Hydrophilic polyvinylidene fluoride two-layer membrane and preparation method thereof

Abstract

The invention relates to a hydrophilic polyvinylidene fluoride two-layer membrane and a preparation method thereof. A supporting layer of the two-layer membrane is made of polyvinylidene fluoride, and a membrane separation layer of the surface is made of polyvinylidene fluoride-g-methoxy polyethylene glycol methacrylate, wherein the thickness of the membrane supporting layer is 50-250 micrometers, and the thickness of the membrane separation layer is 5-50 micrometer. Nano powder obtained after being wrapped by polyvinylidene fluoride and an organic additive or inorganic additive or dopamine is dissolved in an organic solvent to be prepared into a supporting layer membrane casting solution, polyvinylidene fluoride-g-methoxy polyethylene glycol methacrylate is dissolved in an organic solvent to be prepared into a membrane separation membrane casting solution, and a two-layer membrane blank is prefabricated through a membrane casting machine or a spinning machine; after the blank is subjected to consolidation forming and washed with deionized water, the polyvinylidene fluoride-g-methoxy polyethylene glycol methacrylate and polyvinylidene fluoride two-layer membrane is obtained. The prepared two-layer membrane is high in hydrophilia, large in pure water flux, high in retention rate and good in anti-fouling performance.

Description

technical field [0001] The invention belongs to the field of membrane material manufacturing, and relates to a polyvinylidene fluoride double-layer membrane with high hydrophilicity, high rejection rate and good pollution resistance and a preparation method thereof. Background technique [0002] Membrane separation technology is a new separation technology that emerged rapidly after the 1960s, and has the functions of separation, purification and concentration. Polyvinylidene fluoride (PVDF) has excellent chemical corrosion resistance, oxidation resistance and heat resistance. It is a typical membrane material and has been widely used in the field of membrane separation. However, the surface energy of PVDF is low, the wettability is poor, and the membrane surface is easily polluted, which finally reduces the two main indicators of membrane flux and rejection. One of the methods to effectively reduce membrane fouling is to modify it hydrophilically. [0003] Aiming at the m...

AI Technical Summary

Problems solved by technology

However, the addition of blended particles is limited, and the performance of the membrane can only be improved to a limited extent.

Moreover, inorganic nanoparticles or organic small molecule polymers are easy to lose during the use of the membrane, which seriously affects the separation performance of the membrane.