Preparation, characterization of PPS micro-porous membranes and their excellent performance in vacuum membrane distillation

Polyphenylene sulfide (PPS) hydrophobic micro-porous flat sheet membranes were fabricated with diphenyl ketone (DPK) and benzoin (BZ) as mixed diluent via thermally induced phase separation (TIPS). It was found that the mass ratio of DPK/BZ had a strong influence on the structure and property of PPS membranes. As DPK content increased, the interaction between PPS and diluents reduced linearly and the membrane micro-structures changed from honeycomb, bi-continuous to spherical particle structure via liquid-liquid (L-L) phase separation process. Herein, the prepared PPS micro-porous membranes were used in vacuum membrane distillation (VMD) for the first time, and they showed the strong hydrophobicity and high salt rejection ratio. Especially, the membrane prepared from the mixed diluent of 15 wt% DPK and 85 wt% BZ with the bi-continuous network structure and Berberis thunbergii var. atropurpurea Chenault leaf-like structure achieved the maximum permeate flux of 22.8 L/m(-2) h(-1) and the highest salt rejection of 99.99%. Most importantly, the membrane with Berberis thunbergii var. atropurpurea Chenault leaf-like leaf structure performed excellent long-term stability in corrosive water membrane distillation (MD) experiment (3.5 wt% NaCl and 10 wt% NaOH as feed solution). Those results show the potential application of this novel type of membrane in the treatment of corrosive sewage.