The invention relates to a
polyvinylidene fluoride membrane. The membrane
casting liquid comprises the following components in percentage by weight: 10-25% of
polyvinylidene fluoride resin, 1-4% of diatomite, 1-5% of
amphiphilic copolymer, 4-12% of organic pore-forming agent, 0.2-3% of inorganic pore-forming agent, 0.1-3% of surfactant and the balance of
solvent. According to the
polyvinylidene fluoride membrane, the diatomite and the
amphiphilic copolymer are added; by virtue of the diatomite, the
mechanical strength and pure water flux of the membrane are improved; the
amphiphilic copolymer and polyvinylidene
fluoride have good compatibility; the combination force is strong; the
copolymer is unlikely to run off and the continuous
hydrophily of the membrane is guaranteed. The invention further relates to a preparation method of the polyvinylidene
fluoride membrane. The preparation method comprises the following steps: (1) uniformly stirring the membrane
casting liquid, standing and defoaming; (2) enabling the membrane
casting liquid to vertically flow in the air by virtue of a
spinning spinneret, so that the membrane casting liquid enters the coagulating bath and is cured and formed; (3) soaking the spun and formed polyvinylidene
fluoride membrane in pure water and a
glycerol water solution in sequence and
drying so as to obtain the polyvinylidene fluoride membrane.