Preparation method of porous polymer for wastewater treatment

Abstract

The invention discloses a preparation method of a porous polymer for wastewater treatment, which comprises the following steps: preparing porous gel and preparing a gel flocculant, namely preparing a gel precursor solution from acrylamide, hydroxyethyl acrylate and phenylboronic acid, mixing and reacting with an adsorbent solution, and drying to obtain porous dry gel particles; and carrying out in-situ reaction on the porous xerogel particles to graft the temperature and pH dual-response copolymer. The porous xerogel particles are used as a carrier of the ion adsorbent, the specific surface area of the material is greatly increased through the porous structure, and the adsorption capacity of ions in sewage is improved; and the temperature and pH dual response of the copolymer wrapped in the outer layer or the holes is utilized, so that outstanding flocculation adsorption and sedimentation effects are achieved in an alkaline low-temperature solution, rapid flocculation and sedimentation can be achieved through subsequent heating or acid neutralization, and subsequent dehydration reduction treatment of the flocculant is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of polymers for sewage treatment, and in particular to a preparation method of a porous polymer for wastewater treatment. Background Art

[0002] With the increasingly serious environmental pollution problems, the development of efficient, low-cost and easy-to-operate pollutant removal technologies has become an urgent need. Especially for the treatment of high-concentration saline-alkali sewage, a large amount of adsorbent is required, and at the same time, there are also problems that heavy metals are difficult to adsorb and remove.

[0003] Researchers have been committed to finding functional materials that can quickly and thoroughly remove pollutants in water. Due to their unique structural characteristics, porous polymers are considered to be a kind of adsorption material with great potential.

[0004] Porous polymers are an important type of functional materials, which have advantages such as high specific surface area, adjustable pore structure and easy functionalization modification, and are widely used in environmental protection (such as pollutant adsorption), drug delivery, tissue engineering and catalysis and other fields. The types of pollutants in sewage are diverse, including heavy metal ions, organic dyes, etc. Traditional treatment methods such as sedimentation and reverse osmosis have defects such as high cost, complex operation or poor removal effect on certain pollutants.

[0005] However, there are still some problems with existing porous polymer materials: for example, the affinity of some materials with target ions is not high, resulting in insufficient adsorption capacity; the morphology of some porous polymers is irregular, resulting in insufficient contact area with water and affecting the adsorption effect; in addition, there are still technological problems in the combined use of porous polymers and flocculants, specifically, contradictory problems such as adsorption capacity, flocculation speed and sedimentation rate all need to be solved. Summary of the Invention

[0006] The purpose of the present invention is to solve the deficiencies existing in the prior art, and to propose a preparation method of a porous polymer for wastewater treatment.

[0007] In order to achieve the above purpose, the present invention adopts the following technical scheme: A preparation method of a porous polymer for wastewater treatment, comprising the following steps: S1. Preparation of porous gel: S101. Preparation of gel precursor solution: References: Preparation and Application of High Strength-Self-Healing Polyacrylamide Hydrogel, Zheng Xiancai, Master's Thesis of Guizhou University: Acrylamide (AM), 2-hydroxyethyl acrylate (HEA) and phenylboronic acid (PBA) were added into water according to a molar ratio of 1:0.2:0.08. Water accounted for 60% of the total weight of the system. Then, disodium hydrogen phosphate accounting for 2% of the total weight of the system was added. The mixed solution was stirred under ice bath conditions until all reactants were completely dissolved; Then, N,N,N,N-tetramethylethylenediamine (TEMED) as a promoter accounting for 1% of the total weight of the system and potassium persulfate (KPS) accounting for 2% of the total weight of the system were added. The mixture was stirred at 25 - 30 °C for 3 - 5 min to obtain the gel precursor solution A, which was used immediately (used within 15 min); S102. Preparation of the hybrid gel: 1) The organic adsorbent and water were stirred and mixed at 70 °C for 30 min according to a weight ratio of 1:5, and then cooled to 5 - 10 °C to prepare the adsorbent solution; 2) The adsorbent solution, the gel precursor solution A and phenylboronic acid (PBA) were mixed at a weight ratio of 1:2:0.05 - 0.2 for 1 min, and then allowed to stand and cool to 0 - 5 °C. The mixture was poured into a mold and reacted for 3 h to obtain the wet gel B. According to literature analysis, dynamic borate bonds were formed between the PAM-HEA chains and PBA, and there were H bonds between the hydrogel polymer chains, constructing the A-H-P hydrogel with a double cross-linked network structure composed of hydrogen bonds and dynamic borate bonds that coated the adsorbent, and phenylboronic acid (PBA) was used to cross-link with the hydroxyl groups loaded on the adsorbent; 3) The wet gel B was freeze-dried and crushed to 100 - 150 mesh to obtain the porous dry gel particles C; S2. Preparation of the gel flocculant: S201. Gel encapsulation: N-isopropylacrylamide (PNIPAM), acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) were added into water according to a molar ratio of 10:4 - 6:1 - 3. Water accounted for 60% of the total weight of the system. Potassium persulfate (KPS) accounting for 2% of the total weight of the system was added. The mixture was stirred at 5 - 10 °C for 3 - 5 min, and then the porous dry gel particles C accounting for 10% of the total weight of the system were added. After swelling, the temperature was raised to 40 °C and the mixture was stirred and reacted for 2 h. The mixture was evaporated at 70 °C and 0.01 MPa until the water content was <20% to obtain the wet viscous liquid D; That is, the excess phenylboric acid remaining in the porous dry gel particles C is cross-linked with the chain side groups with hydroxyethyl acrylate (hydroxyl group), so that the surface of the porous dry gel particles C and the inner wall of the micropores are grafted with acrylamide, acrylic acid, and hydroxyethyl acrylate copolymers. The copolymer has a dual response effect of temperature response and pH response. When the temperature is lower than the response temperature Tc, the carboxyl groups in the copolymer chain form hydrogen bonds with water, showing hydrophilicity, a high water absorption and swelling rate, and a large adsorption capacity, which can improve the flocculation and sedimentation effects; when the temperature is higher than the response temperature Tc, the network hydrogen bonds are destroyed, showing hydrophobicity, The water absorption swelling rate decreases, the adsorption capacity weakens, and it is used for the later flocculant dehydration; when the pH is lower than the response pH (acidic or neutral), the copolymer chains are in a stretched state, the chain distance is closer, the swelling rate is smaller, the adsorption capacity is weakened, and it is used for the later flocculant dehydration; when the pH is higher than the response pH (alkaline), the copolymer chains are in a contracted state, the chain distance is farther, the swelling rate increases, the adsorption capacity is enhanced, and the flocculation effect can be improved; in order to expand the flocculation adsorption and sedimentation effects, it can be used for flocculation and sedimentation in alkaline low-temperature solutions, and then dehydrated and reduced by heating or acid neutralization.

[0008] S202, granulation: The wet viscous liquid D is freeze-dried and crushed into 100-150 meshes to obtain the finished porous polymer E.

[0009] Preferably, the organic adsorbent in S102 includes any one of anionic polyacrylamide [a molar ratio of amide group, carboxylic acid group and sulfonic acid group is 1:0.24:0.16, customized by Guangdong Shouxin Environmental Protection Materials Technology Co., Ltd., specifically copolymerized by acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid (AMPS)], 18-crown-6-hydroxycrown ether (purity 99%, Xi'an Qiyue Biotechnology Co., Ltd., specifically 18-crown-6 crown ether prepared by hydroxylation reaction) and COF-5 (purity>95%, Xi'an Qiyue Biotechnology Co., Ltd., specifically 1,4-phenylenediboronic acid and hexahydroxybenzophenone condensation reaction), which is used to adsorb ions, anionic polyacrylamide adsorbs alkali metal ions, and 18-crown-6-hydroxycrown ether is used to adsorb Cu 2+ , Hg 2+ or K + , COF-5 is used to adsorb various heavy metal ions.

[0010] Preferably, the conditions for neutralization of S102 and freeze-drying of S202 are -20°C and 2.0Pa.

[0011] Preferably, the weight ratio of the adsorbent solution, the gel precursor solution A and phenylboric acid (PBA) in the 102 is 1:2:0.1.

[0012] Preferably, the molar ratio of N-isopropylacrylamide (PNIPAM), acrylic acid (AA), and 2-hydroxyethyl acrylate (HEA) in S201 is 10:5:2.

[0013] The application of the obtained finished porous polymer E in sewage by the foregoing preparation method includes the following steps: putting the porous polymer E into pure water, with the weight ratio of the porous polymer E to pure water being 1-2:10, obtaining a flocculant solution after dissolution, pouring it into the sewage, so that the weight ratio of the porous polymer E to the raw sewage solution is 0.1-1:100, and performing adsorption, flocculation, and sedimentation treatments to reduce the ion concentration in the sewage.

[0014] Preferably, the sewage is specifically alkaline sewage with pH≥8.

[0015] Preferably, the treatment temperature of the sewage is 5-30°C.

[0016] Preferably, the weight ratio of the porous polymer E to the raw sewage solution is 0.5:100.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention first prepares a mixed gel by the cooperation of an adsorbent, a gel precursor solution, and phenylboronic acid. Through the preparation of the gel precursor solution, the formation of the mixed gel, and subsequent treatments, a polymer E with a porous structure is finally obtained. This porous structure greatly increases the specific surface area of the material, thereby improving the adsorption capacity for ions in sewage and endowing the porous gel with high ion adsorption ability; at the same time, the adsorbent is not easily detached, facilitating post-treatment; 2. Through the use test of a specific organic adsorbent, the present invention can further enhance the adsorption ability for specific ions (such as , etc.), that is, the present invention provides a new idea for the combined use of an adsorbent and a gel.

[0018] 3. The present invention crosslinks the residual excessive phenylboronic acid in the porous dry gel particles C with the chain side groups with 2-hydroxyethyl acrylate (hydroxyl), so that acrylamide, acrylic acid, and 2-hydroxyethyl acrylate copolymer are grafted on the surface and the inner wall of the micropores of the porous dry gel particles C. This copolymer has a dual temperature response and pH response effect, and has outstanding flocculation adsorption and sedimentation effects in an alkaline low-temperature solution. Moreover, through subsequent heating or acid neutralization, rapid flocculation and sedimentation can be achieved, facilitating the dehydration and reduction treatment of the subsequent flocculant. Specific Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the existing well-known technologies. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0020] 1. Preparation of porous gel 1. Experimental materials: Acrylamide (AM), N-isopropylacrylamide (PNIPAM), acrylic acid (AA), N,N,N,N-tetramethylethylenediamine, and disodium hydrogen phosphate were all analytically pure and purchased from Aladdin Reagent; hydroxyethyl acrylate (HEA) was analytically pure and purchased from Macklin Reagent; phenylboric acid (PBA) was analytically pure and purchased from Xushuo Reagent; potassium persulfate (KPS) was analytically pure and purchased from Jiuding Chemical.

[0021] 2. Preparation of gel precursor solution: Reference: Preparation and Application of High-Strength Self-Healable Polyacrylamide Hydrogel, Zheng Xiancai, Master's Thesis of Guizhou University: Acrylamide (AM), hydroxyethyl acrylate (HEA) and phenylboric acid (PBA) were added into water at a molar ratio of 1:0.2:0.08, with water accounting for 60% of the total weight of the system, and then sodium hydrogen phosphate accounting for 2% of the total weight of the system was added, and the mixed solution was stirred in an ice bath until all the reactants were completely dissolved; Then, add 1% of the total weight of the system as an accelerator N,N,N,N-tetramethylethylenediamine (TEMED) and 2% of the total weight of the system as potassium persulfate (KPS), and stir at 25-30°C for 3-5 minutes to obtain a gel precursor solution A, which can be used immediately (use within 15 minutes); 3. Preparation of mixed gel: 1) The organic adsorbent and water were stirred and mixed at a weight ratio of 1:5 at 70°C for 30 minutes, cooled to 5-10°C, and prepared into an adsorbent solution; The organic adsorbent includes any one of anionic polyacrylamide [the molar ratio of amide group, carboxylic acid group and sulfonic acid group is 1:0.24:0.16, customized by Guangdong Shouxin Environmental Protection Materials Technology Co., Ltd., specifically copolymerized by acrylamide, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid (AMPS)], 18-crown-6-hydroxycrown ether (purity 99%, Xi'an Qiyue Biotechnology Co., Ltd., specifically 18-crown-6 crown ether prepared by hydroxylation reaction) and COF-5 (purity>95%, Xi'an Qiyue Biotechnology Co., Ltd., specifically 1,4-phenylenediboronic acid and hexahydroxybenzophenone condensation reaction), which is used for adsorbing ions. Anionic polyacrylamide adsorbs alkali metal ions, and 18-crown-6-hydroxycrown ether is used for adsorbing Cu 2+ , Hg 2+ or K + , COF-5 is used to adsorb various heavy metal ions.

[0022] 2) Mix the adsorbent solution, gel precursor solution A, and phenylboronic acid (PBA) in a weight ratio of 1:2:0.05 - 0.2 for 1 min, let it stand and cool to 0 - 5 °C, pour it into a mold, and react for 3 h to obtain wet gel B; 3) Freeze-dry wet gel B at -20 °C and 2.0 Pa, and crush it to 100 - 150 mesh to obtain porous dry gel particles C.

[0023] In the specific preparation examples, the formulations of the mixed gels are shown in Table 1 below. The swelling properties of the obtained porous dry gel particles C in each preparation example were tested as follows: The weighing method was used to measure the swelling degree of the heavy water gel. At 25 °C, a certain mass of the hydrogel was immersed in an aqueous solution until saturation, and then the wet weight of the saturated swollen hydrogel and the dry weight of the hydrogel after drying in a vacuum oven were measured. The data were recorded and the swelling ratio (Swelling Ratio) of the hydrogel was calculated as: SR = (W t - W o ) / W o , where W o is the dry weight of the hydrogel, and W t is the wet weight of the hydrogel. All the data of the swelling property tests were averaged after being repeated three times (SR% was rounded).

[0024] Table 1. Formulations and Swelling Properties of Mixed Gels

[0025] Analyze the influence on the swelling properties from Table 1: When the content of phenylboronic acid is 0 (Comparative Preparation Example 1) or low (Preparation Example 1), the bonding between the gel network and the adsorbent may be weak, and no new cross-linked network is formed, so the water absorption efficiency is relatively high (compared with the hydrogel without adsorbent in the reference). When the content of phenylboronic acid is high (Preparation Example 4 and Comparative Preparation Example 3), the cross-linked network may be relatively dense, resulting in a decrease in the water absorption rate. Therefore, to balance the water absorption requirement and the subsequent porous requirement, Preparation Example 2 or Preparation Example 3 is selected as the preferred formulation; Selecting COF-5 (Preparation Example 5) or anionic polyacrylamide (Preparation Example 6) to replace 18-crown-6-hydroxy crown ether may result in no active hydroxyl groups coordinating with phenylboronic acid, and the water absorption rate increases slightly. Especially, anionic polyacrylamide has stronger water absorption.

[0026] II. Preparation Method of Porous Polymer 1. Preparation of Gel Flocculant: 1) Gel Encapsulation: N-isopropylacrylamide (PNIPAM), acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA) are added into water according to a molar ratio of 10:4 - 6:1 - 3. Water accounts for 60% of the total weight of the system, and potassium persulfate (KPS) accounting for 2% of the total weight of the system is added. Stir at 5 - 10 °C for 3 - 5 min, then add porous dry gel particles C accounting for 10% of the total weight of the system. After swelling, raise the temperature to 40 °C and stir and react for 2 h. Evaporate at 70 °C and 0.01 MPa until the water content is <20% to obtain a wet viscous liquid D; That is, the residual excess phenylboronic acid in the porous dry gel particles C is used to crosslink with the chain side groups with 2-hydroxyethyl acrylate (hydroxyl groups), so that acrylamide, acrylic acid, and 2-hydroxyethyl acrylate copolymers are grafted on the surface and the inner wall of the micropores of the porous dry gel particles C. This copolymer has a dual response effect of temperature response and pH response. When the temperature is lower than the response temperature Tc, the carboxyl groups in the copolymer chain form hydrogen bonds with water, showing hydrophilicity, with a higher water absorption swelling rate and a larger adsorption capacity, which can improve the flocculation and sedimentation effects; when the temperature is higher than the response temperature Tc, the network hydrogen bonds are destroyed, showing hydrophobicity, with a reduced water absorption swelling rate and a weakened adsorption capacity, which is used for the dehydration of the later flocculant; when the pH is lower than the response pH (acidic or neutral), the copolymer chain is in a stretched state, the chain distance is relatively close, the swelling rate is small, and the adsorption capacity is weakened, which is used for the dehydration of the later flocculant; when the pH is higher than the response pH (alkaline), the copolymer chain is in a contracted state, the chain distance is far, the swelling rate increases, and the adsorption capacity is enhanced, which can improve the flocculation effect; to expand the flocculation adsorption and sedimentation effects, it can be applied to flocculation and sedimentation in alkaline low-temperature solutions, and subsequent dehydration and reduction treatment are carried out by heating or acid neutralization.

[0027] 2) Granulation: The wet viscous liquid D is freeze-dried at -20 °C and 2.0 Pa and crushed to 100 - 150 mesh to obtain the finished porous polymer E.

[0028] The specific preparation process is as shown in Table 2 below: Table 2. Formulation of the gel flocculant

[0029] III. Application of the porous polymer in sewage treatment: 1. Sewage treatment method: The application of the finished porous polymer E of each example and comparative example in sewage includes the following steps: putting the porous polymer E into pure water, with the weight ratio of the porous polymer E to pure water being 1.5:10. After dissolution, a flocculant solution is obtained and poured into the sewage. The sewage selected is the chlor-alkali sewage of a certain factory (adjusted to pH 13), so that the weight ratio of the porous polymer E to the original sewage solution is 0.5:100. Adsorption, flocculation and sedimentation treatments are carried out at 25°C. After 24 hours of treatment, the ion concentration in the sewage is recorded. The performance of the finished porous polymer E of each example and comparative example in reducing the ion concentration in the sewage is shown in Table 3 below: Table 3. Treatment effect of porous polymer on sewage

[0030] It should be noted that the total VOC in Table 3 represents the content of volatile organic compounds (VOC), specifically including vinyl chloride (VCM), dichloroethane (EDC) and other volatile chlorinated hydrocarbons. Table 3 proves that the product of the present invention has a poor treatment effect on VOCs. It can be used as a pretreatment measure for aerobic treatment, which can greatly reduce the ion concentration in the sewage, treat high-concentration saline-alkali sewage into low-ion water, and then carry out special aerobic treatment to reduce the heavy metal content in the sludge; Comparing Examples 1-4 with Comparative Examples 1-2, among which phenylboronic acid is beneficial to improving the mixing ability of the adsorbent and the gel. When the amount of phenylboronic acid is too small, the cross-linking ability may be weak, resulting in the adsorbent detaching from the polymer network, being difficult to sediment and separate from the main body of the flocculant. At the same time, it increases the organic value of the sewage (not tested), thus resulting in a smaller decrease in the total amount of ions after flocculation; when the amount of phenylboronic acid is too large, the cross-linking network may be relatively dense, resulting in the difficulty for free heavy metal ions with weak free ability to adsorb into the internal adsorbent to form coordination, and also causing a smaller decrease in the total amount of heavy metal ions; Comparing Examples 5-6 with Example 2, the influence of the adsorbent is obtained: anionic polyacrylamide adsorbs alkali metal ions, and 18-crown-6-hydroxy crown ether is used to adsorb Cu 2+ , Hg 2+ or K + , and COF-5 is used to adsorb various heavy metal ions, proving that the product of the present invention can carry out encapsulated treatment with special adsorbents or compound adsorbents for sewage with different components; Comparing Examples 7-8, Comparative Examples 3-4 with Example 2, as the usage amount of the hydroxyl monomer in the responsive copolymer increases, the cross-linking degree of the porous dry gel particle C gradually increases. However, the cross-linking degree has two aspects of influence: on the one hand, a high cross-linking degree may lead to the filling of the porous structure of the porous dry gel particle C, thus resulting in a decrease in the ion adsorption ability, especially the heavy ion adsorption ability; on the other hand, a low cross-linking degree causes a decrease in the interaction force between the responsive copolymer and the porous dry gel particle C. The ion adsorption ability is relatively high, but the subsequent flocculation ability decreases and it is not easy to sediment. Therefore, the ion adsorption ability shows irregular changes.

[0031] 2. Influence of the responsive copolymer: Take the product of Example 2 to treat sewage, and adjust the ion removal rates at different pH values (pH = 11 / 9 / 7 / 5 respectively) and different temperatures (temperatures = 30 / 35 respectively) with hydrochloric acid, and calculate and The total removal rate and turbidity removal rate are shown in Table 4 and Table 5 below: Table 4. Influence of pH on ion adsorption rate

[0032] It can be seen from Table 4 that when the pH decreases (the data mutation indicates that the product of the present invention responds to pH around 7), the substitution rate of non-heavy metal ions is relatively high, but the overall adsorption capacity of the porous structure weakens and it is not conducive to sedimentation.

[0033] Table 5. Influence of temperature on ion adsorption rate

[0034] It can be seen from Table 5 that when the temperature increases (proving that the product of the present invention responds to temperatures between 30 - 35 °C), the suspension is found to have a high sedimentation rate and large particle aggregation size, resulting in a sharp decrease in turbidity, while the ion removal rate remains basically unchanged. That is, during the treatment process, the temperature can be increased or the pH can be increased for rapid sedimentation treatment, so as to achieve rapid solid-liquid separation.

[0035] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a porous polymer for wastewater treatment, characterized in that: The following steps are involved: S1. Preparation of porous gel: S101. Preparation of gel precursor solution: Acrylamide, hydroxyethyl acrylate and phenylboric acid are added into water in a molar ratio of 1:0.2:0.08, with water accounting for 60% of the total weight of the system, and then disodium hydrogen phosphate accounting for 2% of the total weight of the system is added, and the mixed solution is stirred in an ice bath until all reactants are completely dissolved; Then, 1% of the total weight of the system as an accelerator N,N,N,N-tetramethylethylenediamine and 2% of the total weight of the system as potassium persulfate were added, and stirred at 25-30° C. for 3-5 minutes to obtain a gel precursor solution A, which can be used immediately after preparation; S102, preparation of mixed gel: 1) The organic adsorbent and water were stirred and mixed at a weight ratio of 1:5 at 70°C for 30 minutes, and cooled to 5-10°C to prepare an adsorbent solution; 2) The adsorbent solution, gel precursor solution A and phenylboric acid were mixed in a weight ratio of 1:2:0.05-0.2 for 1 min, cooled to 0-5°C, poured into a mold, and reacted for 3 h to obtain wet gel B; 3) The wet gel B is freeze-dried and crushed into 100-150 meshes to obtain porous dry gel particles C; S2. Preparation of gel flocculant: S201, Gel Package: N-isopropylacrylamide, acrylic acid and hydroxyethyl acrylate are added into water in a molar ratio of 10:4-6:1-3, with water accounting for 60% of the total weight of the system, potassium persulfate accounting for 2% of the total weight of the system, stirred at 5-10°C for 3-5 minutes, and porous dry gel particles C accounting for 10% of the total weight of the system are added. After swelling, the temperature is raised to 40°C, stirred for reaction for 2 hours, and evaporated at 70°C and 0.01MPa to a water content of <20%, to obtain a wet viscous liquid D; S202, granulation: The wet viscous liquid D is freeze-dried and crushed into 100-150 meshes to obtain the finished porous polymer E.

2. The method for preparing a porous polymer for wastewater treatment according to claim 1, characterized in that: The organic adsorbent in S102 includes any one of anionic polyacrylamide, 18-crown-6-hydroxycrown ether and COF-5.

3. The method for preparing a porous polymer for wastewater treatment according to claim 1, characterized in that: The conditions for neutralizing S102 and freeze-drying S202 are -20°C and 2.0Pa.

4. The method for preparing a porous polymer for wastewater treatment according to claim 1, characterized in that: The weight ratio of the adsorbent solution, the gel precursor solution A and the phenylboric acid in the 102 is 1:2:0.

1.

5. The method for preparing a porous polymer for wastewater treatment according to claim 1, characterized in that: The molar ratio of N-isopropylacrylamide, acrylic acid and hydroxyethyl acrylate in the S201 is 10:5:

2.

6. Use of the finished porous polymer E obtained by any one of the preparation methods of claims 1 to 5 in sewage, characterized in that: The method comprises the following steps: putting a porous polymer E into pure water, wherein the weight ratio of the porous polymer E to the pure water is 1-2:10, dissolving the porous polymer E to obtain a flocculant solution, pouring the solution into sewage, wherein the weight ratio of the porous polymer E to the sewage stock solution is 0.1-1:100, and performing adsorption, flocculation and sedimentation treatment to reduce the ion concentration in the sewage.

7. The use of the finished porous polymer E in sewage according to claim 6, characterized in that: The sewage is specifically alkaline sewage with a pH value of ≥8.

8. The use of the finished porous polymer E in sewage according to claim 6, characterized in that: The treatment temperature of the sewage is 5-30°C.

9. The use of the finished porous polymer E in sewage according to claim 6, characterized in that: The weight ratio of the porous polymer E to the sewage stock solution is 0.5:100.

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