CN-116651238-B - Method for preparing SPEEK/MS porous composite membrane by adopting non-solvent induced phase separation and application thereof

Abstract

The invention discloses a method for preparing a SPEEK/MS porous composite membrane by adopting non-solvent induced phase separation and application thereof, belonging to the field of cation separation membranes. According to the invention, mesoporous silica is doped into the sulfonated polyether ether ketone (SPEEK), so that the separation performance of the prepared cation porous composite membrane is greatly improved. The method is simple and easy to operate, is less interfered by external factors, and can obtain the SPEEK/MS composite membrane with higher separation performance under the condition of small addition amount of inorganic particles, wherein the hydroxyl dialysis coefficient (U OH ) of the composite membrane is 0.0089-0.0139m/h, and the separation coefficient (S) is 21.4-35.6.

Inventors

• MIAO JIBIN
• ZHENG ZHENGZHI
• GE QIANQIAN
• JIANG SHUDONG
• LI XUE
• QIAN JIASHENG
• XIA RU
• CHEN PENG
• YANG BIN
• CAO MING
• WU BIN
• SU LIFEN

Assignees

• 安徽大学

Dates

Publication Date

20260505

Application Date

20230530

Claims (4)

1. 1. A method for preparing a SPEEK/MS porous composite membrane by non-solvent induced phase separation, comprising the steps of: Adding the dried polyether-ether-ketone particles into concentrated sulfuric acid, mechanically stirring for 12 hours at room temperature in a nitrogen atmosphere to obtain dark red homogeneous solution, then heating, continuing to react, slowly pouring the solution into an ice-water mixture after the solution is cooled to room temperature, stirring with a glass rod to obtain white fibrous precipitate, washing the precipitate with deionized water until the pH value of a washing solution is about 7, and vacuum-drying the obtained precipitate to obtain yellow fibrous solid, namely SPEEK; Step 2, dissolving P123 in diluted HCl solution, dripping silicon source TEOS into the mixed solution, stirring the mixture for a certain time, and then heating and stirring; Step 3, grinding the mesoporous silica microspheres MS obtained in the step 2, adding the ground mesoporous silica microspheres MS into 16mLDMF for ultrasonic dispersion for 1h, then adding 4g SPEEK, magnetically stirring at 70 ℃ for 12h until the mixture is completely dissolved to form yellowish viscous transparent homogeneous solution, stopping stirring, standing for 2h to remove bubbles in the solution, pouring the feed liquid on a clean glass plate, driving the liquid by a doctor blade of a doctor blade to cast the feed liquid into a film, immediately soaking the cast film in ethanol solution for 24h, taking out the film, and naturally drying the film to obtain the SPEEK/MS composite porous cation exchange membrane; In step 1, the prepared SPEEK has a sulfonation degree of 48% -65%; In the step 2, the adding proportion of P123 is 1g/30mL of HCl solution; in the step 3, the added mass of the MS is 2-8% of the mass of the SPEEK; the SPEEK/MS porous composite membrane comprises a dense epidermal layer on the surface of the membrane and a porous supporting layer below the epidermal layer, wherein the thickness of the dense epidermal layer is 0.01-0.1 mu m.
2. 2. The method according to claim 1, characterized in that: in the step 1, the proportion of the polyether-ether-ketone particles to the concentrated H 2 SO 4 is 1g/25mL, and the temperature is raised to 60 ℃ for sulfonation after a dark red homogeneous solution is obtained, and the sulfonation reaction time is 3H.
3. 3. The method according to claim 1, characterized in that: in the step 2, the calcination temperature is 550 ℃, the calcination time is 4 hours, and the temperature rising speed is 10 ℃ per minute.
4. 4. The use of a SPEEK/MS porous composite membrane prepared by a method according to any one of claims 1-3, characterized in that the SPEEK/MS porous composite membrane is used as a cation exchange membrane in a basic diffusion dialysis process.

Description

Method for preparing SPEEK/MS porous composite membrane by adopting non-solvent induced phase separation and application thereof Technical Field The invention relates to a preparation method of a porous composite membrane with an asymmetric membrane structure, in particular to a method for preparing a SPEEK/MS porous composite membrane by adopting non-solvent induced phase separation and application thereof. Background With the increasing demands of the modern industry for environmental protection and wastewater discharge, how to treat large amounts of continuously produced industrial wastewater has become a focus of attention. The traditional treatment method comprises neutralization, concentration, incineration and the like, so that the energy consumption is high and the environment is not protected. The membrane separation provides an environment-friendly, low-energy-consumption and simple-operation treatment mode for the treatment of industrial wastewater. At present, many researchers study dense membranes, but reports on application of porous ion exchange membranes to diffusion dialysis are few. In comparison, the porous structure inside the porous ion exchange membrane gives more free space volume to ions, thereby reducing the ion movement resistance and being more beneficial to the ion transmission. The pure polymer membrane has the problems of poor separation performance and the like caused by low sulfonation degree, and the performance of the pure polymer membrane needs to be improved. According to the existing research, the mesoporous silica has the advantages of unique structural characteristics, low production cost, easiness in synthesis and surface functionalization, easiness in aperture and morphology regulation, good stability and the like, is a hot spot problem in the research of the material and chemical industry field, and is often introduced into a polymer membrane as a carrier constructed by an ion transmission channel to improve the performance of the membrane due to the advantages of a regular channel structure, higher specific surface area, porosity and the like. The non-solvent induced phase separation (NIPS) film forming method is an efficient film forming method invented in the 60 th century. NIPS is an abbreviation for non-solvent induced phase separation (Nonsolvent Induce Phase Separation), also known as wet process. The process flow is to dissolve the polymer in the solvent to form homogeneous solution, then to slowly add the reagent (called extractant) with stronger mutual solubility with the solvent to extract the solvent to form two-phase structure with the polymer as continuous phase and the solvent as disperse phase, and then to remove the solvent to obtain the polymer with a certain pore structure. The basic principle of NIPS film making is that through certain physical method, the solvent and non-solvent in homogeneous polymer solution with certain composition are double diffused to change the thermodynamic unstable state of the polymer solution, i.e. solid-liquid or liquid-liquid phase separation, and finally converted into three-dimensional macromolecular reticular gel structure, which is to form porous structure after polymer lean phase elution. The asymmetric membrane formed by the NIPS method comprises a dense epidermal layer on the surface of the membrane and a support layer with holes under the epidermal layer. By selecting the proper casting solution formula and process conditions, various polymer films can be prepared. The pore structure of the membrane is approximately four of sphere, sponge, macropore and open network. Zhang Wenjuan [1] and the like adopt gamma-butyrolactone (gamma-BL) and TEP as mixed solvents, and PVDF film is prepared by using NIPS method, and the influence of different solvent proportions on the structure and performance of PVDF film is studied. The result shows that when the content of gamma-BL in the mixed solvent is higher (more than 80%), the cortex of the obtained film is thicker and the spherulites of the cross section are densely accumulated, and as the content of TEP in the solvent is increased, the cortex of the prepared film is gradually thinned to disappear, and the spherulites structure of the cross section of the film is also more loose. Xu Zhenliang [2] respectively adopts DMAc and N-methylpyrrolidone (NMP) as solvents to prepare a PVDF hollow fiber ultrafiltration membrane by NIPS method, and researches the influence of different solvent compositions on the performance of the hollow fiber membrane, and the result shows that the pure water flux of the membrane prepared by using NMP as solvent is larger than that of the membrane prepared by using DMAc as solvent, and the retention rate is smaller than that of the membrane prepared by using DMAC as solvent. The NIPS process has numerous advantages over conventional porous membrane preparation processes. The asymmetric membrane structure prepared by the method endows the membran