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CN-122011490-A - Porous biochar/cellulose/polyvinyl alcohol aerogel, preparation method and application thereof

CN122011490ACN 122011490 ACN122011490 ACN 122011490ACN-122011490-A

Abstract

The application provides porous biochar/cellulose/polyvinyl alcohol aerogel, a preparation method and application thereof, wherein the preparation method comprises the steps of (1) utilizing alkali to pretreat traditional Chinese medicine residues, calcining the traditional Chinese medicine residues and cysteine in a tube furnace to obtain nitrogen-sulfur doped porous biochar, (2) dissolving carboxymethyl cellulose and polyvinyl alcohol in deionized water to form uniform solution, (3) mixing the two solutions obtained in the step (2) to form mixed solution, carrying out ultrasonic treatment on the mixed solution for 10-60min, heating the mixed solution for 10-60min at 30-70 ℃, carrying out freezing treatment, then carrying out slicing treatment, and soaking slices in an acid solution with the pH value of 3-5 for 0.5-1h to obtain the porous aerogel. The preparation method of the porous aerogel is simple, green and environment-friendly, has excellent effect, and can be used for removing pollutants and desalting sea water.

Inventors

  • YU BO
  • LI XIAONING
  • YAN HAN
  • MA JIAO
  • MA JIAN
  • LIAN KE
  • ZHANG MING
  • WANG XINTAO

Assignees

  • 中铁水务集团有限公司

Dates

Publication Date
20260512
Application Date
20260127

Claims (10)

  1. 1. A method for preparing a porous aerogel, comprising the steps of: (1) Calcining the traditional Chinese medicine residues and cysteine in a tube furnace by utilizing alkali pretreatment traditional Chinese medicine residues to obtain nitrogen-sulfur doped porous biochar; (2) Respectively dissolving carboxymethyl cellulose and polyvinyl alcohol in deionized water to form a uniform solution; (3) Mixing the two solutions obtained in the step (2), adding 0.2-2wt% of the nitrogen-sulfur doped porous biochar and 0.01-0.1wt% of nano calcium carbonate to form a mixed solution, carrying out ultrasonic reaction on the mixed solution for 10-60min, then heating for 10-60min at 30-70 ℃ to form hydrogel, freezing the hydrogel, thawing the hydrogel, carrying out slicing treatment, soaking the slices in an acid solution, washing, and freeze-drying to obtain the porous aerogel.
  2. 2. The method of claim 1, wherein in the step (1), the herb residue is licorice residue and astragalus residue, and the mass ratio of the herb residue to the cysteine is (14-16): 1.
  3. 3. The method of claim 1, wherein in the step (1), the alkali is NaOH, KOH, na 2 CO 3 、K 2 CO 3 , the concentration is 0.5-1.0mol/L, and the alkali treatment time is 9-11h.
  4. 4. The method according to claim 1, wherein in the step (1), the calcination temperature is 300 to 800 ℃ and the time is 0.5 to 2 hours.
  5. 5. The method of claim 1, wherein in the step (2), the concentration of the carboxymethyl cellulose is 2-5wt% and the concentration of the polyvinyl alcohol is 5-15wt%.
  6. 6. The method according to claim 1, wherein in the step (3), the hydrogel undergoes at least one cycle of freezing, thawing and refreezing to crosslink functional groups such as carboxyl groups, hydroxyl groups and the like between cellulose, biochar and polyvinyl alcohol, and the thickness of the slice is 1.5-2.5cm.
  7. 7. The method of claim 1, wherein in the step (3), the acid solution is acetic acid or hydrochloric acid solution, the pH of the acid solution is 3-5, and the soaking time of the acid solution is 0.5-1h.
  8. 8. The porous aerogel of any of claims 1-7, wherein the porous aerogel is a porous biochar/cellulose/polyvinyl alcohol aerogel.
  9. 9. The use of a porous aerogel according to claim 8 in water treatment, comprising the steps of: (1) Removing multi-element metal ions, namely placing aerogel in a multi-element metal ion aqueous solution, stirring and adsorbing for 2-4 hours, filtering supernatant fluid after the adsorption is finished, and measuring the concentration of the residual metal ions in the aqueous solution by utilizing atomic absorption fluorescence spectroscopy; (2) And (3) water treatment, namely placing the aerogel in pure water or seawater, and performing temperature and water evaporation tests.
  10. 10. The use according to claim 9, wherein in step (1) the aqueous solution of multi-element metal ions comprises Cu, pb, zn, ni, cr metal ions in a concentration of 10-200mg/L.

Description

Porous biochar/cellulose/polyvinyl alcohol aerogel, preparation method and application thereof Technical Field The application relates to the technical field of aerogel materials, in particular to porous biochar/cellulose/polyvinyl alcohol aerogel, a preparation method and application thereof. Background With the increasing population and the continuous development of economy, the shortage of water resources has become one of the difficulties to be solved by the present-day mankind. The research finds that the seawater accounts for about 97.5% of the global water quantity, so the seawater desalination is an effective scheme for effectively relieving the shortage of water resources. In addition, the emission of a large amount of heavy metal sewage and wastewater caused by industries such as smelting, chemical industry, electroplating, electronics and the like is also one of the problems affecting the shortage of water resources. In the sewage discharge process, heavy metal wastewater can cause serious harm to the ecological environment, and once entering a human body, the nervous system and the immune system can be damaged, even cancers can be induced, and the human health is seriously threatened. Therefore, the removal of heavy metals in the heavy metal wastewater not only can reduce the continuous damage to the environment, but also is one of effective ways for relieving the shortage of water resources. Aerogel is used as a material with a three-dimensional network structure, and is widely applied to the removal of pollutants in sewage and the desalination of sea water due to the characteristics of excellent specific surface area, abundant porous structures, multiple functional groups, excellent heat insulation performance and the like. In carrying out the present application, the present inventors have found that the related art has at least the following problems: the existing aerogel synthesis process is complex and has high cost, most of the synthesis and application of the aerogel are only concentrated in the research of single functions, and the aerogel is difficult to play in the complex environment in the actual use process. Disclosure of Invention In view of the above, the application provides a porous biochar/cellulose/polyvinyl alcohol aerogel, a preparation method and application thereof, and aims to solve the problems of complex preparation process, high cost and single application of the aerogel. In order to achieve the above object, the present application provides a method for preparing porous aerogel, comprising the following steps: (1) Calcining the traditional Chinese medicine residues and cysteine in a tube furnace by utilizing alkali pretreatment traditional Chinese medicine residues to obtain nitrogen-sulfur doped porous biochar; (2) Respectively dissolving carboxymethyl cellulose and polyvinyl alcohol in deionized water to form a uniform solution; (3) Mixing the two solutions obtained in the step (2), adding 0.2-2wt% of the nitrogen-sulfur doped porous biochar and 0.01-0.1wt% of nano calcium carbonate to form a mixed solution, carrying out ultrasonic reaction on the mixed solution for 10-60min, then carrying out reaction for 10-60min at 30-70 ℃ to form hydrogel, freezing the hydrogel, thawing the hydrogel, carrying out slicing treatment, soaking the slices in an acid solution, washing, and freeze-drying to obtain the porous aerogel. In some embodiments, in the step (1), the Chinese medicine residue is licorice residue and astragalus residue, and the mass ratio of the Chinese medicine residue to the cysteine is (14-16): 1. In some embodiments, in step (1), the base is NaOH, KOH, na 2CO3、K2CO3, the concentration is 0.5-1.0mol/L, and the base treatment time is 9-11h. In some embodiments, in step (1), the calcination temperature is 300-800 ℃ for a time of 0.5-2 hours. In some embodiments, in step (2), the concentration of the carboxymethyl cellulose is 2-5wt% and the concentration of the polyvinyl alcohol is 5-15wt%. In some embodiments, in the step (3), the hydrogel undergoes at least one cycle of freezing, thawing and refreezing to crosslink functional groups such as carboxyl groups, hydroxyl groups and the like between cellulose, biochar and polyvinyl alcohol, and the thickness of the slice is 1.5-2.5cm. In some embodiments, in the step (3), the acid solution is acetic acid or hydrochloric acid solution, the pH of the acid solution is 3-5, and the acid solution soaking time is 0.5-1h. In some embodiments, any of the porous aerogels described herein is a porous biochar/cellulose/polyvinyl alcohol aerogel. In some embodiments, the use of the porous aerogel in water treatment comprises the steps of: (1) Removing multi-element metal ions, namely placing aerogel in a multi-element metal ion aqueous solution, stirring and adsorbing for 2-4 hours, filtering supernatant fluid after the adsorption is finished, and measuring the concentration of the residual metal ions in the aqueous solution b