Effect of Nanoparticles on Thin-film Composite Membrane Surface Morphology and Productivity

To evaluate the significance of thin-film composite membrane surface morphology on water productivity, flat-sheet experiments were conducted with silicon dioxide, titanium dioxide, and cerium dioxide nanoparticles. The polyamide thin-film active layer exhibited a valley and ridge morphology that was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother cellulose acetate membrane surfaces. Reverse osmosis and nanofiltration membrane flux decline was not affected by particle type when the feed water was laboratory grade water; however, when pretreated diluted seawater measuring 4800 μS/cm served as feed water it was found that cerium oxide addition resulted in the least observable flux decline, followed by silicon dioxide and titanium dioxide.