Calcination of layered double hydroxide membrane with enhanced nanofiltration performance

Two-dimensional layered double hydroxides (LDH) as a membrane material has tremendous potential in the water treatment field. However, the stability and permeance of the LDH membrane should be further improved for the industrial application. In this study, the LDH separation layer was in situ grown on the tubular Al2O3 substrate. The obtained LDH composite membrane was then calcined to reduce the surface free energy and remove some interlayer anions. Therefore, the calcined LDH composite membrane exhibited enhanced stability and permeance for removing dye molecules from water. The permeance of the calcined LDH membrane reached 367 Lm(-2)h(-1)MPa(-1) and the rejection for Eriochrome black T was still above 99%. Moreover, the membrane can maintain the separation performance more than 110 h in the nanofiltration process. The morphologies and structures of the LDH membranes before and after calcination were also investigated. The results indicated that this facile method is effective to improve the separation performance of the LDH membrane. (C) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.