Development of hydrophobic polymethylhydrosiloxane/tetraethylorthosilicate (PMHS/TEOS) hybrid coating on ceramic membrane for desalination via membrane distillation

This study presents a facile approach to produce hydrophobic ceramic hollow fiber membranes (CHFMs) for membrane distillation (MD) desalination using the polymethylhydrosiloxane/tetraethylorthosilicate (PMHS/TEOS) hybrid material. The CHFM was modified via dip-coating with PMHS/TEOS hybrid solution followed by post-coating spinning to facilitate the formation of pores on the coating layer. The effects of ethanol and PMHS concentrations on the coating layer structure and hydrophobicity of the membranes were studied. CHFMs acquired hydrophobic properties after surface modification with the water contact angle values in the range of 108.2° to 124.1°. These membranes showed outstanding direct contact MD (DCMD) desalination performance with salt rejections of >99.98%. A flux of 6.7 L/m2h was achieved by the surface-modified CHFM when treating feed solution with a salinity of 35,000 ppm.