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CN-116651226-B - Calcium alginate composite membrane with anti-biofilm performance and preparation method and application thereof

CN116651226BCN 116651226 BCN116651226 BCN 116651226BCN-116651226-B

Abstract

The invention relates to a calcium alginate composite membrane with an anti-biofilm performance, a preparation method and application thereof, wherein the composite membrane is obtained by coating a micro-nano coating on the surface of a micro-filtration membrane and has super-hydrophilic/underwater super-oleophobic performance, the micro-nano coating is a composite material of chitosan, silver nano particles and calcium alginate, the micro-nano coating has a fibrous three-dimensional porous structure, and the silver nano particles are densely distributed on the surface and the inside of the coating. The calcium alginate composite membrane with the anti-biological membrane performance provided by the invention has the advantages that the micro-pore structure is provided by the micro-filtration membrane, and the silver nano particles wrapped by chitosan provide the nano structure, so that the prepared composite membrane has super-hydrophilic/underwater super-oleophobic performance, good antibacterial performance and good anti-biological membrane capability, can effectively separate an oil-water mixture and even oil-in-water emulsion with stable surfactant, has high separation flux, and can be suitable for oil-water separation in complex water environment.

Inventors

  • YANG HAO
  • Cheng Huajing
  • TANG QIJIN

Assignees

  • 武汉工程大学

Dates

Publication Date
20260512
Application Date
20230531

Claims (10)

  1. 1. The calcium alginate composite membrane with the anti-biofilm performance is characterized in that the calcium alginate composite membrane is obtained by coating a micro-nano coating on the surface of a micro-filtration membrane and has super-hydrophilic/underwater super-oleophobic performance, the micro-nano coating is a composite material of chitosan, silver nano particles and calcium alginate, the micro-nano coating has a fibrous three-dimensional porous structure, and the silver nano particles are densely distributed on the surface and the inside of the coating.
  2. 2. The calcium alginate composite membrane with anti-biofilm performance according to claim 1, wherein the aperture of the microfiltration membrane is 2-5 μm and the thickness is 50-100 μm.
  3. 3. The calcium alginate composite membrane with the anti-biofilm performance according to claim 1, wherein the microfiltration membrane is one of a nylon membrane, a polyvinylidene fluoride membrane, a polypropylene membrane and a glass fiber membrane.
  4. 4. The calcium alginate composite film having an anti-biofilm property according to claim 1, wherein the particle size of the silver nanoparticle is 10-300nm.
  5. 5. The calcium alginate composite membrane with the anti-biofilm performance according to claim 1, wherein the contact angle of the calcium alginate composite membrane with the anti-biofilm performance to normal hexane, toluene and petroleum ether under water is 162.7-169.1 degrees, the calcium alginate composite membrane has super-hydrophilicity in air, the water drop just contacts the surface of the composite membrane for 0ms, and the calcium alginate composite membrane can be completely soaked by only 2.0-3.0s of water drop.
  6. 6. A method for preparing the calcium alginate composite membrane with the anti-biofilm performance according to any one of claims 1 to 5, which is characterized by comprising the following specific steps: 1) Dissolving chitosan in acetic acid aqueous solution to obtain chitosan acetic acid aqueous solution, adding silver nitrate solution into the obtained chitosan acetic acid aqueous solution, fully and uniformly stirring under heating, then adding sodium borohydride solution dropwise while stirring, continuing stirring reaction for 90-180min, and stopping heating to obtain chitosan-nano silver mixed solution; 2) Adding sodium alginate powder into the chitosan-nano silver mixed solution obtained in the step 1) while stirring, stirring uniformly at normal temperature, and filtering to obtain a sodium alginate/chitosan-nano silver mixed solution; 3) And (3) soaking the micro-filtration membrane with the clean surface in the sodium alginate/chitosan-nano silver mixed solution obtained in the step (2) for 5-30min, taking out, soaking in a calcium chloride solution, taking out the membrane after 5-30min, and drying at normal temperature to obtain the calcium alginate composite membrane with the anti-biofilm performance.
  7. 7. The method for producing a calcium alginate composite film having an anti-biofilm property according to claim 6, wherein in step 1), the chitosan has a degree of deacetylation of 70 to 100%, a viscosity of 200 to 400 mPa-s, the aqueous acetic acid solution has a concentration of 0.1 to 1.0mol/L, and the chitosan in the aqueous chitosan acetic acid solution has a concentration of 2.0 to 3.0g/L.
  8. 8. The preparation method of the calcium alginate composite film with the anti-biofilm performance according to claim 6, wherein the mass ratio of chitosan to silver nitrate in a silver nitrate solution in the step 1) is 5-6:1, the concentration of the silver nitrate solution is 0.1-1.0mol/L, the concentration of the sodium borohydride solution is 0.1-1.0mol/L, the molar ratio of sodium borohydride in the sodium borohydride solution to silver nitrate in the silver nitrate solution is 1.2-2:1, the heating temperature is 40-60 ℃, and the mass volume ratio of sodium alginate powder to chitosan-nano silver mixed solution is 1-5g/L.
  9. 9. The method for preparing a calcium alginate composite membrane having an anti-biofilm property according to claim 6, wherein the concentration of the calcium chloride solution in the step 2) is 4-10wt%.
  10. 10. Use of the calcium alginate composite membrane with anti-biofilm performance according to any one of claims 1 to 5 in the field of oil-water emulsion separation.

Description

Calcium alginate composite membrane with anti-biofilm performance and preparation method and application thereof Technical Field The invention belongs to a semipermeable membrane for a separation process or equipment, which is characterized by materials, and particularly relates to a calcium alginate composite membrane with an anti-biofilm performance, a preparation method thereof and application thereof in oil-water emulsion separation. Background The oily substances and the organic solvent enter the water body to form oily wastewater, and the wastewater seriously affects the environment and ecology, so that the potential safety hazard is not small for the health of people. Therefore, how to treat these oily wastewater efficiently, economically and safely becomes an important issue for ecological protection. Oily wastewater is generally divided into two categories, stratified oil/water mixtures and oil-water emulsions. The layered oil/water mixture containing relatively large dispersed droplets (> 20 μm) can naturally separate oil and water over time due to thermodynamic instability, with the dense phase gradually settling, and the lighter phase floating to the top, making oil-water separation easier. However, oil-water emulsions (< 20 μm) are thermodynamically stable colloidal dispersions consisting of micro/nano-sized droplets of a dispersed phase in a continuous phase, coupled with the widespread use of surfactants, making them generally very stable and difficult to separate naturally over time. The traditional treatment methods of the oily wastewater comprise a centrifugal method, an incineration method, a chemical dispersion method, a biological degradation method and the like, and the methods have the problems of complex operation, high cost and the like, and have poor treatment effect on the oil-water emulsion. The membrane filtration technology is considered as the most effective method for treating the oil-water mixture due to low cost and simple operation process, and is widely applied in industry, and particularly, the special wettability membrane separation technology developed in recent years, such as a super-hydrophilic/underwater super-oleophobic separation membrane, has the advantages of simple operation method, good separation effect, high treatment rate and the like, is considered as a more attractive oil-water separation method, and is still difficult to separate the oil-water emulsion. The hydrogel is used as a hydrophilic polymer with swelling performance, has the characteristics of no toxicity, good biocompatibility and the like, is rich in hydrophilic functional groups (hydroxyl, carboxyl, amino and thio), has very strong hydrophilic performance, is environment-friendly, and can be widely applied in practice. Among various hydrogels, alginate is a natural material, and has been receiving a great deal of attention due to its strong hydration ability. However, the oily wastewater has complex components, not only has emulsion drops, dyes, heavy metal ions and the like, but also contains various bacteria, and the bacteria are easy to pollute and adhere to the surface of the separation material to cause biological pollution. More specifically, the biofilm formed by bacteria can partially and completely cover the surface of the separation membrane, and the phenomenon can cause the blockage of the pores of the separation membrane, thereby greatly attenuating the separation efficiency and flux, so that the development of the oil-water emulsion separation membrane with the anti-biofilm performance has important significance. Often et al (CN 113101816A) the silver nitrate solution and cellulose nanocrystalline are used for preparing the composite membrane with the anti-biofilm performance and the emulsion separation performance, but the preparation process parameters are high (high temperature and high pressure), the separation flux is low, and only a simple paper sheet diffusion experiment is carried out. The antibacterial PTFE oil-water separation film is obtained by using a copolymer modified polytetrafluoroethylene film by Monte et al (CN 113069938A), but the complicated preparation process is a great disadvantage. Wu et al (CN 113750815A) disclose a switchable emulsion type oil-water separation nano-antibacterial film, however, the material adopts fluorine-containing materials, which is not environment-friendly. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a calcium alginate composite membrane with anti-biofilm performance, a preparation method and application thereof, the calcium alginate composite membrane has super-hydrophilic/underwater super-oleophobic performance, has good antibacterial performance, can inhibit the formation of a biological membrane, can realize the effective separation of stable emulsion containing surfactant, and has high separation flux. In order to solve the technical problems, the technical scheme provided by t