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 142°, 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. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1272–1277, 2017