Superhydrophobic alumina hollow ceramic membrane modi fi ed by TiO2 nanorod array for vacuum membrane distillation

Abstract

Problematic fouling along with wetting of membrane represent the main barriers for large-scale application of this technology. To solve the above problems and reinforce the anti-pollution and anti-wetting features of the distilling membrane, a brand-new TiO2 nanorods and 1H,1H,2H,2H-perfluorodecylsilane-triethoxy (PDTS) modified alumina hollow ceramic membrane with superhydrophobic surface and self-cleaning property was prepared for utilization in the vacuum membrane distillation. To synthesize the novel membrane, a seed layer was supported on the hollow ceramic membrane by the immersion-calcination method. Then, the TiO2 nanorods were grown on the membrane by hydrothermal method and annealed to strengthen the crystal structure. Finally, the nanorod-grown membrane was immersed in an alcohol solution of PDTS for hydrophobic treatment. The resulted modified membrane was applied to the distillation process to treat 100 g L-1 of concentrated brine for 3 h. It was revealed that the modified membrane possessed with a lower ionic conductivity under 20 mu s.cm(-1) of the permeated liquid and desirable surface superhydrophobicity at appropriate water contact angle of 152 degrees, thus showing great promise for use in the membrane distillation process. (c) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.