Method for preparing super-hydrophobic mixed matrix membrane by inorganic particle induced phase separation

Abstract

The invention discloses a method for preparing a super-hydrophobic mixed matrix membrane by inorganic particle induced phase separation. According to the method, inorganic particles having proper grain size and the surface carrying hydroxy and other hydrophilic radicals in a casting membrane solution system consisting of polymer / solvent / additive / inorganic particles are induced in the phase separating process under the interface interaction of particle surface functional groups and polymer chains and the like to form a micron-sized microsphere structure which takes the particles as a core, wherein polymer coats the surface. The polymer chain on the microsphere surface forms a nano-microspike structure in the phase separating curing process, so that a super-hydrophobic micro-structure with a lotus leaf-like surface is formed on the membrane surface, the microsphere extends to the membrane body from the membrane surface, the duct of the membrane body has excellent hydrophobicity due to the similar structure, and the hydrophobic stability and durability of the separation membrane can be promoted.

Description

technical field [0001] The invention belongs to the field of membrane separation, and relates to a method for preparing a hybrid superhydrophobic membrane, in particular to a method for preparing a superhydrophobic mixed matrix membrane by inducing phase separation with inorganic particles. Background technique [0002] In recent years, membrane separation technology has been highly valued by many countries in the world. Membrane distillation (MD for short) is a membrane separation process that uses a hydrophobic microporous membrane and uses the vapor pressure difference on both sides of the membrane as the driving force for mass transfer. MD has gradually become a new type of membrane separation technology widely used due to its advantages such as high interception efficiency, direct access to ultrapure water, mild operating conditions, and ability to handle high-concentration raw material solutions. The hydrophobicity of the membrane for membrane distillation is an impor...

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Problems solved by technology

(2) The in-situ polymerization method is to mix the nanoparticles and the organic monomer evenly, and under appropriate conditions, such as high-energy radiation, plasma treatment, etc., induce the hydroxyl groups on the surface of the inorganic particles to generate free radicals, thereby triggering the formation of monomers on the surface of the film. Aggregation, which is cumbersome and difficult to control

(3) The sol-gel method is to dissolve the inorganic precursor in water or an organic solvent to form a uniform solution, and generate a sol with a particle size of nanometer through hydrolysis and condensation reaction under acidic or alkaline conditions, and then dry The method of turning into a gel, the whole reaction process of this method is carried out in the solution, it is easy to produce waste liquid, which is not conducive to environmental protection

By controlling the different coagulation baths, the prepared PVDF symmetric membrane has a microsphere structure, which has been studied in membrane distillation. The results show that this microsphere structure is conducive to improving the hydrophobicity of the membrane and improving the efficiency of membrane distillation. However, there is no research report on it at present. Preparation of hybrid superhydrophobic membrane by blending inorganic particles with hydroxyl functional groups and PVDF

[0005] Common methods for preparing superhydrophobic membranes: (1) Coating a layer of low surface energy substances on the surface of the membrane can not only increase the roughness of the membrane surface but also reduce the surface energy of the membrane, but the coating and the membrane matrix have poor adhesion , it is easy to fall off during long-term operation, and the coating will increase the water vapor penetration resistance and reduce the flux

(2) Grafting substances with low surface energy on the surface of the membrane, by grafting substances with low surface energy, reducing the surface energy of the membrane, thereby improving the hydrophobicity of the membrane, but this method is more complicated to operate

Membrane performance is also not ideal

[0012] At present, there is no research report on the use of hydroxyl groups carried by inorganic particles to affect the phase separation behavior of PVDF membranes and then affect its microstructure to prepare hybrid superhydrophobic membranes.

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