Fabrication, optimization, and performance of a novel double-skinned Al2O3.TiO2 ceramic nanocomposite membrane for forward osmosis application

Abstract

Abstract In this study, a thin film nanocomposite ceramic membrane with an Al2O3 substrate and TiO2 as the thin film active layer was fabricated via dip coating technique and optimized for application in FO purification of groundwater. The effect of parameters including sol aging, calcination temperature, and dip time was investigated. Based on the results, the least water flux was obtained during 6 h after sol preparation. Furthermore, boosting the synthesis temperature and dip time led to flux reduction. According to the optimization results, 6.75 h sol aging, 17.00 s dip time and a 319 °C calcination temperature, led to the maximal water flux of 168 L/m2 h bar and 48% salt rejection. In addition, by covering the substrate with 10 layers of TiO2, water flux was reduced to 10.82 L/m2 h bar. FO process using MgCl2 solution (2 M) as draw and DI water as feed solutions, resulted in an initial water flux of 17.04 L.m−2 h−1 (LMH). Replacing DI water with a 0.01 M NaCl solution as feed, the initial water flux was decreased to 15.5 LMH. Also, using groundwater as the feed solution with an EC of 1407, 14.1 LMH initial water flux was obtained.