Improved phosphate adsorbents based on thiol click chemistry and methods of making the same
An improved phosphate adsorbent prepared through mercapto click chemistry and imprinting modification solves the trade-off between selectivity and regenerability in existing technologies, achieving efficient phosphate adsorption and regeneration in complex environments, and is suitable for phosphorus removal from water bodies.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI JIAOTONG UNIV
- Filing Date
- 2025-01-17
- Publication Date
- 2026-07-17
AI Technical Summary
Existing phosphate adsorbents present a trade-off between high selectivity and high regenerability, and their preparation process is complex, with hydrophobic products that are not conducive to phosphate adsorption.
Improved phosphate adsorbents were prepared using mercapto click chemistry. By modifying chitosan and functionalizing arginine, combined with aerogel crosslinking and imprinting modification, aerogel adsorbents with smooth surfaces and abundant micropores were prepared, achieving spatial restructuring of arginine.
It maintains excellent phosphate selectivity and regenerability in severely disturbed environments. The positive charge on the adsorbent surface is stable in the pH range of 3-11. Multiple hydrogen bonds and shape sieving work synergistically to improve selectivity. The regeneration rate reaches 98.15% after 10 cycles.
Smart Images
Figure CN122399751A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a technology in the field of adsorbents, specifically an improved phosphate adsorbent based on mercapto click chemistry with a selectivity coefficient of 10-90 and a regeneration rate of 98.15%, and its preparation method. Background Technology
[0002] Adsorption technology is one of the most effective methods for deep phosphorus removal from water bodies. However, current phosphate adsorbents face a trade-off between high selectivity and high regenerability. Furthermore, existing high-performance adsorbent preparation technologies typically require complex organic synthesis processes and yield hydrophobic products, which complicates phosphate adsorption. Summary of the Invention
[0003] To address the aforementioned shortcomings of existing technologies, this invention proposes an improved phosphate adsorbent based on mercapto click chemistry and its preparation method. By using click chemistry to link functional monomers, and then using phosphate as a template, an aerogel adsorbent is obtained through imprinting modification. This adsorbent can achieve excellent selective phosphate adsorption in severely disturbed aquatic environments, and the phosphate adsorption capacity remains essentially unchanged after multiple cycles, which is expected to achieve large-scale and sustainable phosphorus removal from water bodies.
[0004] This invention is achieved through the following technical solution:
[0005] This invention relates to a method for preparing an improved phosphate adsorbent based on mercapto click chemistry. The method uses modified chitosan and modified arginine, which are respectively modified by silane coupling agent, as raw materials. After obtaining arginine-functionalized chitosan particles through click chemistry reaction, glutaraldehyde is used as a crosslinking agent and phosphate is used as a template. During the aerogel crosslinking process, imprinting modification is combined to realize the spatial structure recombination of arginine and prepare an aerogel adsorbent.
[0006] The silane coupling agent modification treatment refers to: dispersing chitosan or arginine in anhydrous ethanol, adding mercaptopropyltrimethoxysilane or vinyltrimethoxysilane and refluxing and heating to obtain modified chitosan or modified arginine.
[0007] The click chemistry reaction refers to the following: modified chitosan and modified arginine are added to anhydrous ethanol and reacted with azobisisobutyronitrile under reflux heating to obtain arginine-functionalized chitosan particles.
[0008] The aforementioned arginine spatial structure recombination specifically includes:
[0009] 1) After dissolving arginine-functionalized chitosan particles in acetic acid solution, add phosphate solution as a template and stir thoroughly to achieve template etching;
[0010] 2) Glutaraldehyde was added as a crosslinking agent to the solution obtained in step 2, and the hydrogel obtained by Chen Hua was subjected to template removal and freeze drying to obtain arginine-functionalized imprinted aerogel adsorbent.
[0011] The template removal process involves, but is not limited to, immersion in NaOH solution to remove the template until phosphorus is no longer detectable in the eluent.
[0012] This invention relates to an improved phosphate adsorbent prepared by the above method, which is a 3D aerogel with a smooth surface and a large number of micropores, and exhibits positive charge in the pH range of 3-11. Technical effect
[0013] This invention utilizes arginine grafting based on mercapto click chemistry and optimizes the spatial structure of arginine through imprinting modification. Compared to existing technologies, this invention achieves stable and abundant loading of arginine on a chitosan support; it enables the recombination of the arginine spatial structure, improving its compatibility with phosphate; and the adsorbent achieves synergistic effects of weak interactions (multiple hydrogen bonds and shape sieving), maintaining excellent phosphate selectivity and regenerability even in severely disturbed environments. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the preparation of adsorbents using click chemistry and imprinting modification in this invention;
[0015] Figure 2 This is a scanning electron microscope image of the adsorbent in this invention;
[0016] Figure 3 This is a diagram of a beaker experiment as an example.
[0017] Figure 4 This is a comparison chart of adsorption data for the adsorbents in Examples 1, 2, and 3;
[0018] Figure 5 This is a graph showing the selective adsorption data of the adsorbent under anion interference in Example 3;
[0019] Figure 6 This is a graph showing the adsorption data of the adsorbent in Example 3 under cation interference.
[0020] Figure 7 This is a graph showing the adsorption data of the adsorbent in Example 3 under the interference of humic acid;
[0021] Figure 8 This is a graph showing the regenerability data of the adsorbent in Example 3. Detailed Implementation Example 1
[0022] like Figure 1As shown, this embodiment includes the following steps:
[0023] Step 1: Disperse 2g of chitosan in 100mL of anhydrous ethanol, add 5mL of mercaptopropyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified chitosan. Disperse 2g of arginine in 100mL of anhydrous ethanol, add 5mL of vinyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified arginine. The pH of the dispersion is maintained at 8 using ammonia.
[0024] Step 2: Take 2g of the modified chitosan and modified arginine obtained in Step 1 and add them to 100mL of anhydrous ethanol in a ratio of 2:1. Then, reflux and heat with 0.02g of azobisisobutyronitrile at 80℃ for 8h to complete the click chemical reaction and obtain arginine-functionalized chitosan particles.
[0025] Step 3: Dissolve 0.2g of arginine-functionalized chitosan particles obtained in Step 2 in 10mL of 0.5wt% acetic acid solution, add 0.5mL of 2000mg / L phosphate solution as a template, and stir thoroughly for 2h to achieve template etching.
[0026] Step 4: Add 0.4 mL of glutaraldehyde as a crosslinking agent to the solution obtained in Step 3, and gelation is achieved in 3 hours. Immerse the obtained hydrogel in 0.5 M NaOH solution to remove the template until no phosphorus is detected in the eluent. After freeze-drying, the arginine-functionalized imprinted aerogel adsorbent (AFIA-2:1) is finally obtained.
[0027] The performance of AFIA-2:1 obtained in step 4 was tested using a beaker experiment, such as... Figure 3 As shown. The phosphate concentration was 2 mgP / L, the adsorbent dosage was 1 g / L, the solution pH was 7, and the adsorption time was 1 h. Figure 4 As shown, the phosphate adsorption capacity of the prepared AFIA-2:1 was 1.22 mg / g, and the removal rate of phosphate in the solution was only 61%. Arginine is the main functional group for phosphate adsorption; insufficient content reduces the number of active sites, resulting in insufficient mass transfer driving force for phosphate adsorption. Simultaneously, insufficient arginine content also affects the template etching process during imprinting modification, hindering the formation of imprinted nanopores and ultimately leading to a low phosphate adsorption capacity. Example 2
[0028] like Figure 1 As shown, this embodiment includes the following steps:
[0029] Step 1: Disperse 2g of chitosan in 100mL of anhydrous ethanol, add 5mL of mercaptopropyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified chitosan. Disperse 2g of arginine in 100mL of anhydrous ethanol, add 5mL of vinyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified arginine. The pH of the dispersion is maintained at 8 using ammonia.
[0030] Step 2: Take 2g of the modified chitosan and modified arginine obtained in Step 1 in a ratio of 1:8 and add them to 100mL of anhydrous ethanol. Then, reflux and heat with 0.02g of azobisisobutyronitrile at 80℃ for 8h to complete the click chemical reaction and obtain arginine-functionalized chitosan particles.
[0031] Step 3: Dissolve 0.2g of arginine-functionalized chitosan particles obtained in Step 2 in 10mL of 0.5wt% acetic acid solution, add 0.5mL of 2000mg / L phosphate solution as a template, and stir thoroughly for 2h to achieve template etching.
[0032] Step 4: Add 0.4 mL of glutaraldehyde as a crosslinking agent to the solution obtained in Step 3, and gelation is achieved in 3 hours. Immerse the obtained hydrogel in 0.5 M NaOH solution to remove the template until no phosphorus is detected in the eluent. After freeze-drying, the arginine-functionalized imprinted aerogel adsorbent (AFIA-1:8) is finally obtained.
[0033] The performance of AFIA-1:8 obtained in step 4 was tested using a beaker experiment, such as... Figure 3 As shown. The phosphate concentration was 2 mgP / L, the adsorbent dosage was 1 g / L, the solution pH was 7, and the adsorption time was 1 h. Figure 4 As shown, the phosphate adsorption capacity of the prepared AFIA-1:8 was 1.52 mg / g, and the removal rate of phosphate in the solution was 76%. Due to the lack of cross-linking ability, the excessive loading of arginine will hinder the cross-linking of chitosan molecules, resulting in a loose 3D structure of the aerogel or imprinted nanopores that are prone to collapse, which is not conducive to phosphate adsorption. Example 3
[0034] like Figure 1 As shown, this embodiment includes the following steps:
[0035] Step 1: Disperse 2g of chitosan in 100mL of anhydrous ethanol, add 5mL of mercaptopropyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified chitosan. Disperse 2g of arginine in 100mL of anhydrous ethanol, add 5mL of vinyltrimethoxysilane, and reflux at 80℃ for 8h to obtain modified arginine. The pH of the dispersion is maintained at 8 using ammonia.
[0036] Step 2: Take 2g of the modified chitosan and modified arginine obtained in Step 1 in a ratio of 1:6 and add them to 100mL of anhydrous ethanol. Then, reflux and heat with 0.02g of azobisisobutyronitrile at 80℃ for 8h to complete the click chemical reaction and obtain arginine-functionalized chitosan particles.
[0037] Step 3: Dissolve 0.2g of arginine-functionalized chitosan particles obtained in Step 2 in 10mL of 0.5wt% acetic acid solution, add 0.5mL of 2000mg / L phosphate solution as a template, and stir thoroughly for 2h to achieve template etching.
[0038] Step 4: Add 0.4 mL of glutaraldehyde as a crosslinking agent to the solution obtained in Step 3, and gelation is achieved in 3 hours. The resulting hydrogel is then immersed in 0.5 M NaOH solution to remove the template until no phosphorus is detected in the eluent. After freeze-drying, the arginine-functionalized imprinted aerogel adsorbent (AFIA-1:4) is finally obtained. Figure 2 As shown.
[0039] The performance of AFIA-1:4 obtained in step 4 was tested using a beaker experiment, such as... Figure 3 As shown. The phosphate concentration was 2 mgP / L, the adsorbent dosage was 1 g / L, the solution pH was 7, and the adsorption time was 1 h. Figure 4 As shown, the prepared AFIA-1:4 exhibited a phosphate adsorption capacity as high as 1.89 mg / g, achieving a phosphate removal rate of 95% in solution. An appropriate ratio of arginine and chitosan can simultaneously endow the aerogel adsorbent with a stable pore structure and abundant active sites, which is beneficial for achieving efficient phosphate adsorption. Furthermore, under high Cl- concentrations… - NO3 - SO4 2- HCO3 - Under interference, Cl - NO3 - SO4 2- The ion concentrations all included 5 mg / L, 15 mg / L, 30 mg / L, and HCO3-. - The ion concentrations were 150 mg / L, 200 mg / L, and 250 mg / L, respectively. Figure 5 As shown, the phosphate adsorption capacity of AFIA-1:4 was still greater than 1.52 mg / g, which is 80% of the initial value, and the selectivity coefficient for phosphate was as high as 10-90. This excellent selectivity is mainly attributed to the higher binding energy of arginine to phosphate, the stable binding of multiple hydrogen bonds, and the shape-sieving effect of the imprinted nanopores. Furthermore, at high Na+ ion concentrations of 5 mg / L, 15 mg / L, and 30 mg / L, the adsorption capacity was also significantly improved. + K + Ca2+ Mg 2+ Under interference, such as Figure 6 As shown, the phosphate adsorption capacity of AFIA-1:4 remained within the range of 1.88 mg / g-1.90 mg / g, essentially consistent with the initial value. Furthermore, AFIA-1:4 exhibited no adsorption effect on cations, which is attributed to the electrostatic repulsion of cations by the strong positive charge of arginine. Finally, even with interference from humic acid concentrations of 5 mg / L, 15 mg / L, and 30 mg / L, although AFIA-1:4 simultaneously adsorbed humic acid at concentrations below 0.5 mg / L, such as... Figure 7 As shown, its phosphate adsorption capacity was still greater than 1.81 mg / g, which was 96% of the initial value. This is attributed to the fact that the adsorption pathway of AFIA-1:4 for humic acid is mainly driven by the hydrophobic interaction of its nonpolar region and the electrostatic attraction of its positively charged surface, with little impact on the imprinted nanopores responsible for phosphate adsorption. The adsorbed AFIA-1:4 was placed in 100 mL of 0.5 M NaOH solution and stirred thoroughly to regenerate the adsorbent. Ten cycles were performed using the same desorption solution to enrich the phosphate. Figure 8 As shown, after 10 cycles, the phosphate adsorption capacity of AFIA-1:4 remained at 1.86 mg / g, with a regeneration rate as high as 98%, while the phosphate desorption rate reached 99%, achieving an enrichment of 18.44 mg / L in the desorption solution. This is attributed to the sequential breakage of weaker hydrogen bonds in an alkaline environment, while OH... - It readily replaces phosphate in the imprinted nanopores, and AFIA-1:4 exhibits high regenerative efficiency.
[0040] The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.
Claims
1. A method for preparing an improved phosphate adsorbent, characterized in that, Modified chitosan and modified arginine, which were respectively modified by silane coupling agent, were used as raw materials. After obtaining arginine-functionalized chitosan particles through click chemistry, glutaraldehyde was used as a crosslinking agent and phosphate as a template. During the aerogel crosslinking process, imprinting modification was combined to realize the spatial structure recombination of arginine and prepare an aerogel adsorbent.
2. The method for preparing the improved phosphate adsorbent according to claim 1, characterized in that, The silane coupling agent modification treatment refers to: dispersing chitosan or arginine in anhydrous ethanol, adding mercaptopropyltrimethoxysilane or vinyltrimethoxysilane and refluxing and heating to obtain modified chitosan or modified arginine.
3. The method for preparing the improved phosphate adsorbent according to claim 1, characterized in that, The click chemistry reaction refers to the following: modified chitosan and modified arginine are added to anhydrous ethanol and reacted with azobisisobutyronitrile under reflux heating to obtain arginine-functionalized chitosan particles.
4. The method for preparing the improved phosphate adsorbent according to claim 1, characterized in that, The aforementioned arginine spatial structure recombination specifically includes: 1) After dissolving arginine-functionalized chitosan particles in acetic acid solution, add phosphate solution as a template and stir thoroughly to achieve template etching; 2) Glutaraldehyde was added as a crosslinking agent to the solution obtained in step 2, and the hydrogel obtained by Chen Hua was subjected to template removal and freeze drying to obtain arginine-functionalized imprinted aerogel adsorbent.
5. The method for preparing the improved phosphate adsorbent according to claim 1, characterized in that, The template removal is achieved by immersing the template in a NaOH solution until no phosphorus is detected in the eluent.
6. An improved phosphate adsorbent prepared by the method according to any one of claims 1-5, characterized in that, 3D aerogels with smooth surfaces and numerous micropores consistently exhibit positive charge within a pH range of 3-11.