Fabricating PVDF hollow fiber microfiltration membrane with a tenon-connection structure via the thermally induced phase separation process to enhance strength and permeability

In this work, thermally induced phase separation (TIPS) method was adopted to manufacture polyvinylidene fluoride (PVDF) blend hollow fiber microfiltration membrane with tenon-connection structure, which is used to fasten in Chinese traditional building by the stronger friction between rabbet and mortise, for water treatment by blending polyvinyl butyral (PVB). In this microstructure formation process, the distribution of PVB within the matrix and its regulatory role were investigated. Especially, the comprehensive effect of rabbeting and PVB adhesion on strength (The maximum breaking strength reached 17.08 MPa) was discussed. The results showed that a suitable PVB will markedly reduce the thickness of skin-layer close to the outside surface even for the solid-liquid (S-L) phase separation while the excessive PVB result in a thick skin-layer. Besides the strength, PVB markedly improved the hydrophilicity and permeability of the membrane. The breaking strength is more than 8 MPa, the maximum pure water flux is as high as 929.23 Lm(-2)h(-1) and the rejection rate of carbon particles is nearly 100% even the polymer content is only 22%. In addition, the membrane showed a beta-phase and an improved anti-fouling capacity. The investigation presented a simple way to regulate microstructure, enhance mechanical strength, flux and anti-fouling capacity of the membrane via the TIPS process for water treatment.