Interlayer-free Silica-carbon Template Membranes from Pectin and P123 for Water Desalination

Abstract

For the first time the interlayer-free silica-carbon templatesmembrane has been successfully fabricated employed pectin as carbonsource. This membrane was compared to interlayer-free silica-P123membrane that were fabricated via Rapid Thermal Processing (RTP). Theaim of this work is to investigate the performance of interlayer-free silicapectinand silica-P123 membranes. Sol-gel process has been utilised toproduce silica thin film using TEOS as precursor, EtOH, HNO 3 and NH 3 with two-step acid-based catalyst (50 °C, 3 hours). Pectin and P123 weretemplated into silica sols. Subsequently, the alumina tubular supportmembranes were dip-coated into these sols and calcined at 400 °C (pectin)and 350 °C (P123), respectively with 4 layers each membrane. Theinterlayer-free silica-pectin shows excellent water flux (5.73 kg m -2 h -1 ) incomparison to interlayer-free silica-P123 (1.449 kg m -2 h -1 ). Both silicapectinand silica-P123 membranes show very good salt rejection (>99%). The performance of silica-pectin membrane is much better than silica-P123membrane (~4 times higher). It is influenced by the length of carbonschains where carbon chains of pectin is much lower than P123. Due to that, P123 connected to silica networks create dense film of membrane andreduce the membranes performance.