Functionalized ceramic nanofilter for wastewater treatment by coupling membrane separation and catalytic ozonation

Micropollutants elimination in water becomes a global concern and represents an important issue for a possible reuse or a release to the environment. Hybrid processes combining membrane filtration and catalytic ozonation offer promising opportunities for micropollutant removal. A ceramic commercial nanofilter with a very low molecular weight cut-off of 200 Da was functionalized by sol-gel deposition of a mesoporous maghemite (gamma-Fe2O3) thin layer. Preliminary experiments enabled to determine the maximum temperature usable for the thermal strengthening of the catalytic layer without significant permeance change. The catalytic activity of the iron oxide equivalent powder was tested in batch reactor with ozone and para-chlorobenzoic acid (pCBA) which quickly reacts with hydroxyl radicals formed with ozone at the catalyst surface, and only very slowly with ozone itself. The operational performance of the functionalized ceramic membrane was evaluated in a dedicated pilot. The obtained results unequivocally show the catalytic activity of this functionalized membrane.