PVP in Water Treatment

PVP is a water-soluble polymer with excellent hydrophilicity. The addition of PVP can greatly improve the hydrophilicity of polyvinylidene fluoride (PVDF), polyethersulfone (PES), polysulfone (PS), etc. When PVP is used as a pore former, it will be enriched on the surface of the membrane. When the surface of the membrane contacts water, PVP will dissolve in water to form a channel for non-solvent to enter the inside of the membrane, and these points constitute the growth points of the finger-like pores, which grow toward the membrane matrix in the subsequent process to form finger-like pores. Finally, the polymer concentrated phase forms a membrane, and the polymer dilute phase is eluted. The addition ratio of PVP is generally 2-8 wt% (this range is not fixed and should be determined according to the specific membrane making conditions). The increase in the amount of addition will increase the membrane porosity, but reduce the strength and hydrophobicity of the membrane, which will affect the performance of the membrane.