Characterization of PVDF hollow fiber membrane

Abstract

Physical properties of the membranes are the keys to the greater performance of the membrane. Fabrication parameters and conditions were factors to affecting the characteristic of the membrane. In this report, post treatment annealing temperature, variation of fabricating conditions together with additional additives to the membranes were investigated. Two fabrication techniques - Non-Solvent Induced Phase Separation (NIPS) and Thermal Induced Phase Separation (TIPS) were exploited for membranes fabrications. Five tests were carried out on NIPS and TIPS membranes to better understand selectivity, permeability and crystallization morphology of the PVDF membranes.

With annealing process on NIPS membranes, the membranes showed to have increased in selectivity and decreased of flux rate as membrane’s substrate nucleated under heat treatment. Dominating crystallographic of α phase was also observed which leaded to thermal stability of the membranes.

The extruding temperature different for TIPS membranes had been observed to have same level of selectivity but permeability level increased as the extruding temperature increased. The increase of extruding at a higher temperature leaded to a growth of γ phase. Experimental results had also shown that with addictive of zinc to TIPS membranes; it would decrease the selectivity but increase the flux rate. Addition of α and γ phase crystals were formed and in dominant.

Therefore from the experiments conducted, increase of the selectivity would lead to decrease of permeability or vice versa. Annealing treatment had increased the selectivity for NIPS membrane and different extruding temperature and zinc additives leads to higher permeability of membranes. Crystallization morphology of PVDF only allowed a better understanding of the membrane’s material but did not have a direct physical relation to the membrane properties.