CN-122006673-A - Preparation method and application of biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment

CN122006673ACN 122006673 ACN122006673 ACN 122006673ACN-122006673-A

Abstract

A preparation method and application of a biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment relate to a preparation method and application of a biomass-based molecularly imprinted polymer. The invention aims to solve the defects that the traditional powdery MIPs are difficult to elute and difficult to recycle, and the problems of low adsorption rate and low adsorption capacity of the traditional MIPs, and the MIPs are not tightly combined with biomass materials, so that the low-cost environment-friendly and efficient adsorption cannot be achieved. The preparation method comprises the steps of preparing nanofibers, preparing fiber/PVA composite materials, and preparing fiber-based molecularly imprinted materials. The application of the catalyst is as an adsorbent for adsorbing methylene blue pollutants in water.

Inventors

YIN RAN
LIN SHAOHAN
ZHANG YUEYING
YAN JIARUI
HUANG FEIYANG
ZHANG REN

Assignees

东北林业大学

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

1. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment is characterized by comprising the following steps of: 1. preparation of nanofibers: ① Delignification treatment is carried out on wood shavings, then the wood shavings are washed until the pH value is neutral, and finally freeze-drying is carried out, so that delignified shavings are obtained; ② Dispersing the delignified wood shavings in a sodium hydroxide solution and stirring to obtain a fiber solution; 2. Preparation of fiber/PVA composite material: ① Mixing the fiber solution with the PVA solution, adding glycoside to obtain a mixed system, foaming the mixed system by adopting a stirring method to obtain a foamed system, naturally drying and molding the foamed system, washing the molded system until the pH value is neutral, and finally freeze-drying to obtain the foam material; ② Immersing the foam material into a modified solution for water bath reaction, then washing, and finally drying in vacuum to obtain a fiber/PVA composite material; 3. Preparing a fiber-based molecularly imprinted material: Under the atmosphere of N 2 , methylene blue template molecules, methacrylic acid functional monomers and fiber/PVA composite materials are added into methanol for preassembling, then a cross-linking agent and an initiator are sequentially added for constant-temperature polymerization, and finally elution of the template molecules and washing are sequentially carried out until the pH value is neutral, so that the biomass-based molecularly imprinted polymer for adsorbing the methylene blue pollutants in the water environment is obtained.
2. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in an aqueous environment, which is characterized by comprising the following steps of carrying out delignification treatment on wood shavings in the step one ①, wherein the wood shavings are soaked in sodium chlorite solution with the concentration of 3-5 wt%, then the pH value is adjusted to 4-5 by using glacial acetic acid, lignin in the wood shavings is completely removed, and the freeze-drying in the step one ① is carried out under the condition that the temperature is minus 24 ℃ to minus 48 ℃ for 36-48 hours.
3. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in an aqueous environment, which is disclosed in claim 1, is characterized in that the concentration of sodium hydroxide in a sodium hydroxide solution in the step one ② is 10-13 wt%, the concentration of fibers in a fiber solution in the step one ② is 2-3 wt%, and the stirring in the step one ② is specifically carried out under the condition that the stirring speed is 500-700 rpm for 12-24 hours.
4. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment, which is characterized in that PVA solution in the step two ① is added into deionized water, the PVA solution is heated for 3.5-4 hours under the conditions of sealing and temperature of 85-95 ℃, the concentration of PVA in the PVA solution is 5-10 wt%, glucoside in the step two ① is alkyl glucoside, 5-6 drops of glucoside are added dropwise to each 66mL of fiber solution in the step two ①, and the mass ratio of fiber to PVA in the mixed system in the step two ① is 1 (1.2-1.7).
5. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment is characterized by adopting a stirring method to foam a mixed system in the second ① step, specifically comprising the steps of stirring and foaming for 10-30 min under the condition of 2000-2200 rpm, and adopting natural drying and molding the foamed system in the second ① step, specifically comprising the steps of paving the foamed system in a polytetrafluoroethylene mold uniformly, then standing and molding at room temperature for 24-36 h to obtain a preliminarily stable foam structure, and freeze-drying for 36-48 h in the second ① step at the temperature of minus 24-48 ℃.
6. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in an aqueous environment according to claim 1, wherein the modified solution in the step two ② is obtained by mixing a silane coupling agent, acetic acid and absolute ethyl alcohol, the mass ratio of the silane coupling agent to the acetic acid is 1 (0.6-0.7), and the mass ratio of the silane coupling agent to the absolute ethyl alcohol is 1 (30-35).
7. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in an aqueous environment, which is disclosed in claim 1, is characterized in that the water bath reaction in the step two ② is carried out for 3.5-4 hours under the condition that the temperature is 55-60 ℃, the washing in the step two ② is carried out by washing unreacted substances by absolute ethyl alcohol firstly and then washing the unreacted substances to be neutral in pH by deionized water, and the vacuum drying in the step two ② is carried out under the condition that the temperature is 50-60 ℃.
8. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment is characterized in that the cross-linking agent in the step three is ethylene glycol dimethacrylate, the initiator in the step three is azodiisobutyronitrile, the molar ratio of the methylene blue template molecule to the methacrylic acid functional monomer in the step three is 1 (12-13), the mass ratio of the methylene blue template molecule to the fiber/PVA composite material in the step three is 1mmol (1-1.5) g, the volume ratio of the methylene blue template molecule to methanol in the step three is 1mmol (70-80) mL, the molar ratio of the methylene blue template molecule to the cross-linking agent in the step three is 1 (7-8), and the molar ratio of the methylene blue template molecule to the initiator in the step three is 1 (2-3).
9. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment, which is characterized by comprising the steps of adding methylene blue template molecules, methacrylic acid functional monomers and fiber/PVA composite materials into methanol in N 2 atmosphere, pre-assembling for 10-12 h in N 2 atmosphere at 40-45 ℃, sequentially adding a cross-linking agent and an initiator, polymerizing for 12-24 h at constant temperature in N 2 atmosphere at 60-65 ℃, eluting the template molecules by adopting a mixed solvent of methanol and acetic acid in a volume ratio (9-10): 1, and finally washing with deionized water to be neutral in pH.
10. Use of a biomass-based molecularly imprinted polymer for adsorbing methylene blue contaminants in an aqueous environment prepared according to claim 1, characterized in that it is used as an adsorbent for adsorbing methylene blue contaminants in water.

Description

Preparation method and application of biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment Technical Field The invention relates to a preparation method and application of a biomass-based molecularly imprinted polymer. Background Methylene blue is an important cationic dye and has been widely used in the fields of dyeing, chemical analysis, medical treatment and the like. However, the water ecological system is seriously threatened by strong colorability, ecological toxicity and difficult degradation, and the risk of mutation is hidden by biological enrichment, so that a green and efficient wastewater treatment technology is urgently needed. Traditional adsorption materials (such as activated carbon) are limited by high cost, low selectivity and non-regenerability, while biomass wastes (such as wood sawdust) are cheap and environment-friendly, but the natural adsorption performance is difficult to meet the complex wastewater purification requirement. To improve selectivity, molecular imprinting techniques are introduced into this field. The Molecular Imprinting Polymer (MIPs) can realize specific 'lock key' recognition of a target object by constructing a three-dimensional cavity which is highly complementary with a template molecule (such as methylene blue) in shape, size and functional group in advance, but the MIPs can specifically recognize pollutants, but the traditional powdery MIPs have the defects of difficult elution and difficult recovery, so that the actual application is restricted, and meanwhile, the existing MIPs also have the problems of low adsorption rate and low adsorption capacity, are not tightly combined with biomass materials, and cannot achieve the effects of low-cost environmental protection and high-efficiency adsorption. Disclosure of Invention The invention aims to solve the defects that the traditional powdery MIPs are difficult to elute and difficult to recycle, and meanwhile, the traditional MIPs also have the problems of low adsorption rate and low adsorption capacity, and the MIPs are not tightly combined with biomass materials and cannot give consideration to low-cost environment protection and efficient adsorption, so that the preparation method and the application of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment are provided. The preparation method of the biomass-based molecularly imprinted polymer for adsorbing methylene blue pollutants in water environment comprises the following steps: 1. preparation of nanofibers: ① Delignification treatment is carried out on wood shavings, then the wood shavings are washed until the pH value is neutral, and finally freeze-drying is carried out, so that delignified shavings are obtained; ② Dispersing the delignified wood shavings in a sodium hydroxide solution and stirring to obtain a fiber solution; 2. Preparation of fiber/PVA composite material: ① Mixing the fiber solution with the PVA solution, adding glycoside to obtain a mixed system, foaming the mixed system by adopting a stirring method to obtain a foamed system, naturally drying and molding the foamed system, washing the molded system until the pH value is neutral, and finally freeze-drying to obtain the foam material; ② Immersing the foam material into a modified solution for water bath reaction, then washing, and finally drying in vacuum to obtain a fiber/PVA composite material; 3. Preparing a fiber-based molecularly imprinted material: Under the atmosphere of N 2, methylene blue template molecules, methacrylic acid functional monomers and fiber/PVA composite materials are added into methanol for preassembling, then a cross-linking agent and an initiator are sequentially added for constant-temperature polymerization, and finally elution of the template molecules and washing are sequentially carried out until the pH value is neutral, so that the biomass-based molecularly imprinted polymer for adsorbing the methylene blue pollutants in the water environment is obtained. The application of the catalyst is as an adsorbent for adsorbing methylene blue pollutants in water. The beneficial effects of the invention are as follows: The invention has the core advantages that the contradiction that the traditional adsorption material is difficult to be compatible between high selectivity and easy recovery is solved through the synergistic design of biomass nano-fibrosis, surface molecular imprinting and natural drying molding. Aiming at the defects of difficult separation and easy secondary pollution of powdery Molecularly Imprinted Polymers (MIPs), imprinting sites are constructed on the surfaces of wood saw dust derived nanofibers, and PVA is added to further prepare the self-supporting composite material. Can be directly and completely taken out of the water body, realizes instantaneous and thorough solid-liquid separation, has extremely simple and convenient operation, a