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CN-122006667-A - Modified sodium alginate and preparation method and application thereof

CN122006667ACN 122006667 ACN122006667 ACN 122006667ACN-122006667-A

Abstract

The application relates to the technical field of adsorbents, in particular to modified sodium alginate, a preparation method and application thereof, wherein the preparation raw materials of the modified sodium alginate comprise sodium alginate, a cross-linking agent, a buffering agent, an activating agent and acidic amino acid. The modified sodium alginate can effectively adsorb and remove methylene blue in water, and can maintain good adsorption performance after repeated cyclic adsorption-desorption.

Inventors

  • YU WEI
  • Liu Longyufan
  • LIN HONGJUN
  • SHEN LIGUO
  • JI CHENGLIN
  • ZHANG XURONG
  • HE MEIJIAO
  • LIU SHUO

Assignees

  • 浙江师范大学

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The modified sodium alginate is characterized in that the preparation raw materials of the modified sodium alginate comprise sodium alginate, a cross-linking agent, a buffering agent, an activating agent and acidic amino acid.
  2. 2. A modified sodium alginate according to claim 1, wherein the acidic amino acid comprises at least one of aspartic acid or glutamic acid, and/or The mol ratio of the acidic amino acid to the sodium alginate is (1-3): 1.
  3. 3. A modified sodium alginate according to claim 1, wherein the cross-linking agent comprises anhydrous calcium chloride and/or The mole ratio of the cross-linking agent to the sodium alginate is (7-21): 1.
  4. 4. The modified sodium alginate of claim 1, wherein the activator satisfies at least one of the following conditions: (1) The activator comprises at least one of N-hydroxysuccinimide or 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride; (2) The activator comprises a combination of N-hydroxysuccinimide and 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, the molar ratio of N-hydroxysuccinimide to 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride being (0.5-1.5): 1, a step of; (3) The mol ratio of the activator to the sodium alginate is (1-4): 1.
  5. 5. A modified sodium alginate according to claim 1, wherein the buffer comprises 2-morpholinoethanesulfonic acid and/or The mol ratio of the buffer to the sodium alginate is (0.5-1.5): 1.
  6. 6. A method for preparing the modified sodium alginate as claimed in any one of claims 1 to 5, comprising the steps of: and mixing sodium alginate, a cross-linking agent, a buffering agent, an activating agent and acidic amino acid, and reacting to obtain the modified sodium alginate.
  7. 7. The preparation method according to claim 6, characterized in that the preparation method comprises the steps of: (1) Mixing sodium alginate and a solvent to obtain a sodium alginate solution; (2) Mixing a cross-linking agent with the sodium alginate solution prepared in the step (1) to perform a cross-linking reaction to obtain sodium alginate gel; (3) Freeze-drying the sodium alginate gel prepared in the step (2); (4) Mixing a buffering agent, an activating agent and the product of the step (3) to perform an activation reaction; (5) Mixing the product of the step (4) with acidic amino acid, and carrying out mediated amide reaction to obtain the modified sodium alginate.
  8. 8. The preparation method according to claim 7, wherein the preparation method satisfies at least one of the following conditions: a. in the step (2), firstly, a cross-linking agent and a solvent are mixed to obtain a cross-linking agent solution, and then the cross-linking agent solution is mixed with the sodium alginate solution prepared in the step (1) to carry out a cross-linking reaction to obtain sodium alginate gel; b. in the step (2), the time of the crosslinking reaction is 15-30min; c. in the step (3), the temperature of freeze drying is-10 to-70 ℃ and the time is 10-40 h; d. In the step (4), the buffer and the activator are mixed with the solvent independently, or the buffer and the activator are mixed with the solvent, and then the mixed solution is mixed with the product of the step (3) for activation reaction; e. in the step (4), the time of the activation reaction is 30-60min; f. in step (5), the time for mediating the amide reaction is 1 to 6 hours; g. the activation reaction described in step (4) and the mediated amide reaction described in step (5) are each independently carried out under light-protected conditions.
  9. 9. An adsorbent comprising the modified sodium alginate of any one of claims 1 to 5 or the modified sodium alginate obtained by the method of any one of claims 6 to 8.
  10. 10. Use of the adsorbent of claim 9 in water treatment.

Description

Modified sodium alginate and preparation method and application thereof Technical Field The application relates to the field of adsorbents, in particular to modified sodium alginate and a preparation method and application thereof. Background Aiming at the treatment requirement of printing and dyeing wastewater, the traditional adsorption material has the problems of high cost, low efficiency, secondary pollution and the like. Sodium alginate is used as natural polysaccharide, has the advantages of good biocompatibility, degradability, wide sources and the like, and the molecular chain of the sodium alginate is rich in carboxyl and hydroxyl, so that the sodium alginate has good affinity to metal ions in theory. However, natural sodium alginate has the defects of weak mechanical strength, limited adsorption capacity, poor selectivity and the like, and limits industrial application. The existing modification technology improves the performance to a certain extent, but still has the problems of complex preparation process, high cost, insufficient structural controllability and the like. Therefore, there is a need to develop an adsorbent having a good adsorption function. Disclosure of Invention In view of the above problems, the application provides modified sodium alginate, a preparation method and application thereof, wherein the modified sodium alginate can effectively adsorb and remove methylene blue in water, and can maintain good adsorption performance after repeated cyclic adsorption-desorption. In a first aspect, the application provides modified sodium alginate, and the preparation raw materials of the modified sodium alginate comprise sodium alginate, a cross-linking agent, a buffering agent, an activating agent and acidic amino acid. According to the technical scheme, the natural polysaccharide sodium alginate is used as a raw material, is wide in source, good in biocompatibility and degradable, accords with the environment-friendly concept, has a molecular chain rich in carboxyl and hydroxyl, can effectively adsorb heavy metal ions through chelation, ion exchange and other modes, has good film forming and balling performances, and is easy to prepare into various forms such as gel and microsphere. Compared with the traditional adsorption material, the method has lower cost and no secondary pollution risk, and provides an ideal platform for constructing a high-efficiency and economic wastewater treatment system. However, natural sodium alginate has the defects of weak mechanical strength, limited adsorption capacity, poor selectivity and the like, and limits industrial application. Based on the method, the sodium alginate and the acidic amino acid are subjected to the mediated amide reaction through the cross-linking agent, the buffering agent and the activating agent, and the characteristics that the acidic amino acid is easy to generate the amide reaction so as to be introduced onto a sodium alginate molecular chain and is rich in anionic group carboxyl are utilized, so that the obtained modified sodium alginate overcomes the defects of weak mechanical strength, limited adsorption capacity, poor selectivity and the like of natural sodium alginate, has the surface adsorption active sites increased relative to the sodium alginate, can effectively adsorb and remove methylene blue in water, has the advantage of recycling, and still maintains good adsorption performance after repeated cyclic adsorption-desorption. In some embodiments, the acidic amino acid comprises at least one of aspartic acid or glutamic acid, optionally glutamic acid, and/or The molar ratio of the acidic amino acid to the sodium alginate is (1-3): 1, wherein 1-3 can be 1, 1.1, 1.5, 1.7, 2, 2.3, 2.5, 3, etc., or the range value composed of any two of the above. According to the technical scheme of the embodiment of the application, the adsorption performance of the modified sodium alginate can be further optimized by selecting the acidic amino acid. The molar ratio of the acidic amino acid to the sodium alginate is in the range, so that the effective reaction rate between reactants can be improved, the grafting efficiency of the acidic amino acid is improved, if the acidic amino acid is excessive, the amino acid molecules can be automatically condensed, so that the grafting reaction efficiency is reduced, and if the sodium alginate is excessive, the amino supply is insufficient, so that the mediated amide reaction is incomplete. In the molar ratio of the acidic amino acid to the sodium alginate, the acidic amino acid takes the molecular weight of the amino acid as a calculation reference, and the sodium alginate gel takes a sodium alginate molecular chain repeating unit (C 6H7O6 Na) with the molecular weight of 198 as a calculation reference. In some embodiments, the crosslinking agent comprises anhydrous calcium chloride, and/or The molar ratio of the cross-linking agent to the sodium alginate is (7-21): 1, wherein 7-21 can be 7, 10