Preparation method of porous hydrogel capable of reversibly adsorbing / releasing antibiotics and glyphosate

Abstract

The invention relates to a preparation method of porous hydrogel with reversible adsorption / release on antibiotics and glyphosate, which comprises the following steps: stirring diethylaminoethyl methacrylate, N-N methylene bisacrylamide, a polyether compound, tetrabutyl orthosilicate, a silane coupling agent (KH-570), acid, an initiator and water according to a certain proportion to form a mixed solution; and slowly dropwise adding toluene into the mixed solution, polymerizing at a certain reaction temperature, and neutralizing by using an alkali solution after polymerization to form the porous hydrogel with reversible adsorption / release on antibiotics and glyphosate. The prepared porous hydrogel has better compression resistance, and the mechanical strength reaches 0.51 MPa. The prepared porous hydrogel has high adsorption capacity on antibiotics and glyphosate. The adsorbed antibiotics and glyphosate can be released in an alkaline environment, and the obtained regenerated porous hydrogel can be repeatedly used for adsorbing the antibiotics and the glyphosate.

Description

Technical Field

[0001] The invention relates to a method for preparing a porous hydrogel capable of reversibly adsorbing / releasing antibiotics and glyphosate, belonging to the technical field of water treatment. Background Art

[0002] Antibiotics are extremely important in medical practice and are used to treat infections. Humans and animals consume large amounts of antibiotics, but most of them cannot be metabolized by animals and are excreted into sewage systems and treatment plants through urine and feces. These antibiotics cannot be biodegraded and therefore accumulate in aquatic environments. The accumulation of antibiotics in water resources leads to the emergence of antibiotic-resistant bacteria, posing a serious threat to human health. Therefore, the removal of antibiotics from wastewater is very important, but eliminating antibiotics from wastewater is a major challenge. The most commonly used conventional methods for removing antibiotics are chemical precipitation, ion exchange, adsorption, bioremediation, reverse osmosis, nanofiltration, etc. Glyphosate is an organophosphorus compound and the most commonly used active ingredient in herbicides. Due to its improper use worldwide, glyphosate has polluted the water environment and threatened the lives of aquatic organisms by making water quality unstable, poor biodegradation, and causing high concentrations of organic matter in drinking water sources. Many methods have been studied to remove glyphosate from water, including adsorption, chemical coagulation, membrane separation, and biodegradation, among others. Among these strategies, adsorption has the advantages of simple operation, low cost, and high removal rate, and is also an effective method for treating antibiotics and glyphosate in water.

[0003] The choice of adsorbent plays a vital role in adsorption. Hydrogel is a high molecular polymer that can absorb a large amount of water but is insoluble in water. There are many active functional groups on the three-dimensional network structure of the polymer main chain. Hydrogel, a functional material with hydrophilic groups and strong adsorption capacity, shows great potential in water treatment and has therefore attracted the attention of many researchers. Recently, researchers have used porous hydrogels responsive to carbon dioxide to adsorb pollutants in water. The authorized patent (ZL202010578777.1) reports a method for preparing hydrogels that swell and adsorb anionic dyes and metal ions in response to carbon dioxide. However, the reported carbon dioxide-responsive hydrogel has low mechanical properties, a compressive strength of approximately 50 kPa, and is easily broken during the adsorption operation, which will be detrimental to its actual use process. In addition, the reported hydrogel is limited to the adsorption of anionic dyes and anionic metal ions.

[0004] Therefore, finding carbon dioxide-responsive porous hydrogels with better mechanical properties and using them for reversible adsorption / release of antibiotics and glyphosate has practical significance for treating antibiotics and glyphosate in wastewater. Summary of the invention

[0005] The purpose of the present invention is to obtain carbon dioxide responsive porous hydrogels by high internal phase emulsion polymerization, and to enhance the porous hydrogels by in situ generation of nano-silica, so that the obtained porous hydrogels can be used to adsorb antibiotics and glyphosate in water. The technical scheme of the present invention is as follows: a method for preparing a porous hydrogel with reversible adsorption / release of antibiotics, the steps are as follows:

[0006] (1) diethylaminoethyl methacrylate, N,N-methylenebisacrylamide, polyether compound, tetrabutyl orthosilicate, silane coupling agent, acid, initiator and water are stirred in a certain proportion to form a mixed solution;

[0007] (2) slowly adding toluene dropwise to the mixed solution and polymerizing at 50° C. to 60° C. for 24 hours;

[0008] (3) After polymerization, the product is neutralized with alkaline water to form a porous hydrogel with reversible adsorption / release of antibiotics.

[0009] The amount of diethylaminoethyl methacrylate is 4% to 11% by mass; the amount of N,N-methylenebisacrylamide is 0.15% to 0.5% by mass; the polyether compound is a polyoxyethylene and polyoxypropylene block copolymer Pluronic (F127), and its amount is 0.5% to 2.5% by mass; the acid is 4 mol / L hydrochloric acid, sulfuric acid or nitric acid, and its amount is 5% to 15% by mass; the initiator is potassium persulfate or persulfate The amount of ammonium is 0.05% to 0.5% by mass; the amount of tetrabutyl orthosilicate is 0.5% to 4% by mass; the silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH-570), and the amount of water is 8% to 12% by mass; the amount of toluene is 65.0% to 75.0% by mass; and the alkaline water is 0.5% by mass sodium hydroxide solution.

[0010] The porous hydrogel with reversible adsorption / release of antibiotics and glyphosate can absorb water and swell after carbon dioxide is introduced, and has an adsorption effect on antibiotics and glyphosate; the porous hydrogel adsorbed with antibiotics and glyphosate can release the adsorbed antibiotics and glyphosate when treated with alkaline solution with a solution pH greater than 12, and the released porous hydrogel can be reused.

[0011] The beneficial effects of the present invention are that the porous hydrogel prepared by the present invention has higher mechanical properties and is convenient for practical operation and use; the porous hydrogel prepared by the present invention can adsorb antibiotics and glyphosate, and the adsorption process does not cause secondary pollution to the environment; after the porous hydrogel prepared by the present invention adsorbs antibiotics and glyphosate, it is treated with an alkali solution with a pH greater than 12 to release the adsorbed antibiotics and glyphosate, thereby achieving the characteristics of recycling; the preparation process of the present invention is simple, and it can be synthesized at low temperature and normal pressure through simple mixing, thereby avoiding dangerous operations under high temperature and high pressure.

[0012] Description of the accompanying tables and graphs

[0013] Figure 1 This is a flow chart for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate according to the present invention;

[0014] Figure 2 is a compressive stress-strain curve diagram of the porous hydrogel obtained in an embodiment of the present invention;

[0015] Figure 3 This is a diagram showing the water absorption ratio of the porous hydrogel obtained in an embodiment of the present invention after the introduction of carbon dioxide;

[0016] Figure 4 This is a graph showing the adsorption of antibiotics and glyphosate by the porous hydrogel obtained in an embodiment of the present invention;

[0017] Figure 5 This is a cycle diagram of tetracycline (TC) adsorption / release by the porous hydrogel obtained in an embodiment of the present invention;

[0018] Figure 6 This is a cycle diagram of glyphosate (Gly) adsorption / release by the porous hydrogel obtained in an embodiment of the present invention;

[0019] Figure 7 This is a diagram of the adsorption / release cycle of sulfamethoxazole (SMZ) by the porous hydrogel obtained in an embodiment of the present invention;

[0020] Figure 8 This is a diagram of the adsorption / release cycle of sodium ibuprofen (IB) by the porous hydrogel obtained in an example of the present invention. DETAILED DESCRIPTION

[0021] like Figure 1 Shown is a flow chart for preparing a porous hydrogel having reversible adsorption / release of antibiotics and glyphosate according to the present invention.

[0022] This embodiment is a method for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate, which is achieved by the following method:

[0023] A certain proportion of diethylaminoethyl methacrylate, N,N-methylenebisacrylamide, tetrabutyl orthosilicate, KH-570, acid, polyether compound, initiator and water are added into a reaction container and stirred into a mixed solution in a certain proportion. Toluene is slowly added dropwise into the above solution, and the reaction is carried out at 50-60° C. for 24 hours. After polymerization, the solution is neutralized to neutrality with alkaline water to form a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0024] Example 1

[0025] 4% by mass of diethylaminoethyl methacrylate, 0.5% by mass of N,N-methylenebisacrylamide, 0.564% by mass of Pluronic F-127, 1.005% by mass of tetrabutyl orthosilicate, 0.01% by mass of silane coupling agent, 15% by mass of hydrochloric acid, 0.05% by mass of ammonium persulfate, and 10.026% by mass of water are added into a reaction container, and after uniform stirring, 68.84% by mass of toluene is dropped into the mixture to mix uniformly, and the mixture is reacted at 60° C. for 24 hours. After polymerization, the mixture is neutralized to neutrality with a 0.5% by mass sodium hydroxide aqueous solution to obtain a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0026] The compressive strength versus compression strain curve of a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate obtained in this example is as follows: Figure 2 As shown. The mechanical strength of the prepared gel reaches 0.51MPa, and it will not break during the adsorption operation. After the introduction of carbon dioxide, the porous hydrogel can absorb water and swell, as shown Figure 3 As shown, the water absorption ratio can reach 55g / g.

[0027] Example 2

[0028] 7.299% by mass of diethylaminoethyl methacrylate, 0.25% by mass of N,N-methylenebisacrylamide, 1.312% by mass of Pluronic F127, 10.866% by mass of sulfuric acid, 0.277% by mass of ammonium persulfate, 9.051% by mass of water, 1.312% by mass of tetrabutyl orthosilicate, and 0.03% by mass of a silane coupling agent are added into a reaction container, and after uniform stirring, 69.849% by mass of toluene is dropped into the mixture to mix uniformly, and the mixture is reacted at 60° C. for 24 hours. After polymerization, the mixture is neutralized to neutrality with a 0.5% by mass sodium hydroxide aqueous solution to obtain a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0029] The porous hydrogel obtained in this embodiment has reversible adsorption / release of antibiotics and glyphosate. After the introduction of carbon dioxide, the porous hydrogel can absorb water and swell. Figure 3 As shown in Figure 2, the water absorption ratio can reach 60 g / g, and the adsorption energy of the antibiotic tetracycline (TC) is as follows: Figure 4 As shown in Figure 2, the adsorption amount reached 216.89 mg g -1 When the hydrogel adsorbed with TC is placed in an alkaline solution with a pH of 12, the adsorbed TC can be released and the porous hydrogel can be reused. Figure 5 As shown, after four cycles, the adsorption capacity can be maintained above 70%.

[0030] Example 3

[0031] 10.86% by mass of diethylaminoethyl methacrylate, 0.15% by mass of N,N-methylenebisacrylamide, 2.5% by mass of Pluronic F-127, 5% by mass of hydrochloric acid, 0.5% by mass of potassium persulfate, 12% by mass of water, 4% by mass of tetrabutyl orthosilicate, and 0.087% by mass of a silane coupling agent are added into a reaction container, and after uniform stirring, 65% by mass of toluene is dripped into the mixture to mix uniformly, and the mixture is reacted at 50° C. for 24 hours. After polymerization, the mixture is neutralized to neutrality with a 0.5% by mass sodium hydroxide aqueous solution to obtain a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0032] The porous hydrogel obtained in this embodiment has reversible adsorption / release of antibiotics and glyphosate. After the introduction of carbon dioxide, the porous hydrogel can absorb water and swell. Figure 3 As shown in Figure 2, the water absorption ratio can reach 66 g / g, and the adsorption energy of glyphosate (Gly) is as follows: Figure 4 As shown in Figure 2, the adsorption capacity reached 261.27 mg g -1 When the Gly-adsorbed hydrogel is placed in an alkaline solution with a pH of 13, the adsorbed Gly can be released and the porous hydrogel can be reused. Figure 6 As shown, after four cycles, the adsorption capacity can be maintained above 70%.

[0033] Example 4

[0034] 5.772% by mass of diethylaminoethyl methacrylate, 0.4% by mass of N,N-methylenebisacrylamide, 0.5% by mass of Pluronic F127, 9.892% by mass of hydrochloric acid, 0.1% by mass of ammonium persulfate, 8% by mass of water, 0.5% by mass of tetrabutyl orthosilicate, and 0.1% by mass of a silane coupling agent are added into a reaction container, and after uniform stirring, 75% by mass of toluene is dropped into the mixture to mix evenly, and the mixture is reacted at 55° C. for 24 hours. After polymerization, the mixture is neutralized to neutrality with a 0.5% by mass sodium hydroxide aqueous solution to obtain a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0035] The porous hydrogel obtained in this embodiment has reversible adsorption / release of antibiotics and glyphosate. After the introduction of carbon dioxide, the porous hydrogel can absorb water and swell. Figure 3 As shown in Figure 2, the water absorption ratio can reach 32 g / g, and the adsorption energy of the antibiotic sulfamethoxazole (SMZ) is as follows: Figure 4 As shown in Figure 2, the adsorption amount reached 210.08 mg g -1 When the hydrogel adsorbed with SMZ is placed in an alkaline solution with a pH of 12, the adsorbed SMZ can be released and the porous hydrogel can be reused. Figure 7 As shown, after four cycles, the adsorption capacity can be maintained above 65%.

[0036] Example 5

[0037] 11% by mass of diethylaminoethyl methacrylate, 0.3% by mass of N,N-methylenebisacrylamide, 0.807% by mass of Pluronic F127, 9.02% by mass of nitric acid, 0.127% by mass of potassium persulfate, 9.96% by mass of water, 2.714% by mass of tetrabutyl orthosilicate, and 0.051% by mass of a silane coupling agent are added into a reaction container, and after uniform stirring, 66.003% by mass of toluene is dropped into the mixture to mix uniformly, and the mixture is reacted at 58° C. for 24 hours. After polymerization, the mixture is neutralized to neutrality with a 0.5% by mass sodium hydroxide aqueous solution to obtain a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate.

[0038] The porous hydrogel obtained in this embodiment has reversible adsorption / release of antibiotics and glyphosate. After the introduction of carbon dioxide, the porous hydrogel can absorb water and swell. Figure 3 As shown in Figure 2, the water absorption ratio can reach 26 g / g, and the adsorption energy of the antibiotic ibuprofen sodium (IB) is as follows: Figure 4 As shown in Figure 2, the adsorption capacity reached 381.67 mg g -1When the hydrogel adsorbed with IB is placed in an alkaline solution with a pH of 14, the adsorbed IB can be released and the porous hydrogel can be reused. Figure 8 As shown, after four cycles, the adsorption capacity can be maintained above 75%.

Claims

1. A method for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate, characterized in that: The method steps are as follows: (1) diethylaminoethyl methacrylate, N,N-methylenebisacrylamide, polyether compound, tetrabutyl orthosilicate, silane coupling agent, acid, initiator and water are stirred in a certain proportion to form a mixed solution; (2) slowly adding toluene dropwise to the mixed solution and polymerizing at 50° C. to 60° C. for 24 hours; (3) After polymerization, the product was neutralized with alkaline water to form a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate. The amount of diethylaminoethyl methacrylate is 4% to 11% by mass; the amount of N,N-methylenebisacrylamide is 0.15% to 0.5% by mass; the polyether compound is a polyoxyethylene and polyoxypropylene block copolymer Pluronic (F127), and its amount is 0.5% to 2.5% by mass; the acid is 4 mol / L hydrochloric acid, sulfuric acid or nitric acid, and its amount is 5% to 15% by mass; the initiator is potassium persulfate or persulfate The amount of ammonium is 0.05% to 0.5% by mass; the amount of tetrabutyl orthosilicate is 0.5% to 4% by mass; the silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH-570), and the amount of water is 8% to 12% by mass; the amount of toluene is 65.0% to 75.0% by mass; and the alkaline water is 0.5% by mass sodium hydroxide solution.

2. The method for preparing a porous hydrogel having reversible adsorption / release of antibiotics and glyphosate according to claim 1, characterized in that: The amount of tetrabutyl orthosilicate used is 0.5% to 4% by mass.

3. The method for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate according to claim 1, characterized in that: The silane coupling agent is γ-methacryloxypropyltrimethoxysilane (KH-570), and its usage is 0.01%-0.1% by mass.

4. The method for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate according to claim 1, characterized in that: The hydrogel that swells and absorbs antibiotics is introduced with carbon dioxide to expand the gel volume, and has an adsorption effect on antibiotics and glyphosate during the gel expansion process.

5. The method for preparing a porous hydrogel with reversible adsorption / release of antibiotics and glyphosate according to claim 1, characterized in that: After the porous hydrogel adsorbs antibiotics and glyphosate, an alkaline solution with a pH greater than 12 can be used to release the adsorbed antibiotics and glyphosate, and the porous hydrogel can be reused.

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