Increasing the performance of vacuum membrane distillation using micro-structured hydrophobic aluminum hollow fiber membranes

Abstract

This study develops a micro-structured hydrophobic alumina hollow fiber with a high permeate flux of 60 Lm-2h-1 and salt rejection over 99.9% in a vacuum membrane distillation process. The fiber is fabricated by phase inversion and sintering, and then modified with fluoroalkylsilanes to render it hydrophobic. The influence of the sintering temperature and feeding temperature in membrane distillation (MD) on the characteristics of the fiber and MD performance are investigated. The vacuum membrane distillation uses 3.5 wt% NaCl aqueous solution at 70 °C at 0.03 bar. The permeate flux of 60 Lm-2h-1 is the highest, compared with reported data and is higher than that for polymeric hollow fiber membranes.