A CO2 responsive adsorption material, a preparation method thereof, and its application in treating wastewater

Abstract

The present invention discloses a CO2-responsive adsorbent material, a preparation method thereof, and its application in treating wastewater containing surfactants. The CO2-responsive adsorbent material of the present invention comprises a base sponge and a CO2-responsive polymer. The base sponge is a dopamine-coated sponge grafted with 2-bromoisobutyryl bromide. The CO2-responsive polymer is a homopolymer of any one monomer selected from a primary amine system, an amidine / guanidine system, a tertiary amine system, or a nitrogen-containing azole heterocyclic system, or a copolymer of two or more monomers. When used to treat wastewater containing anionic surfactants, the CO2-responsive adsorbent material of the present invention has a high adsorption capacity, is simple to operate, and is relatively low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, in particular to a CO2 responsive adsorption material and application thereof in treating surfactant-containing wastewater. Background Art

[0002] Surfactants, a crucial chemical product, saw sales reach 3.65 million tons in 2020. Their applications span a growing range of industries, including petroleum, shale gas, daily chemicals, detergents, pesticides, and textiles. After use, most of these substances eventually form emulsified colloids, which are discharged into the environment with wastewater, negatively impacting the physicochemical and biochemical properties of industrial and domestic wastewater. Furthermore, most of these pollutants are difficult-to-degrade organic pollutants and can be transmitted through the food chain, posing a serious threat to ecosystem balance and human health.

[0003] The adsorption method is widely used in the treatment of surfactant wastewater due to its advantages such as simple operation, green cleaning and high treatment efficiency. Surfactants are special amphiphilic substances that contain both hydrophilic and hydrophobic segments in the same molecular structure. Studies have shown that the adsorption force of materials on surfactants relies more on electrostatic forces (polar forces) and hydrophobic forces (non-polar forces). Currently, the materials commonly used for surfactant adsorption include zeolites, clay minerals, activated carbon, carbon nanotubes, chitosan, polymer resins, etc., which usually rely on electrostatic forces to adsorb surfactant pollutants. The adsorption capacity for surfactants is mostly distributed between tens and hundreds of mg / g. It is easy to reach saturation during use and requires repeated regeneration and frequent renewal, which leads to high water treatment costs and is prone to secondary pollution. For example, Tan Wenyuan applied alkali and hexadecyltrimethylammonium bromide modified natural zeolite to the adsorption of linear alkylbenzene sulfonate sodium, and the saturated adsorption capacity was measured to be only 25.31 mg / g (Research on the Modification and Characterization of Natural Zeolite and Its Application in Removing LAS from Domestic Wastewater [D]. Chengdu University of Technology, 2016); Ncibi Mohamed Chaker et al. synthesized multi-walled carbon nanotubes and used them for the adsorption of hexadecylbenzene sulfonate sodium, and the adsorption capacity was measured to be 312 mg / g (Ncibi Mohamed Chaker, Gaspard Sarra, Mika. As-synthesized multi-walled carbon nanotubes for the removal of ionic and non-ionic surfactants[J]. Journal of Hazardous Materials, 2015, 286: 195-203).

[0004] Therefore, how to develop a new adsorption material with easy operation and high adsorption capacity based on the characteristics of surfactants has become an urgent problem to be solved. Summary of the Invention

[0005] In response to the problems of high cost, small adsorption capacity and complicated operation in the existing technology when treating surfactant wastewater by adsorption method, the present invention provides a method for treating surfactant pollutants in wastewater using CO2-responsive materials. This type of material exhibits a significantly higher adsorption capacity for typical surfactant pollutants, and is simple to operate and low in cost.

[0006] The first aspect of the present invention provides a CO2-responsive adsorption material, comprising a base sponge and a CO2-responsive polymer, wherein the base sponge is a dopamine-coated sponge grafted with 2-bromoisobutyryl bromide (BiBB), and the CO2-responsive polymer is a homopolymer of any one monomer selected from a primary amino system, an amidine / guanidine system, a tertiary amino system, or a nitrogen-containing azole heterocyclic system, or a copolymer of two or more monomers.

[0007] In the present invention, the monomer of the primary amine system is selected from at least one of allylamine (AA), N-methyl-N-vinylformamide (MVF), and di-N-vinylformamide (DVEF), preferably allylamine (AA); the monomer of the amidine / guanidine system is selected from at least one of N-amidinododecylacrylamide (ADA) and N'-acryloyl-N, N-dimethylethylamidine (ADMEA), preferably N-amidinododecylacrylamide (ADA); the monomer of the tertiary amine system is selected from at least one of allylamine (AA), N-methyl-N-vinylformamide (MVF), and di-N-vinylformamide (DVEF), preferably allylamine (AA); the monomer of the amidine / guanidine system is selected from at least one of N-amidinododecylacrylamide (ADA) and N'-acryloyl-N, N-dimethylethylamidine (ADMEA), preferably N-amidinododecylacrylamide (ADA); The monomer is selected from at least one of diethylaminoethyl methacrylate (DEAEMA), dimethylaminoethyl methacrylate (DMAEMA), and N,N-dimethylphenylene glycol (DMSt), preferably diethylaminoethyl methacrylate (DEAEMA), and the monomer containing the nitrogen azole heterocyclic system is selected from at least one of 3(1H-imidazole-4-yl)methyl acrylate (MIA) and imidazoleethyl methacrylate (IEMA), preferably 3(1H-imidazole-4-yl)methyl acrylate (MIA).

[0008] In the present invention, the sponge is selected from polyurethane (PU) sponge, melamine (MA) sponge, carbon (C) sponge or polyether (PE) sponge.

[0009] In the present invention, the mass ratio of the base sponge to the CO2 responsive polymer is 1:200-1:50.

[0010] In the present invention, the mass ratio of 2-bromoisobutyryl bromide (BiBB) to the sponge is 2:1-7.5:1, and the mass ratio of dopamine to the sponge is 1:1-5:1.

[0011] A second aspect of the present invention provides a method for preparing the above-mentioned CO2-responsive adsorption material, comprising:

[0012] (1) adding dopamine hydrochloride and a sponge to a tris(hydroxymethylaminomethane) buffer solution to carry out a polymerization reaction to obtain a dopamine-coated sponge;

[0013] (2) adding the dopamine-coated sponge obtained in step (1) into a dimethylformamide solvent, adding an acid binding agent, and then dropwise adding 2-bromoisobutyryl bromide (BiBB), and reacting under an inert atmosphere (such as nitrogen) to obtain a BiBB-grafted dopamine-coated sponge;

[0014] (3) adding the CO2-responsive monomer to the mixed solvent, adding a chelating agent, a catalyst, the BiBB-grafted dopamine-coated sponge obtained in step (2), and a reducing agent under an inert atmosphere (such as nitrogen), stopping the inert gas flow and sealing the reaction vessel to carry out a polymerization reaction to obtain the CO2-responsive adsorption material.

[0015] In the method of the present invention, in step (1), the concentration of the tris(hydroxymethyl)aminomethane buffer solution is 2-10 mmol / L, and the pH value is 8.0-9.0.

[0016] In the method of the present invention, in step (1), the sponge is washed with ethanol and acetone before use, and then dried for standby use; the sponge is selected from polyurethane (PU) sponge, melamine (MA) sponge, carbon (C) sponge or polyether (PE) sponge.

[0017] In the method of the present invention, in step (1), the polymerization reaction is carried out in a shaker with a shaker speed of 150-300 rpm, a polymerization time of 10-60 min, normal pressure, and a temperature of 25-40°C.

[0018] In the method of the present invention, in step (1), in the method for preparing the dopamine-coated sponge, conventional post-treatment, such as washing and drying, is performed after the polymerization reaction. The washing and drying can be performed in any manner conventionally known in the art, wherein washing can be performed with ultrapure water and / or ethanol. The drying temperature can be selected from 25-90° C., preferably 50-80° C.; the drying time can be selected from 0.5-6 hours, preferably 0.5-2 hours. The drying can be performed under normal pressure or under reduced pressure. To save energy, normal pressure is usually selected.

[0019] In the method of the present invention, in step (2), the acid binding agent is selected from triethylamine (TEA), diisopropylethylamine (DIEA) or a mixture of triethylamine and magnesium chloride, and the molar ratio of TEA:MgCl2 in the mixture of triethylamine and magnesium chloride is 1.2:1-2:1.

[0020] In the method of the present invention, in step (2), the molar ratio of BiBB to the acid binding agent is 1:1-1.2:1.

[0021] In the method of the present invention, in step (2), the reaction of the dopamine-coated sponge and BiBB includes first reacting at a temperature of 0-4°C and a pressure of normal pressure for 1-2 hours, and then reacting at a temperature of 20-30°C and a pressure of normal pressure for 1-4 hours.

[0022] In the method of the present invention, in step (2), in the method for preparing the BiBB-grafted dopamine-coated sponge, after the reaction, the mixture is first washed with ultrapure water and / or ethanol, and then placed in a mixed solvent of a low-carbon alcohol and water, wherein the volume ratio of the low-carbon alcohol to water in the mixed solvent is 1:1-2:1. The low-carbon alcohol is preferably at least one of methanol and isopropanol.

[0023] In the method of the present invention, in step (3), the CO2-responsive monomer is selected from at least one monomer of a primary amino system, an amidine / guanidine system, a tertiary amino system or a nitrogen-containing azole heterocyclic system, wherein the monomer of the primary amino system is preferably allylamine (AA), the monomer of the amidine / guanidine system is preferably N-amidinododecyl acrylamide (ADA), the monomer of the tertiary amino system is preferably diethylaminoethyl methacrylate (DEAEMA), and the monomer of the nitrogen-containing azole heterocyclic system is preferably 3(1H-imidazole-4-yl)methyl acrylate (MIA).

[0024] In the method of the present invention, in step (3), the mixed solvent is selected from a mixed solution of methanol / water or a mixed solution of isopropanol / water, and the volume ratio of the mixed solvent is 1:1-2:1.

[0025] In the method of the present invention, in step (3), the complexing agent is selected from at least one of bipyridine (Bpy), tris-(2-pyridylmethyl)amine (TPMA) or pentamethyldiethylenetriamine (PMDETA).

[0026] In the method of the present invention, in step (3), the catalyst is selected from at least one of copper chloride (CuCl2·2H2O), copper bromide or ferric chloride, and the reducing agent is selected from at least one of ascorbic acid, stannous octoate or glucose.

[0027] In the method of the present invention, in step (3), the mass ratio of the CO2 response monomer to the mixed solvent is 1:2-1:15, the molar ratio of the CO2 response monomer to the complexing agent is 200:1-50:1, the molar ratio of the CO2 response monomer to the catalyst is 1000:1-500:1, and the molar ratio of the catalyst to the reducing agent is 1:20-1:65.

[0028] In the method of the present invention, in step (3), the polymerization reaction time is 3-18 hours, the pressure is normal pressure, and the temperature is 25-60°C.

[0029] In the method of the present invention, in step (3), in the method for preparing the CO2-responsive adsorbent material, conventional post-treatment, such as washing and drying, is performed after the polymerization reaction. The washing and drying can be performed in any manner conventionally known in the art, wherein washing can be performed with ultrapure water and / or ethanol. The drying temperature can be selected from 30-90°C, preferably 50-80°C; the drying time can be selected from 0.5-6 hours, preferably 2-3 hours. The drying can be performed under normal pressure or under reduced pressure. To save energy, normal pressure is often selected.

[0030] A third aspect of the present invention provides an application of the above-mentioned CO2-responsive adsorption material in treating surfactant-containing wastewater, comprising:

[0031] The CO2 responsive adsorption material is placed in wastewater containing a surfactant for adsorption, and its saturated adsorption capacity is recorded as Q0; or the CO2 responsive adsorption material is pre-treated with CO2 purge and then placed in wastewater containing a surfactant for adsorption, and its saturated adsorption capacity is recorded as Q1.

[0032] In the method of the present invention, the surfactant is an anionic surfactant, preferably at least one of sodium dodecylbenzenesulfonate (SDBS), perfluorooctanoic acid (PFOA), and sodium cyclohexanecarboxylate (NAS), and the concentration of the surfactant in the wastewater is 10 to 1000 mg / L, for example but not limited to 10 mg / L, 50 mg / L, 100 mg / L, 250 mg / L, 400 mg / L, 500 mg / L, 600 mg / L, 750 mg / L, 900 mg / L, and 1000 mg / L.

[0033] In the method of the present invention, the adsorption process is carried out in a shaking table, the shaking table rotation speed is 200-300 rpm, and the adsorption time is 0.5-2h.

[0034] In the method of the present invention, relative to 10 mg of CO2 responsive adsorption material, the CO2 purge gas flow rate is 100-300 mL / min, and the purge time is 2-30 min.

[0035] In the method of the present invention, preferably, the saturated adsorption capacity Q1 is at least 300 mg / g higher than the saturated adsorption capacity Q0.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The inventors have found through research that the adsorption of surfactant pollutants in wastewater mainly relies on the electrostatic force (polar force) between the adsorption material and the surfactant, and the adsorption capacity is relatively small. The inventors have further found that after the sponge is coated with dopamine and grafted with 2-bromoisobutyryl bromide (BiBB), the CO2-responsive monomer is polymerized on the sponge. The resulting CO2-responsive polymer grafted sponge, that is, the CO2-responsive adsorption material, is used to remove surfactant pollutants. On the one hand, based on the structural characteristics of the CO2-responsive material, the molecule contains both hydrophobic alkyl chain ends and hydrophilic amino chain ends, which can simultaneously exert hydrophobic non-polar forces and hydrophilic polar forces on the pollutant molecules, thereby strengthening the interaction between the pollutants and the adsorption material and improving the adsorption capacity of the material for surfactant pollutants; further, the CO2-responsive material is first purged with CO2 gas, and the amino, amidine, guanidine or imidazole groups in the material are protonated, so that the material has a positive charge, and the polar electrostatic attraction between the material and the pollutants is enhanced, which can further improve the adsorption capacity.

[0038] 2. The CO2 responsive adsorption material of the present invention has gas responsive characteristics and can use CO2 gas purging as a pretreatment method. This method is green, environmentally friendly and efficient. It can also be used as a means of CO2 gas absorption and reuse, which is in line with the national carbon emission reduction and carbon neutrality policy orientation, and can improve the material's adsorption performance for surfactant pollutants, thereby achieving the purpose of energy conservation and emission reduction, and therefore has important economic and environmental benefits.

[0039] 3. The CO2-responsive adsorption material of the present invention exhibits a high adsorption capacity for perfluoroalkanoic acid and cycloalkanoic acid pollutants. Due to their difficult-to-degrade characteristics, the above-mentioned pollutants are currently difficult to treat among organic pollutants. In particular, perfluoroalkanoic acids have been listed as new persistent organic pollutants (POPs). Therefore, the present invention can provide a simple and efficient method for the treatment of difficult-to-degrade pollutants. DETAILED DESCRIPTION

[0040] The following is a more detailed description of the preparation method of the CO2 responsive adsorption material of the present invention through specific examples. The examples are only illustrative of the specific implementation methods of the method of the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0041] Determination of adsorption capacity: The concentration of surfactant in wastewater was determined using liquid chromatography-mass spectrometry (LCMS-8050, Shimadzu, Japan). The adsorption capacity of the material for different surfactants was calculated based on the amount of material added and the surfactant concentration before and after the adsorption process. The calculation formula is as follows:

[0042]

[0043] Where Q is the adsorption capacity, C0 and C are the surfactant concentrations before and after adsorption, V is the wastewater volume, and m is the mass of the CO2-responsive adsorption material.

[0044] Example 1

[0045] Preparation of CO2 responsive adsorption materials:

[0046] (1) The polyurethane (PU) sponge was washed several times with ethanol and acetone, and dried at 60°C for later use. 100 mL of tris(hydroxymethyl)aminomethane buffer solution (pH = 8.5, 10 mmol / L) was prepared, and dopamine hydrochloride (2.1 mmol) and 140 mg of dry PU sponge were added to initiate the polymerization of dopamine on the surface of the PU sponge. This process was continued at 30°C in a shaker at 250 rpm for 0.5 h to obtain a dopamine-coated polyurethane (PU) sponge. After the polymerization was completed, the sponge was removed, thoroughly washed with ultrapure water, and dried at 50°C for 2 h for later use.

[0047] (2) Triethylamine (TEA) (2.10 mmol) was added to a reaction flask containing 20 mL of dimethylformamide (DMF). The flask was placed in an ice-water bath and dry nitrogen was continuously bubbled into the solution for 20 min. The dopamine-coated polyurethane (PU) sponge obtained in step (1) was then added. Subsequently, 2-bromoisobutyryl bromide (BiBB) (2.10 mmol) was dissolved in 5 mL of DMF and added dropwise to the TEA and DMF mixture. The reaction was carried out under nitrogen atmosphere at 0°C for 1 h and then at 25°C for 3 h. After the reaction was completed, the sponge was removed, thoroughly rinsed with ethanol and ultrapure water, and placed in a mixture of isopropanol and water (volume ratio 1:1) for later use. The resulting sponge was PU-BiBB.

[0048] (3) Diethylaminoethyl methacrylate (DEAEMA) monomer (45 mmol) was dissolved in 30 mL of a 1:1 isopropanol / water mixed solvent. N2 was bubbled into the mixed solution for approximately 10 minutes. Tris-(2-pyridylmethyl)amine (TPMA) (0.48 mmol) was dissolved in 10 mL of a 1:1 isopropanol / water mixed solvent. The mixture was then added to the mixed solution. Subsequently, CuCl2·2H2O (75 μmol) was weighed and dissolved in 10 mL of a 1:1 isopropanol / water mixed solvent. The mixture was then added to the mixed solution. The sponge obtained in step (2) and stored in a 1:1 isopropanol / water mixed solvent was then added. After continuing to bubble N₂ for approximately 10 minutes, ascorbic acid (2.84 mmol) was dissolved in 10 mL of a 1:1 volume ratio of isopropanol / water mixture and added to the resulting mixture. The N₂ flow was stopped, and the reaction vessel was sealed to initiate polymerization of DEAEMA on the sponge surface. The polymerization reaction continued at 60°C for 3 hours, after which the reaction solution was exposed to the air to terminate the reaction. The sponge was removed, thoroughly rinsed with ethanol and ultrapure water, and dried in a 60°C drying oven for 2 hours to obtain a PDEAEMA-grafted PU sponge (PU-PDEAEMA).

[0049] CO2 responsive adsorption materials for the removal of surfactant pollutants:

[0050] At an initial perfluorooctanoic acid (PFOA) concentration of 700 mg / L, 10 mg of the CO2-responsive adsorbent PU-PDEAEMA was added to 50 mL of the pollutant solution and placed on a shaker at 250 rpm for 2 hours to investigate the material's saturated adsorption capacity for the pollutant. The residual PFOA concentration in the solution was determined using a liquid chromatography-mass spectrometer (LCMS-8050, Shimadzu, Japan). The saturated adsorption capacity of PU-PDEAEMA for PFOA was determined to be 1962 mg / g.

[0051] A 10-minute purge pretreatment of 10 mg of the CO2-responsive adsorbent material, PU-PDEAEMA, was performed with a CO2 gas flow rate of 200 mL / min. The pretreated PU-PDEAEMA was then used to adsorb PFOA, and its saturated adsorption capacity for PFOA was measured to be 2598 mg / g.

[0052] Example 2

[0053] Preparation of CO2 responsive adsorption materials:

[0054] (1) The melamine (MA) sponge was washed several times with ethanol and acetone, and dried at 60°C for later use. 100 mL of tris(hydroxymethyl)aminomethane buffer solution (pH = 8.7, 5 mmol / L) was prepared, and dopamine hydrochloride (1 mmol) and 130 mg of dried MA sponge were added to initiate the polymerization of dopamine on the surface of the MA sponge. This process was continued at 25°C in a shaker at 150 rpm for 1 hour to obtain a dopamine-coated melamine (MA) sponge. After the polymerization was completed, the sponge was removed, thoroughly washed with ultrapure water, and dried at 80°C for 0.5 hour for later use.

[0055] (2) Diisopropylethylamine (DIEA) (4 mmol) was added to a reaction flask containing 20 mL of dimethylformamide (DMF). The flask was placed in an ice-water bath and dry nitrogen was continuously bubbled into the solution for 20 min. The dopamine-coated melamine (MA) sponge obtained in step (1) was then added. Subsequently, 2-bromoisobutyryl bromide (BiBB) (4 mmol) was dissolved in 5 mL of DMF and added dropwise to the DIEA and DMF mixture. The reaction was carried out under nitrogen at 0°C for 2 h and then at 25°C for another 4 h. After the reaction was completed, the sponge was removed, thoroughly rinsed with ethanol and ultrapure water, and placed in a mixture of isopropanol and water (volume ratio of 1.5:1) for later use. The resulting sponge was MA-BiBB.

[0056] (3) N-amidinododecyl acrylamide (ADA) monomer (90 mmol) was dissolved in 30 mL of a mixed solvent of isopropanol / water (volume ratio of 1.5:1). N2 was bubbled into the mixed solution for approximately 10 minutes. Pentamethyldiethylenetriamine (PMDETA) (1.2 mmol) was dissolved in 10 mL of a mixed solvent of isopropanol / water (volume ratio of 1.5:1) and added to the mixed solution. Subsequently, CuBr2 (180 μmol) was weighed and dissolved in 10 mL of a mixed solvent of isopropanol / water (volume ratio of 1.5:1). The mixture was then added to the mixed solution. The sponge obtained in step (2) and stored in a mixed solvent of isopropanol / water (volume ratio of 1.5:1) was also added. After continuing to bubble N₂ for approximately 10 minutes, glucose (4.5 mmol) was dissolved in 10 mL of a 1.5:1 volume ratio of isopropanol / water and added to the mixture. The N₂ flow was stopped, and the reaction vessel was sealed to initiate ADA polymerization on the sponge surface. The polymerization reaction continued at 40°C for 8 hours, after which the reaction solution was exposed to terminate the reaction. The sponge was removed, thoroughly rinsed with ethanol and ultrapure water, and dried in an 80°C drying oven for 2.5 hours to obtain an ADA-grafted MA sponge (MA-ADA).

[0057] CO2 responsive adsorption materials for the removal of surfactant pollutants:

[0058] At an initial sodium dodecylbenzenesulfonate (SDBS) concentration of 1000 mg / L, 10 mg of the CO2-responsive adsorbent MA-ADA was added to 50 mL of a pollutant solution. The solution was shaken at 300 rpm for 0.5 h to investigate the material's saturated adsorption capacity for the pollutant. The residual SDBS concentration in the solution was determined using a liquid chromatography-mass spectrometer (LCMS-8050, Shimadzu, Japan). The saturated adsorption capacity of MA-ADA for SDBS was determined to be 1867 mg / g.

[0059] A 5-minute purge pretreatment of 10 mg of the CO2-responsive adsorbent material, MA-ADA, was performed with a CO2 gas flow rate of 300 mL / min. The pretreated MA-ADA was then used to adsorb SDBS, and the saturated adsorption capacity for SDBS was measured to be 2396 mg / g.

[0060] Example 3

[0061] Preparation of CO2 responsive adsorption materials:

[0062] (1) The carbon (C) sponge was washed several times with ethanol and acetone, and dried at 60°C for later use. 100 mL of tris (hydroxymethyl)aminomethane buffer solution (pH = 9, 10 mmol / L) was prepared, and dopamine hydrochloride (2 mmol) and 80 mg of dried C sponge were added to initiate polymerization of dopamine on the surface of the C sponge. This process was continued at 25°C and 300 rpm in a shaker for 10 min to obtain a dopamine-coated carbon (C) sponge. After the polymerization was completed, the sponge was removed, thoroughly washed with ultrapure water, and dried at 70°C for 1 h for later use.

[0063] (2) A mixture of triethylamine (TEA) and magnesium chloride (MgCl2) (2 mmol, wherein the molar ratio of TEA:MgCl2 is 1.5:1) is added to a reaction flask containing 20 mL of dimethylformamide (DMF). The reaction flask is placed in an ice-water bath and dry nitrogen is continuously bubbled into the solution for 20 min. The dopamine-coated carbon (C) sponge obtained in step (1) is then added. Subsequently, 2-bromoisobutyryl bromide (BiBB) (2.4 mmol) is dissolved in 5 mL of DMF and added dropwise to the mixed solution of TEA, MgCl2, and DMF. The reaction is carried out under nitrogen atmosphere at 0°C for 2 h and then at 25°C for another 2 h. After the reaction is completed, the sponge is removed, thoroughly cleaned with ethanol and ultrapure water, and placed in a mixed solution of isopropanol / water (volume ratio 1:1) for later use. The resulting sponge is C-BiBB.

[0064] (3) Allylamine (AA) monomer (72 mmol) was dissolved in 30 mL of a mixed solvent of isopropyl alcohol / water (volume ratio of 1:1), and N2 was bubbled into the mixed solution for about 10 min. Bipyridyl (Bpy) (1.2 mmol) was dissolved in 10 mL of a mixed solvent of isopropyl alcohol / water (volume ratio of 1:1), and added to the mixed solution. Subsequently, FeCl3 (90 μmol) was weighed and dissolved in 10 mL of a mixed solvent of isopropyl alcohol / water (volume ratio of 1:1), and added to the mixed solution. The sponge obtained in step (2) and stored in the mixed solvent of isopropyl alcohol / water (volume ratio of 1:1) was added. After continuing to bubble N2 for about 10 min, stannous octoate (3 mmol) was dissolved in 10 mL of a mixed solvent of isopropyl alcohol / water (volume ratio of 1:1), and added to the mixed solution. The N2 was stopped, and the reaction vessel was sealed to initiate the polymerization reaction of AA on the sponge surface. After the polymerization reaction continued at 60°C for 10 hours, the reaction solution was opened to terminate the reaction, the sponge was taken out, thoroughly washed with ethanol and ultrapure water, and placed in a drying oven at 50°C for 3 hours to obtain AA-grafted C sponge (AA-C).

[0065] 2. CO2 responsive adsorption materials for the removal of surfactant pollutants

[0066] At an initial sodium naphthenate (NAS) concentration of 1000 mg / L, 10 mg of the CO2-responsive adsorbent AA-C was added to 50 mL of the pollutant solution. The solution was shaken at 200 rpm for 1.5 hours to investigate the material's saturated adsorption capacity for the pollutant. The residual NAS concentration in the solution was determined using liquid chromatography-mass spectrometry (LCMS-8050, Shimadzu, Japan). The saturated adsorption capacity of AA-C for NAS was determined to be 1324 mg / g.

[0067] A 10 mg portion of the CO2-responsive adsorbent material AA-C was pretreated with a purge gas flow rate of 100 mL / min for 30 minutes. The pretreated AA-C was then used to adsorb NAS, and the saturated adsorption capacity of AA-C for NAS was measured to be 1696 mg / g.

[0068] Example 4

[0069] Preparation of CO2 responsive adsorption materials:

[0070] (1) The polyether (PE) sponge was washed several times with ethanol and acetone, and dried at 60°C for later use. 100 mL of tris (hydroxymethyl)aminomethane) buffer solution (pH = 8, 2 mmol / L) was prepared, and dopamine hydrochloride (0.5 mmol) and 90 mg of dry PE sponge were added to initiate the polymerization of dopamine on the surface of the PE sponge. This process was continued at 30°C and 300 rpm in a shaker for 10 min to obtain a dopamine-coated polyether (PE) sponge. After the polymerization was completed, the sponge was removed, thoroughly washed with ultrapure water, and dried at 80°C for 0.5 h for later use.

[0071] (2) Triethylamine (TEA) (2 mmol) was added to a reaction flask containing 20 mL of dimethylformamide (DMF), and the flask was placed in an ice-water bath. Dry nitrogen was continuously bubbled into the solution for 20 min, and then the dopamine-coated polyether (PE) sponge obtained in step (1) was added. Subsequently, 2-bromoisobutyryl bromide (BiBB) (2.2 mmol) was dissolved in 5 mL of DMF and added dropwise to the TEA and DMF mixture. The reaction was carried out under N2 atmosphere at 0°C for 1 h, and then at 25°C for another 1 h. After the reaction was completed, the sponge was removed, thoroughly cleaned with ethanol and ultrapure water, and placed in an isopropanol / water mixture (volume ratio of 1:1) for later use. The resulting sponge was PE-BiBB.

[0072] (3) Methyl 3(1H-imidazol-4-yl)acrylate (MIA) monomer (30 mmol) was dissolved in 30 mL of a 1:1 isopropanol / water mixture, and nitrogen was bubbled through the mixture for approximately 10 minutes. Tris-(2-picolylamine) (TPMA) (0.3 mmol) was dissolved in 10 mL of a 1:1 isopropanol / water mixture and added to the mixture. Subsequently, 30 μmol of CuCl₂·2H₂O was weighed and dissolved in 10 mL of a 1:1 isopropanol / water mixed solvent. The mixture was then added to the above-mentioned mixed solution. The sponge obtained in step (2) and stored in the 1:1 isopropanol / water mixed solvent was then added. N₂ was continued to bubble through the mixture for approximately 10 minutes. Ascorbic acid (1.8 mmol) was then dissolved in 10 mL of a 1:1 isopropanol / water mixed solvent. The mixture was then added to the above-mentioned mixed solution. The N₂ flow was stopped, and the reaction vessel was sealed to initiate polymerization of MIA on the sponge surface. The polymerization reaction continued at 25°C for 18 hours. The reaction solution was then opened to terminate the reaction. The sponge was removed, thoroughly rinsed with ethanol and ultrapure water, and dried in an 80°C drying oven for 2.5 hours to obtain an MIA-grafted PE sponge (PE-MIA).

[0073] CO2 responsive adsorption materials for the removal of surfactant pollutants:

[0074] At an initial perfluorooctanoic acid (PFOA) concentration of 700 mg / L, 10 mg of the CO2-responsive adsorbent PE-MIA was added to 50 mL of the pollutant solution and placed on a shaker at 200 rpm for 2 hours to investigate the material's saturated adsorption capacity for the pollutant. The residual PFOA concentration in the solution was determined using liquid chromatography-mass spectrometry (LCMS-8050, Shimadzu, Japan). The saturated adsorption capacity of PE-MIA for PFOA was determined to be 1235 mg / g.

[0075] A 10-minute purge pretreatment of 10 mg of the CO2-responsive adsorbent material, PE-MIA, was performed with a CO2 gas flow rate of 200 mL / min. The pretreatment was then used to adsorb PFOA, and the saturated adsorption capacity of PE-MIA for PFOA was measured to be 1589 mg / g.

[0076] Comparative Example 1

[0077] Substituting an equal amount of zeolite for the PU-PDEAEMA in Example 1, with all other experimental parameters remaining the same, the zeolite's saturated adsorption capacity for PFOA was found to be 90 mg / g. The zeolite pretreated with CO2 gas also had a saturated adsorption capacity for PFOA of 90 mg / g.

[0078] Comparative Example 2

[0079] By replacing the PU-PDEAEMA in Example 1 with an equal amount of granular activated carbon (GAC), and with all other experimental parameters remaining the same, the saturated adsorption capacity of GAC for PFOA was measured to be 161 mg / g. The saturated adsorption capacity of GAC for PFOA after CO2 gas purge pretreatment was 163 mg / g.

[0080] Comparative Example 3

[0081] By replacing the PU-PDEAEMA in Example 1 with an equal amount of powdered activated carbon (PAC) and maintaining the same experimental parameters, the saturated adsorption capacity of PAC for PFOA was found to be 277 mg / g. The saturated adsorption capacity of PAC for PFOA after CO2 gas pretreatment was found to be 275 mg / g.

[0082] Comparative Example 4

[0083] When PU-PDEAEMA in Example 1 was replaced with an equal amount of chitosan and all other experimental parameters were the same, the saturated adsorption capacity of chitosan for PFOA was 657 mg / g. The saturated adsorption capacity of chitosan for PFOA after CO2 gas purge pretreatment was 660 mg / g.

[0084] Comparative Example 5

[0085] Substituting an equal amount of ion exchange resin AmberLite IRA400 for PU-PDEAEMA in Example 1, with all other experimental parameters remaining the same, the saturated adsorption capacity of AmberLite IRA400 for PFOA was measured to be 1203 mg / g. The saturated adsorption capacity of AmberLite IRA400 for PFOA after CO2 gas pretreatment was 1205 mg / g.

[0086] Comparative Example 6

[0087] Substituting an equal amount of ion exchange resin AmberLite IRA910 for the PU-PDEAEMA in Example 1, with all other experimental parameters remaining the same, the saturated adsorption capacity of AmberLite IRA910 for PFOA was measured to be 1437 mg / g. The saturated adsorption capacity of AmberLite IRA910 for PFOA after CO2 gas purge pretreatment was also 1437 mg / g.

[0088] Comparative Example 7

[0089] The CO2-responsive adsorbent material PU@PDEAEMA was prepared according to the method disclosed in patent CN111285433B, with an equal amount of PU@PDEAEMA replacing PU-PDEAEMA. Other experimental parameters were identical to those in Example 1. The saturated adsorption capacity of PU@PDEAEMA for PFOA was measured to be 1803 mg / g. The saturated adsorption capacity of PU@PDEAEMA for PFOA after CO2 gas purge pretreatment was 2337 mg / g.

Claims

1. Application of a CO2-responsive adsorption material in treating surfactant-containing wastewater, comprising: The CO2 responsive adsorption material is pre-treated by CO2 purge and then placed in wastewater containing surfactant for adsorption; The CO2 responsive adsorption material is placed in wastewater containing a surfactant for adsorption, and its saturated adsorption capacity is recorded as Q0; the CO2 responsive adsorption material is subjected to CO2 purge pretreatment and then placed in wastewater containing a surfactant for adsorption, and its saturated adsorption capacity is recorded as Q1; the saturated adsorption capacity Q1 is at least 300 mg / g higher than the saturated adsorption capacity Q0; the surfactant is an anionic surfactant, selected from at least one of sodium dodecylbenzenesulfonate, perfluorooctanoic acid, and sodium cyclohexane. The CO2 responsive adsorption material comprises a base sponge and a CO2 responsive polymer, wherein the base sponge is a dopamine-coated sponge grafted with 2-bromoisobutyryl bromide, and the CO2 responsive polymer is a homopolymer of any one monomer selected from a primary amine system, an amidine system, a guanidine system, a tertiary amine system, or a nitrogen-containing azole heterocyclic system, or a copolymer of two or more monomers; The method for preparing the CO2-responsive adsorption material comprises: (1) Adding dopamine hydrochloride and sponge to a tris(hydroxymethylaminomethane) buffer solution to carry out polymerization reaction to obtain a dopamine-coated sponge; (2) adding the dopamine-coated sponge obtained in step (1) into a dimethylformamide solvent, adding an acid-binding agent, and then dropwise adding 2-bromoisobutyryl bromide (BiBB), and reacting under an inert atmosphere to obtain a BiBB-grafted dopamine-coated sponge; (3) adding the CO2 responsive monomer to a mixed solvent, adding a complexing agent, a catalyst, the BiBB-grafted dopamine-coated sponge obtained in step (2), and a reducing agent under an inert atmosphere, stopping the inert gas flow and sealing the reaction vessel to carry out a polymerization reaction to obtain the CO2 responsive adsorption material; In step (2), the reaction of the dopamine-coated sponge with BiBB comprises first reacting at a temperature of 0-4°C and a pressure of normal pressure for 1-2 hours, and then reacting at a temperature of 20-30°C and a pressure of normal pressure for 1-4 hours.

2. The use according to claim 1, characterized in that The monomer of the primary amino system is selected from at least one of allylamine, N-methyl-N-vinylformamide, and di-N-vinylformamide; the monomer of the amidine system is selected from at least one of N-amidinododecyl acrylamide and N'-acryloyl-N,N-dimethylethylamidine; the monomer of the tertiary amino system is selected from at least one of diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and N,N-dimethylphenylene glycol; and the monomer of the nitrogen-containing azole heterocyclic system is selected from at least one of 3(1H-imidazole-4-yl)methyl acrylate and imidazoleethyl methacrylate.

3. The use according to claim 2, characterized in that The monomer of the primary amino system is selected from allylamine, the monomer of the amidine system is selected from N-amidinododecyl acrylamide, the monomer of the tertiary amino system is selected from diethylaminoethyl methacrylate, and the monomer of the nitrogen-containing azole heterocyclic system is selected from 3(1H-imidazole-4-yl)methyl acrylate.

4. The use according to claim 1, characterized in that The sponge is selected from polyurethane sponge, melamine sponge, carbon sponge or polyether sponge.

5. The use according to claim 1, characterized in that The mass ratio of the base sponge to the CO2 responsive polymer is 1:200-1:

50.

6. The use according to claim 1, characterized in that The mass ratio of the 2-bromoisobutyryl bromide to the sponge is 2:1-7.5:1, and the mass ratio of the dopamine to the sponge is 1:1-5:

1.

7. The use according to claim 1, characterized in that The concentration of the surfactant in the wastewater is 10-1000 mg / L.

8. The use according to claim 1, characterized in that The adsorption process is carried out in a shaking table with a shaking speed of 200-300 rpm and an adsorption time of 0.5-2 h.

9. The use according to claim 1, characterized in that Relative to 10 mg of CO2 responsive adsorption material, the CO2 purge gas flow rate is 100-300 mL / min, and the purge time is 2-30 min.

10. The use according to claim 1, characterized in that In step (1), the concentration of the tris(hydroxymethyl)aminomethane buffer solution is 2-10 mmol / L, and the pH value is 8.0-9.

0.

11. The use according to claim 1, characterized in that In step (1), the polymerization reaction is carried out in a shaker with a rotation speed of 150-300 rpm, a polymerization time of 10-60 min, a pressure of normal pressure, and a temperature of 25-40°C.

12. The use according to claim 1, characterized in that In step (2), the acid binding agent is selected from triethylamine, diisopropylethylamine or a mixture of triethylamine and magnesium chloride, wherein the molar ratio of TEA:MgCl2 in the mixture of triethylamine and magnesium chloride is 1.2:1-2:

1.

13. The use according to claim 1, characterized in that The molar ratio of 2-bromoisobutyryl bromide to the acid binding agent in step (2) is 1:1-1.2:

1.

14. The use according to claim 1, characterized in that In step (2), in the method for preparing the BiBB-grafted dopamine-coated sponge, after the reaction, the sponge is first washed with ultrapure water and / or ethanol, and then placed in a mixed solvent of low-carbon alcohol and water, wherein the volume ratio of low-carbon alcohol to water in the mixed solvent is 1:1-2:

1.

15. The use according to claim 1, characterized in that In step (3), the complexing agent is selected from at least one of bipyridine, tris-(2-pyridylmethyl)amine or pentamethyldiethylenetriamine, the catalyst is selected from at least one of copper chloride, copper bromide or ferric chloride, and the reducing agent is selected from at least one of ascorbic acid, stannous octoate or glucose.

16. The use according to claim 1, characterized in that In step (3), the mass ratio of the CO2 responsive monomer to the mixed solvent is 1:2-1:15, the molar ratio of the CO2 responsive monomer to the complexing agent is 200:1-50:1, the molar ratio of the CO2 responsive monomer to the catalyst is 1000:1-500:1, and the molar ratio of the catalyst to the reducing agent is 1:20-1:

65.

17. The use according to claim 1, characterized in that In step (3), the polymerization reaction time is 3-18 hours, the pressure is normal pressure, and the temperature is 25-60°C.

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