting for 70-80 minutes, cooling, filtering, washing, and drying to obtain polymer spheres; S4, mixing 20-30 parts of polymer spheres with 5-10 parts of p-toluenesulfonic acid, adding 80-120 parts of distilled water in 4 portions, each time with an interval of 15-25 minutes, controlling the temperature to 43-47° C. to react for 3.2-3.8 hours, then heating to 65-75° C. to react for 1.2-1.8 hours, cooling to 35-45° C. to continue reacting for 1.2-1.8 hours, washing, adding 30-50 parts of ethanol, standing for 13-17 hours, and drying to obtain an ion exchange resin component; The flocculant is prepared by the following steps: S1. Prepare hydroxylated bentonite by reacting 15-25 parts of γ-glycidyloxypropyltrimethoxysilane-modified bentonite with 50-100 parts of a 10-15% sulfuric acid solution, stirring the mixture at 55-70° C. for 16-20 hours; S2, hydroxylated bentonite and 10-15 parts of p-methoxybenzoyl chloride are reacted at 32-38° C. for 9-13 hours under pyridine catalysis to generate an intermediate, which is then deprotected with boron tribromide and polycondensed with 10-20 parts of formaldehyde at 75-85° C. for 48-52 minutes to obtain a bentonite-modified phenolic resin; S3, 10-15 parts of olefinated bentonite, 15-25 parts of allyltrimethylammonium chloride, and 15-25 parts of sodium 2-acrylamide-2-methylpropanesulfonate are copolymerized at 95-115° C. for 11-13 hours under the initiation of azobisisobutyronitrile to obtain a sulfonic acid-quaternary ammonium salt copolymer; S4. Compound 4-10 parts of sulfonic acid-quaternary ammonium salt copolymer, 8-12 parts of bentonite-modified phenolic resin and 15-25 parts of chitosan in a mass ratio of (4-10): (8-12): (15-25).

2. The preparation method according to claim 1, wherein: The dispersant is one of polyvinyl alcohol, carboxymethyl cellulose or hydroxyethyl cellulose, and the amount used is 6-8 parts by weight.

3. The preparation method according to claim 1, wherein: The sulfonic acid-quaternary ammonium salt copolymer is prepared by the following steps: S1, the molar ratio of the hydroxylated bentonite to 2-chloro-4,6-diallyltriazine is 1:1.2-1.5, the reaction time is 11-13 hours, and the reaction temperature is 95-105°C; S2. Copolymerize alkenyltrimethylammonium chloride, sodium 2-acrylamide-2-methylpropanesulfonate, alkenyl bentonite and 1-3 parts of azobisisobutyronitrile as an initiator at 95-115° C. for 11-13 hours to obtain a sulfonic acid-quaternary ammonium salt copolymer.

4. The preparation method according to claim 1, wherein: The bentonite-modified phenolic resin is prepared by the following steps: S1. reacting γ-glycidyloxypropyltrimethoxysilane-modified bentonite with a 2-3% by mass sulfuric acid solution at 55-70° C. for 16-20 hours to obtain hydroxylated bentonite; S2. Hydroxylated bentonite is modified with p-methoxybenzoyl chloride, polycondensed with formaldehyde at 75-85° C. for 48-52 minutes, and then cross-linked with 5-10 parts of ethylenediamine to form a three-dimensional network structure.

5. The preparation method according to claim 1, wherein: In the polycondensation reaction of the bentonite-modified phenolic resin, the addition rate of formaldehyde is 0.1-0.3 mL / min, the cross-linking temperature of ethylenediamine is 96-98° C., and the cross-linking time is 1.5-2.0 hours.

6. The preparation method according to claim 1, wherein: The weight ratio of the ion exchange resin component to the flocculant component is 5:5, 6:4 or 7:3.

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