Modified silica gel adsorbent and preparation process thereof
By modifying the preparation process of silica gel adsorbent and combining the modification of sulfobetaine and chitosan, the problems of poor selectivity and low adsorption capacity of existing adsorbents in the treatment of complex wastewater have been solved. This has enabled the efficient co-adsorption of heavy metals, organic matter and oils, thereby improving the treatment efficiency and adsorption capacity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WEIHAI YIHUI BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-04-01
- Publication Date
- 2026-07-03
Smart Images
Figure CN122321810A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of silica gel adsorbent technology, specifically to a modified silica gel adsorbent and its preparation process. Background Technology
[0002] With the rapid development of industries such as metallurgy, electroplating, printing and dyeing, and coal chemical industry, the composition of industrial wastewater is becoming increasingly complex. It commonly exhibits compound pollution characteristics, with heavy metal ions, hydrophobic organic matter, emulsified oil, and natural humic substances coexisting, posing a serious threat to the ecological environment and drinking water safety. Adsorption methods, due to their advantages of simple operation, high treatment efficiency, and no secondary pollution, are currently one of the mainstream technologies for treating compound wastewater. The performance of the core adsorbent directly determines the treatment cost and purification effect. Existing adsorbents commonly used in technology have several significant drawbacks in terms of adsorption performance: First, traditional adsorbents such as activated carbon and zeolite generally suffer from poor selectivity, low adsorption capacity, and high regeneration difficulty, resulting in poor deep treatment effects for low-concentration complex pollutants. Second, while ordinary high-porosity silica gel has advantages such as large specific surface area, controllable pore structure, and high mechanical strength, its surface only contains inert silanol groups, resulting in insufficient adsorption sites for heavy metals and organic matter. Furthermore, its excessively hydrophilic surface makes it prone to pore blockage by oil, humic substances, and other pollutants in oily wastewater treatment. Existing modified silica gels often employ single-functional group grafting modification, such as grafting only amino or thiol groups, which can only adsorb single heavy metal pollutants and cannot simultaneously remove multiple components such as oil and organic matter in complex wastewater, thus failing to meet the treatment requirements of high-concentration wastewater. Therefore, developing a modified silica gel adsorbent with both multi-pollutant co-adsorption capacity and high adsorption capacity is of significant application value for improving the treatment efficiency of industrial complex wastewater and reducing operating costs. Summary of the Invention
[0003] To address the shortcomings of existing technologies, this invention provides a modified silica gel adsorbent and its preparation process. This improves the co-adsorption capacity and overall adsorption capacity of the silica gel for multiple pollutants.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a preparation process for a modified silica gel adsorbent, comprising the following steps: adding 100-120 mL of an aqueous acetic acid solution with a mass fraction of 0.8%-1.2% and 1.2-1.8 g of modified amphiphilic chitosan to a reaction flask, stirring to dissolve, adding 4.5-5.5 g of sulfobetaine-modified silica gel, heating to 38-42℃, stirring and dispersing for 30-50 min, adding 0.06-0.08 g of epichlorohydrin crosslinking agent dropwise, and after the addition is complete, heating to 62-70℃ and reacting for 2-3 h, after the reaction is complete, adjusting the pH value to 8.0-8.5 with a sodium hydroxide solution with a mass fraction of 3.8%-4.2%, continuing to stir for 30-50 min, allowing to stand and age for 1.5-2 h, filtering, washing and vacuum drying to obtain the modified silica gel adsorbent.
[0005] Preferably, the sulfobetaine-modified silica gel is prepared by the following steps: (1) Add 20-30 mL of anhydrous methanol solvent and 3-3.4 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 20-30 min, melt 1.4-1.5 g of 1,3-propanesulfonyl lactone in a water bath at 40-45 °C, and add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask. During the dropwise addition, control the temperature in the cold water bath at 30-35 °C. After the dropwise addition is complete, keep the nitrogen protection and raise the temperature to 58-64 °C for 10-12 h. After the reaction is complete, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent. (2) Place 8.5-9.5g of silica gel in a muffle furnace and dry it at 120-130℃ for 3-4h. After cooling to room temperature, activate silica gel is obtained. Add 50-70mL of anhydrous toluene solvent and activated silica gel to the reaction flask, disperse it by ultrasonication for 30-40min, and purge with nitrogen for 10-15min. Dissolve 0.6-1.4g of sulfobetaine-modified silane coupling agent in 5-10mL of anhydrous toluene solvent, add 0.2-0.4mL of deionized water, and stir for 10-15min to obtain a hydrolyzed silane solution. Add the hydrolyzed silane solution dropwise to the reaction flask over a period of 4-8min. After the addition is complete, keep the nitrogen protection and heat to 105-115℃ for 6-8h. After the reaction is complete, filter and separate the silica gel, extract it by reflux with anhydrous ethanol, and dry it under vacuum to obtain sulfobetaine-modified silica gel.
[0006] Preferably, the addition time of the melted 1,3-propanesulfonyl lactone in step (1) is 25-30 min.
[0007] Preferably, the specific surface area of the silica gel in step (2) is 600-700 m² / g.
[0008] Preferably, the modified amphiphilic chitosan is prepared by the following steps: S1. Add 30-40 mL of anhydrous tetrahydrofuran solvent, 1-1.3 g of allyl thiourea, 1.7-1.9 g of 1-decyl mercaptan, and 0.01-0.014 g of photoinitiator to a reaction flask, stir to dissolve, purge with nitrogen for 10-15 min, place the reaction flask under a 365 nm UV lamp, and react at 20-30 °C for 0.5-1 h. After the reaction is complete, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1. S2. Add 100-120 mL of 2%-2.5% aqueous acetic acid solution and 1.9-2.2 g of chitosan to the reaction flask, stir to dissolve, add 1.55-1.65 g of intermediate 1, stir to mix, adjust the pH value to 5.0-5.5 with 3.8%-4.2% sodium hydroxide solution, and continue to add 2.8-3.2 g of formaldehyde solution dropwise. After the addition is complete, raise the temperature to 52-60℃ and react for 3.5-4.5 h. After the reaction is completed, adjust the pH value to 8.0-8.5 with 3.8%-4.2% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan.
[0009] Preferably, the photoinitiator in S1 is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.
[0010] Preferably, the formaldehyde solution in S2 has a mass fraction of 36%-38%.
[0011] This invention provides a modified silica adsorbent prepared using the modified silica adsorbent preparation process described above.
[0012] In summary, this application includes at least one of the following beneficial technical effects: This invention employs a process combining coprecipitation loading and covalent crosslinking. Sulfobetaine-modified silica gel is dispersed in modified amphiphilic chitosan, and then a covalent bridge is formed between the modified amphiphilic chitosan and the sulfobetaine-modified silica gel using an epichlorohydrin crosslinking agent. Subsequently, the pH value is adjusted to allow the modified amphiphilic chitosan to precipitate in situ and be uniformly loaded onto the inner and outer surfaces of the silica gel. After washing and drying, the modified silica gel adsorbent is obtained.
[0013] The molecular structure of sulfobetaine contains both quaternary ammonium cations and sulfonate anions. It can rapidly adsorb heavy metal cations through electrostatic attraction and ion exchange at the anionic sites. The zwitterionic structure can form a dense hydration layer on the surface of silica gel materials, resisting the non-specific adsorption of non-target pollutants such as humic substances and suspended impurities, avoiding pore blockage, ensuring the utilization rate of effective adsorption sites, and improving adsorption capacity. The long carbon chain can specifically bind to hydrophobic organic matter and emulsified oil droplets in wastewater through hydrophobic interactions and van der Waals forces. It is the core functional unit for silica gel adsorbents to achieve "amphiphilic" properties and simultaneously treat organic and oil pollutants. The thiourea structure can form stable coordination covalent bonds with heavy metal ions, improving the adsorption performance of silica gel adsorbents. The three types of groups are evenly distributed inside and outside the silica gel channels and on the surface of the chitosan-supported layer through covalent grafting. When encountering complex wastewater with multiple components, heavy metals, organic matter, and oils can bind to their corresponding sites respectively, avoiding the problem of competitive adsorption leading to a decrease in the adsorption capacity of a single component. Attached Figure Description
[0014] Figure 1 It is the synthetic reaction formula for sulfobetaine-modified silica gel.
[0015] Figure 2 It is the synthetic reaction formula for modified amphiphilic chitosan. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.
[0018] Example 1 (1) Add 20 mL of anhydrous methanol solvent and 3 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 20 min, melt 1.4 g of 1,3-propanesulfonyl lactone in a 40 °C water bath, add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask for 25 min, keep the temperature of the cold water bath at 30 °C during the dropwise addition, keep the nitrogen protection, raise the temperature to 58 °C and react for 10 h, after the reaction is completed, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent; (2) 8.5 g of silica gel with a specific surface area of 600 m² / g was placed in a muffle furnace and dried at 120 °C for 3 h. After cooling to room temperature, activated silica gel was obtained. 50 mL of anhydrous toluene solvent and activated silica gel were added to the reaction flask, and the mixture was ultrasonically dispersed for 30 min. Nitrogen gas was introduced for 10 min. 0.6 g of sulfobetaine-modified silane coupling agent was dissolved in 5 mL of anhydrous toluene solvent, and 0.2 mL of deionized water was added. The mixture was stirred for 10 min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the reaction flask over a period of 4 min. After the addition was complete, nitrogen gas was maintained, and the temperature was raised to 105 °C for 6 h. After the reaction was completed, the mixture was filtered and separated. It was then extracted by reflux with anhydrous ethanol and dried under vacuum to obtain sulfobetaine-modified silica gel. The synthesis reaction formula is as follows: Figure 1 As shown; (3) Add 30 mL of anhydrous tetrahydrofuran solvent, 1 g of allyl thiourea, 1.7 g of 1-decyl mercaptan, and 0.01 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator to the reaction flask, stir to dissolve, purge with nitrogen for 10 min, place the reaction flask under a 365 nm UV lamp, and react at 20 °C for 0.5 h. After the reaction is completed, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1; (4) Add 100 mL of 2% acetic acid aqueous solution and 1.9 g of chitosan to the reaction flask, stir to dissolve, add 1.55 g of intermediate 1, stir to mix, adjust the pH value to 5.0 with 3.8% sodium hydroxide solution, and continue to add 2.8 g of 36% formaldehyde solution dropwise. After the addition is complete, raise the temperature to 52℃ and react for 3.5 h. After the reaction is completed, adjust the pH value to 8.0 with 3.8% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan; the synthesis reaction formula is as follows. Figure 2 As shown; (5) Add 100 mL of 0.8% acetic acid aqueous solution and 1.2 g of modified amphiphilic chitosan to the reaction flask, stir to dissolve, add 4.5 g of sulfobetaine-modified silica gel, heat to 38°C, stir and disperse for 30 min, add 0.06 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 62°C and react for 2 h. After the reaction is complete, adjust the pH value to 8.0 with 3.8% sodium hydroxide solution, continue stirring for 30 min, let stand and age for 1.5 h, filter, wash and vacuum dry to obtain modified silica gel adsorbent.
[0019] Example 2 (1) Add 30 mL of anhydrous methanol solvent and 3.4 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 30 min, melt 1.5 g of 1,3-propanesulfonyl lactone in a 45 °C water bath, add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask over 30 min, keep the temperature of the cold water bath at 35 °C during the dropwise addition, keep the nitrogen protection, raise the temperature to 64 °C and react for 12 h, after the reaction is completed, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent; (2) 9.5 g of silica gel with a specific surface area of 700 m² / g was placed in a muffle furnace and dried at 130 °C for 4 h. After cooling to room temperature, activated silica gel was obtained. 70 mL of anhydrous toluene solvent and activated silica gel were added to the reaction flask, and the mixture was ultrasonically dispersed for 40 min. Nitrogen gas was introduced for 15 min. 1.4 g of sulfobetaine-modified silane coupling agent was dissolved in 10 mL of anhydrous toluene solvent, and 0.4 mL of deionized water was added. The mixture was stirred for 15 min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the reaction flask over 8 min. After the addition was complete, nitrogen protection was maintained, and the temperature was raised to 115 °C for 8 h. After the reaction was completed, the mixture was filtered and separated, extracted by reflux with anhydrous ethanol, and dried under vacuum to obtain sulfobetaine-modified silica gel. The synthesis reaction formula is as follows: Figure 1 As shown; (3) Add 40 mL of anhydrous tetrahydrofuran solvent, 1.3 g of allyl thiourea, 1.9 g of 1-decyl mercaptan, and 0.014 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator to the reaction flask, stir to dissolve, purge with nitrogen for 15 min, place the reaction flask under a 365 nm ultraviolet lamp, and react at 30 °C for 1 h. After the reaction is completed, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1; (4) Add 120 mL of 2.5% acetic acid aqueous solution and 2.2 g of chitosan to the reaction flask, stir to dissolve, add 1.65 g of intermediate 1, stir to mix, adjust the pH value to 5.5 with 4.2% sodium hydroxide solution, and continue to add 3.2 g of 38% formaldehyde solution dropwise. After the addition is complete, heat to 60℃ and react for 4.5 h. After the reaction is completed, adjust the pH value to 8.5 with 4.2% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan; the synthesis reaction formula is as follows. Figure 2 As shown; (5) Add 120 mL of 1.2% acetic acid aqueous solution and 1.8 g of modified amphiphilic chitosan to the reaction flask, stir to dissolve, add 5.5 g of sulfobetaine-modified silica gel, heat to 42 °C, stir and disperse for 50 min, add 0.08 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 70 °C and react for 3 h. After the reaction is complete, adjust the pH value to 8.5 with 4.2% sodium hydroxide solution, continue stirring for 50 min, let stand and age for 2 h, filter, wash and vacuum dry to obtain modified silica gel adsorbent.
[0020] Example 3 (1) Add 25 mL of anhydrous methanol solvent and 3.2 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 25 min, melt 1.45 g of 1,3-propanesulfonyl lactone in a 42 °C water bath, add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask over a period of 28 min, keep the temperature of the cold water bath at 32 °C during the dropwise addition, keep the nitrogen protection, raise the temperature to 61 °C and react for 11 h, after the reaction is completed, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent; (2) 9g of silica gel with a specific surface area of 650m² / g was placed in a muffle furnace and dried at 125℃ for 3.5h. After cooling to room temperature, activated silica gel was obtained. 60mL of anhydrous toluene solvent and activated silica gel were added to the reaction flask, and ultrasonically dispersed for 35min. Nitrogen gas was introduced for 12min. 1g of sulfobetaine-modified silane coupling agent was dissolved in 7.5mL of anhydrous toluene solvent, and 0.3mL of deionized water was added. The mixture was stirred for 12min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the reaction flask over a period of 6min. After the addition was complete, nitrogen protection was maintained, and the temperature was raised to 110℃ for 7h. After the reaction was completed, the mixture was filtered and separated, extracted by reflux with anhydrous ethanol, and dried under vacuum to obtain sulfobetaine-modified silica gel. The synthesis reaction formula is as follows: Figure 1 As shown; (3) Add 35 mL of anhydrous tetrahydrofuran solvent, 1.15 g of allyl thiourea, 1.8 g of 1-decyl mercaptan, and 0.012 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator to the reaction flask, stir to dissolve, purge with nitrogen for 12 min, place the reaction flask under a 365 nm ultraviolet lamp, and react at 25 °C for 0.8 h. After the reaction is completed, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1; (4) Add 110 mL of 2.2% acetic acid aqueous solution and 2.05 g of chitosan to the reaction flask, stir to dissolve, add 1.6 g of intermediate 1, stir to mix, adjust the pH value to 5.2 with 4% sodium hydroxide solution, and continue to add 3 g of 37% formaldehyde solution dropwise. After the addition is complete, raise the temperature to 56℃ and react for 4 h. After the reaction is completed, adjust the pH value to 8.2 with 4% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan; the synthesis reaction formula is as follows. Figure 2 As shown; (5) Add 110 mL of 1% acetic acid aqueous solution and 1.5 g of modified amphiphilic chitosan to the reaction flask, stir to dissolve, add 5 g of sulfobetaine-modified silica gel, heat to 40 °C, stir and disperse for 40 min, add 0.07 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 66 °C and react for 2.5 h. After the reaction is complete, adjust the pH value to 8.3 with 4% sodium hydroxide solution, continue stirring for 40 min, let stand and age for 1.8 h, filter, wash and vacuum dry to obtain modified silica gel adsorbent.
[0021] Example 4 (1) Add 20 mL of anhydrous methanol solvent and 3 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 20 min, melt 1.4 g of 1,3-propanesulfonyl lactone in a 40 °C water bath, add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask for 25 min, keep the temperature of the cold water bath at 30 °C during the dropwise addition, keep the nitrogen protection, raise the temperature to 58 °C and react for 10 h, after the reaction is completed, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent; (2) 8.5 g of silica gel with a specific surface area of 600 m² / g was placed in a muffle furnace and dried at 120 °C for 3 h. After cooling to room temperature, activated silica gel was obtained. 50 mL of anhydrous toluene solvent and activated silica gel were added to the reaction flask, and the mixture was ultrasonically dispersed for 30 min. Nitrogen gas was introduced for 10 min. 0.6 g of sulfobetaine-modified silane coupling agent was dissolved in 5 mL of anhydrous toluene solvent, and 0.2 mL of deionized water was added. The mixture was stirred for 10 min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the reaction flask over a period of 4 min. After the addition was complete, nitrogen gas was maintained, and the temperature was raised to 105 °C for 6 h. After the reaction was completed, the mixture was filtered and separated. It was then extracted by reflux with anhydrous ethanol and dried under vacuum to obtain sulfobetaine-modified silica gel. The synthesis reaction formula is as follows: Figure 1 As shown; (3) Add 40 mL of anhydrous tetrahydrofuran solvent, 1.3 g of allyl thiourea, 1.9 g of 1-decyl mercaptan, and 0.014 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator to the reaction flask, stir to dissolve, purge with nitrogen for 15 min, place the reaction flask under a 365 nm ultraviolet lamp, and react at 30 °C for 1 h. After the reaction is completed, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1; (4) Add 120 mL of 2.5% acetic acid aqueous solution and 2.2 g of chitosan to the reaction flask, stir to dissolve, add 1.65 g of intermediate 1, stir to mix, adjust the pH value to 5.5 with 4.2% sodium hydroxide solution, and continue to add 3.2 g of 38% formaldehyde solution dropwise. After the addition is complete, heat to 60℃ and react for 4.5 h. After the reaction is completed, adjust the pH value to 8.5 with 4.2% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan; the synthesis reaction formula is as follows. Figure 2 As shown; (5) Add 110 mL of 1% acetic acid aqueous solution and 1.5 g of modified amphiphilic chitosan to the reaction flask, stir to dissolve, add 5 g of sulfobetaine-modified silica gel, heat to 40 °C, stir and disperse for 40 min, add 0.07 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 66 °C and react for 2.5 h. After the reaction is complete, adjust the pH value to 8.3 with 4% sodium hydroxide solution, continue stirring for 40 min, let stand and age for 1.8 h, filter, wash and vacuum dry to obtain modified silica gel adsorbent.
[0022] Example 5 (1) Add 25 mL of anhydrous methanol solvent and 3.2 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 25 min, melt 1.45 g of 1,3-propanesulfonyl lactone in a 42 °C water bath, add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask over a period of 28 min, keep the temperature of the cold water bath at 32 °C during the dropwise addition, keep the nitrogen protection, raise the temperature to 61 °C and react for 11 h, after the reaction is completed, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent; (2) 9g of silica gel with a specific surface area of 650m² / g was placed in a muffle furnace and dried at 125℃ for 3.5h. After cooling to room temperature, activated silica gel was obtained. 60mL of anhydrous toluene solvent and activated silica gel were added to the reaction flask, and ultrasonically dispersed for 35min. Nitrogen gas was introduced for 12min. 1g of sulfobetaine-modified silane coupling agent was dissolved in 7.5mL of anhydrous toluene solvent, and 0.3mL of deionized water was added. The mixture was stirred for 12min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the reaction flask over a period of 6min. After the addition was complete, nitrogen protection was maintained, and the temperature was raised to 110℃ for 7h. After the reaction was completed, the mixture was filtered and separated, extracted by reflux with anhydrous ethanol, and dried under vacuum to obtain sulfobetaine-modified silica gel. The synthesis reaction formula is as follows: Figure 1 As shown; (3) Add 30 mL of anhydrous tetrahydrofuran solvent, 1 g of allyl thiourea, 1.7 g of 1-decyl mercaptan, and 0.01 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone photoinitiator to the reaction flask, stir to dissolve, purge with nitrogen for 10 min, place the reaction flask under a 365 nm UV lamp, and react at 20 °C for 0.5 h. After the reaction is completed, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1; (4) Add 100 mL of 2% acetic acid aqueous solution and 1.9 g of chitosan to the reaction flask, stir to dissolve, add 1.55 g of intermediate 1, stir to mix, adjust the pH value to 5.0 with 3.8% sodium hydroxide solution, and continue to add 2.8 g of 36% formaldehyde solution dropwise. After the addition is complete, raise the temperature to 52℃ and react for 3.5 h. After the reaction is completed, adjust the pH value to 8.0 with 3.8% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan; the synthesis reaction formula is as follows. Figure 2 As shown; (5) Add 120 mL of 1.2% acetic acid aqueous solution and 1.8 g of modified amphiphilic chitosan to the reaction flask, stir to dissolve, add 5.5 g of sulfobetaine-modified silica gel, heat to 42 °C, stir and disperse for 50 min, add 0.08 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 70 °C and react for 3 h. After the reaction is complete, adjust the pH value to 8.5 with 4.2% sodium hydroxide solution, continue stirring for 50 min, let stand and age for 2 h, filter, wash and vacuum dry to obtain modified silica gel adsorbent.
[0023] Comparative Example 1 The difference between this comparative example and Example 5 is that it does not include step (1), and in step (2) N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane is used instead of sulfobetaine-modified silane coupling agent.
[0024] Comparative Example 2 The difference between this comparative example and Example 5 is that it does not include steps (3) and (4), and in step (5) chitosan is used instead of modified amphiphilic chitosan.
[0025] Based on the water quality characteristics of typical mixed industrial wastewater from metallurgy and coal chemical industries, three groups of simulated composite wastewater with different concentration gradients were prepared. The specific components are shown in Table 1.
[0026] Table 1: Components of Simulated Composite Wastewater
[0027] Emulsified oil preparation method: Mix 0# diesel oil and Tween 80 at a mass ratio of 10:1, add deionized water, and emulsify at high speed for 30 minutes to obtain a stable milky white emulsified oil stock solution, which can then be diluted to the target concentration.
[0028] 100 mL of each of the three simulated wastewater samples was placed in a 250 mL Erlenmeyer flask. 0.05 g of modified silica gel adsorbent was added at a solid-liquid ratio of 0.5 g / L. The flasks were sealed and placed in a constant-temperature shaking incubator at 25℃ and 200 rpm for 18 hours until adsorption equilibrium was reached. After adsorption, the residual concentrations of the three pollutants were measured, and the equilibrium adsorption capacity was calculated. The test results are shown in Tables 2, 3, and 4.
[0029] Table 2: Hg² + Equilibrium adsorption capacity:
[0030] Table 3: Equilibrium adsorption capacity of bisphenol A:
[0031] Table 4: Equilibrium Adsorption Capacity of Emulsified Oil
[0032] As shown in Tables 2, 3, and 4, the modified silica gel adsorbents in Examples 1-5 of the present invention have higher co-adsorption capacity and adsorption capacity for multiple pollutants in industrial composite wastewater compared with the modified silica gel adsorbents in Comparative Examples 1-2.
[0033] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
[0035] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.
Claims
1. A preparation process for a modified silica gel adsorbent, characterized in that, The process includes the following steps: Add 100-120 mL of 0.8%-1.2% aqueous acetic acid solution and 1.2-1.8 g of modified amphiphilic chitosan to a reaction flask, stir to dissolve, add 4.5-5.5 g of sulfobetaine-modified silica gel, heat to 38-42℃, stir and disperse for 30-50 min, add 0.06-0.08 g of epichlorohydrin crosslinking agent dropwise, after the addition is complete, heat to 62-70℃ and react for 2-3 h. After the reaction is complete, adjust the pH to 8.0-8.5 with 3.8%-4.2% sodium hydroxide solution, continue stirring for 30-50 min, let stand and age for 1.5-2 h, filter, wash and vacuum dry to obtain the modified silica gel adsorbent.
2. The preparation process of the modified silica gel adsorbent according to claim 1, characterized in that, The sulfobetaine-modified silica gel is prepared by the following steps: (1) Add 20-30 mL of anhydrous methanol solvent and 3-3.4 g of N-(hydroxyethyl)-N-methylaminopropyltrimethoxysilane to the reaction flask, purge with nitrogen for 20-30 min, melt 1.4-1.5 g of 1,3-propanesulfonyl lactone in a water bath at 40-45 °C, and add the melted 1,3-propanesulfonyl lactone dropwise to the reaction flask. During the dropwise addition, control the temperature in the cold water bath at 30-35 °C. After the dropwise addition is complete, keep the nitrogen protection and raise the temperature to 58-64 °C for 10-12 h. After the reaction is complete, distill under reduced pressure, add anhydrous diethyl ether solvent, let stand for layering, pour off the supernatant, wash and centrifuge, and vacuum dry to obtain sulfobetaine-modified silane coupling agent. (2) Place 8.5-9.5g of silica gel in a muffle furnace and dry it at 120-130℃ for 3-4h. After cooling to room temperature, activate silica gel is obtained. Add 50-70mL of anhydrous toluene solvent and activated silica gel to the reaction flask, disperse it by ultrasonication for 30-40min, and purge with nitrogen for 10-15min. Dissolve 0.6-1.4g of sulfobetaine-modified silane coupling agent in 5-10mL of anhydrous toluene solvent, add 0.2-0.4mL of deionized water, and stir for 10-15min to obtain a hydrolyzed silane solution. Add the hydrolyzed silane solution dropwise to the reaction flask over a period of 4-8min. After the addition is complete, keep the nitrogen protection and heat to 105-115℃ for 6-8h. After the reaction is complete, filter and separate the silica gel, extract it by reflux with anhydrous ethanol, and dry it under vacuum to obtain sulfobetaine-modified silica gel.
3. The preparation process of the modified silica gel adsorbent according to claim 2, characterized in that, The addition time of the melted 1,3-propanesulfonyl lactone in step (1) is 25-30 min.
4. The preparation process of the modified silica gel adsorbent according to claim 2, characterized in that, The specific surface area of the silica gel in step (2) is 600-700 m² / g.
5. The preparation process of the modified silica gel adsorbent according to claim 1, characterized in that, The modified amphiphilic chitosan was prepared through the following steps: S1. Add 30-40 mL of anhydrous tetrahydrofuran solvent, 1-1.3 g of allyl thiourea, 1.7-1.9 g of 1-decyl mercaptan, and 0.01-0.014 g of photoinitiator to a reaction flask, stir to dissolve, purge with nitrogen for 10-15 min, place the reaction flask under a 365 nm UV lamp, and react at 20-30 °C for 0.5-1 h. After the reaction is complete, remove the solvent by vacuum distillation, wash and vacuum dry to obtain intermediate 1. S2. Add 100-120 mL of 2%-2.5% aqueous acetic acid solution and 1.9-2.2 g of chitosan to the reaction flask, stir to dissolve, add 1.55-1.65 g of intermediate 1, stir to mix, adjust the pH value to 5.0-5.5 with 3.8%-4.2% sodium hydroxide solution, and continue to add 2.8-3.2 g of formaldehyde solution dropwise. After the addition is complete, raise the temperature to 52-60℃ and react for 3.5-4.5 h. After the reaction is completed, adjust the pH value to 8.0-8.5 with 3.8%-4.2% sodium hydroxide solution, wash and freeze dry to obtain modified amphiphilic chitosan.
6. The preparation process of the modified silica gel adsorbent according to claim 5, characterized in that, The photoinitiator in S1 is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.
7. The preparation process of the modified silica gel adsorbent according to claim 5, characterized in that, The formaldehyde solution in S2 has a mass fraction of 36%-38%.
8. A modified silica adsorbent prepared using the preparation process of the modified silica adsorbent as described in any one of claims 1-7.