(270e) Green Preparation of PVDF Microfiltration Membranes Via Thermally Indueced Phase Separation Method Using Diphenyl Carbonate and Diphenyl Ketone As Diluents

The green production process of polyvinylidene fluoride (PVDF) hollow fiber membranes was successfully developed via thermally induced phase separation (TIPS) method using the diluents such as diphenyl carbonate (DPC) and diphenyl ketone (DPK). By changing the ratio of DPC to DPK from 9:1 to 3:7, the phenomena of the phase separation of the ternary PVDF/DPC/DPK system was investigated and the phase separation happened from liquid-liquid phase separation to solid-liquid phase separation with decreasing the mass ratio of DPC to DPK. The membrane with higher ratio of DPC to DPK has higher water permeability, whereas, the tensile strength holds almost unchanged. The pressured and submerged modules of the PVDF membranes were designed for the individual deep treatments of sewage and wastewater. The pilot tests showed the excellent performance of the membranes. It is proud that there is near zero effluents in the production of PVDF MF membranes since DPC and DPK are undissolvable in water and circularly utilized with the help of a series of unit operations such as extreation, simple distilation, sedimentation and dry processes.