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CN-121974466-A - Choline ionic liquid modified soybean protein flocculant and preparation method and application thereof

CN121974466ACN 121974466 ACN121974466 ACN 121974466ACN-121974466-A

Abstract

The invention relates to the technical field of water treatment, and discloses a choline ionic liquid modified soybean protein flocculant, a preparation method and application thereof. The flocculant is prepared by grafting a methacryloxyethylcholine chloride monomer on a soy protein framework under the initiation of a redox system. The flocculant has high charge neutralization capability, excellent biodegradability and antibacterial activity, is suitable for purifying domestic sewage, algae-containing wastewater and drinking water, and is eco-friendly.

Inventors

  • XU SHANLIN
  • SHI JUNQIANG
  • SUN HONGLEI
  • WU LIJUN
  • Zhu Pinyue
  • WU ZHENTAO

Assignees

  • 浙江工业大学

Dates

Publication Date
20260505
Application Date
20260403

Claims (10)

  1. 1. The preparation method of the choline ionic liquid modified soybean protein flocculant is characterized by comprising the following steps of: S1, regulating the pH value of a soy protein isolate aqueous solution to 8.5-10.5, stirring at 40-50 ℃, introducing nitrogen to drive oxygen for at least 20 minutes, and inducing protein subunits to be unfolded; s2, under the protection of nitrogen, adding a redox initiator into the system obtained in the step S1, and then adding a solution of a methacryloyloxyethyl choline chloride monomer to perform graft copolymerization reaction; S3, adding a buffer solution into the reaction system obtained in the step S2 to adjust the pH to 6.5-7.5, and standing and aging for 2-4 hours at room temperature after terminating the reaction; And S4, carrying out precipitation washing on the aged product in the step S3 by using absolute ethyl alcohol, and then carrying out freeze drying to obtain the choline ionic liquid modified soybean protein flocculant.
  2. 2. The method according to claim 1, wherein in step S1, the mass concentration of the isolated soy protein solution is 30 g/L to 45 g/L.
  3. 3. The method according to claim 1, wherein in step S1, one or more of sodium hydroxide, potassium hydroxide or sodium carbonate is used to adjust pH.
  4. 4. The method according to claim 1, wherein in step S2, the mass ratio of the isolated soybean protein to the methacryl oxyethyl choline chloride monomer is 1 (0.5-1.5).
  5. 5. The method according to claim 1or 4, wherein in the step S2, the redox initiator is composed of potassium persulfate and sodium bisulphite, the total addition amount of the redox initiator is 1% -3% of the amount of the isolated soy protein, and the graft copolymerization reaction is carried out at 45-55 ℃ for 4-5 hours.
  6. 6. The method according to claim 1, wherein in step S3, the buffer solution is sodium bicarbonate solution.
  7. 7. The method according to claim 1, wherein in step S4, the freeze-drying is performed at a temperature of-50 ℃ and below, and the drying time is not less than 24 hours.
  8. 8. A choline ionic liquid modified soy protein flocculant characterized in that it is produced by the production method of any one of claims 1 to 7, and has a cationic charge center, biodegradability and antibacterial activity.
  9. 9. Use of the choline ionic liquid modified soy protein flocculant of claim 8 in water treatment, wherein the water treatment comprises microbiological removal in domestic sewage decolorization, algae-containing wastewater treatment, landscape water remediation, or potable water pretreatment.
  10. 10. The use according to claim 9, wherein the flocculant is added in an amount of 5 mg/L to 25/mg/L for domestic sewage decolorization, algae-laden wastewater treatment, landscape water remediation or drinking water pretreatment.

Description

Choline ionic liquid modified soybean protein flocculant and preparation method and application thereof Technical Field The invention belongs to the technical field of water treatment, and particularly relates to a choline ionic liquid modified soybean protein flocculant, a preparation method and application thereof. Background With global importance on green chemistry and ecological safety, "detoxication" of water treatment agents has become an important topic in the environmental field. Although the existing flocculation technology can effectively remove suspended matters in water, the common Polyacrylamide (PAM) flocculant is extremely difficult to degrade in nature, and monomers generated by degradation of the flocculant have obvious biotoxicity. In addition, although the charge neutralization capacity of the traditional quaternary ammonium salt modified biomass flocculant is improved, the used modifying reagent often has a certain environmental risk, and the treated water body is difficult to meet the high-standard ecological recycling requirement. Soy Protein Isolate (SPI), which is a natural protein, consists of 7S and 11S globulin subunits with complex conformations, has excellent biodegradability. However, natural soy proteins have a low charge density and are inefficient to flocculate in high salinity or complex microbial environments. The ionic liquid is used as a novel functional material which can be designed, and the unique charge distribution and physicochemical properties of the ionic liquid provide a new idea for modifying biological macromolecules. Particularly, the choline ionic liquid, as a functional monomer derived from natural nutrients, has extremely high positive charge density, excellent biocompatibility and antibacterial activity. The existing protein modification technology depends on traditional chemical reagents, and perfect balance of efficient flocculation and ecological safety is difficult to realize. Therefore, the preparation process for modifying the soybean protein by using the choline ionic liquid is explored, so that the charge neutralization and bridging capacity of the soybean protein flocculant can be remarkably improved, and the soybean protein flocculant can be endowed with a unique antibacterial function and extremely low ecological toxicity. The method has profound technical value for developing the next generation 'zero footprint' environment-friendly water treatment medicament and guaranteeing the recycling of high-quality water resources. Disclosure of Invention The invention aims to provide an efficient, green and multifunctional choline ionic liquid modified soybean protein flocculant, a preparation method and application thereof, aiming at the imbalance problem of flocculation efficiency and toxic residues of the existing turbidity reducing flocculant. The invention provides a preparation method of a choline ionic liquid modified soybean protein flocculant, which comprises the following steps: S1, regulating the pH value of a soy protein isolate aqueous solution to 8.5-10.5, stirring at 40-50 ℃, introducing nitrogen to drive oxygen for at least 20 minutes, and inducing protein subunits to be unfolded; s2, under the protection of nitrogen, adding a redox initiator, and then adding a solution of a methacryloyloxyethyl choline chloride monomer to perform graft copolymerization reaction; s3, adding a buffer solution to adjust the pH to 6.5-7.5, and standing and aging for 2-4 hours at room temperature after terminating the reaction; S4, precipitating and washing the product with absolute ethyl alcohol, and freeze-drying to obtain the flocculant. The invention also provides a choline ionic liquid modified soybean protein flocculant which comprises a soybean protein skeleton and a methacryloxyethyl choline group grafted on the soybean protein skeleton, and has a cationic charge center, biodegradability and antibacterial activity. The flocculant can be used for decoloring domestic sewage, treating algae-containing wastewater, repairing landscape water or pretreating drinking water, and the adding amount of the flocculant is 5 mg/L-25 mg/L. The invention has the beneficial effects that: (1) Realizing ecological safety and environmental protection. The choline ionic liquid selected by the invention is derived from natural nutrient groups, and the modified flocculant can be completely degraded, and degradation products are harmless to the environment. The ecological toxicity of the water treatment agent is far lower than that of the traditional polyacrylamide and quaternary ammonium salt flocculant, and the water treatment agent is suitable for scenes with nearly harsh safety requirements, such as pretreatment of drinking water, restoration of landscape water and the like. (2) The flocculant is endowed with unique antibacterial function. The choline ionic liquid has a certain osmotic damage effect on bacterial and algae cell membranes. The method can effectively avoi