Manipulating Membrane Anti-Wetting Tendency Through Phase Inversion

Membrane distillation (MD) is a separation technology which liquid feed phase and liquid permeate phase are in direct contact with a microporous hydrophobic membrane and the separation occurs based on the thermodynamic equilibrium at the liquid-vapour interface. In MD, the vapour pressure difference is the driving force to drive the water vapour transport across the membrane. An ideal MD membrane has the characteristics of high permeate flux and rejection percentage, with an excellent anti-wetting tendency. In this study, the morphology of PVDF membrane fabricated at different phase separation parameters (casting platform temperature and dope solution temperature) was analysed as it is believed that the morphology will be affected by the casting parameters which in turn influence the membrane wetting resistance. From our findings, manipulating of dope solution temperature has a more overall effect on membrane morphology instead of casting platform temperature. 60 ℃ dope solution temperature able to produce the membrane with enhanced hydrophobicity with largest contact angle at 143.36˚ while 90 ℃ dope solution results in membrane with highest average permeate (19.72 kg/m2h) flux and perfect rejection rate (100%) when running DCMD at a hot and cold temperatures of 60 ℃ and 20℃ and this highest flux is mainly due to its least membrane thickness. Based on the SEM images, the gain on the contact angle is related to the more formation of nano-scale spherical globules and the uniformity of spherical globules distribution at membrane surface (membrane-glass plate interface) for membrane prepared at 60 ℃ dope solution temperature