Highly Stable Hydrophobic SiNCO Nanoparticle-Modified Silicon Nitride Membrane for Zero-Discharge Water Desalination

Membrane distillation water desalination can attain a significantly higher water recovery than reverse osmosis, while the lack of stable hydrophobic membranes limits its commercial applications. This article presents the preparation of a new hydrophobic membrane by modifying a porous Si3N4 substrate with vesicular SiNCO nano-particles. The membrane had a water contact angle of 1428, due to the presence of -Si-CH3 terminal groups and the high surface roughness. The contact angle remained nearly the same after exposures of the membrane to boiling water, aqueous solutions with pH ranging from 2 to 12, and benzene. The membrane exhibited satisfactory water desalination performance on highly concentrated NaCl solutions and simulated seawater. With the highly stable membrane, it is promising to develop a zero-discharge water desalination process for simultaneous production of fresh water for daily uses and brine for industrial uses. (C) 2016 American Institute of Chemical Engineers AIChE J, 63: 1272-1277, 2017