Performance enhancement of a polydimethylsiloxane membrane for effective n -butanol pervaporation by bonding multi-silyl-functional MCM-41.

In the current work, MCM-41/polydimethylsiloxane (PDMS) mixed matrix membrane (MMM) was prepared for effective n -butanol pervaporation from a model aqueous solution. In order to improve the compatibility between MCM-41 and PDMS, different types of silane coupling agents including n -propyltrimethoxysilane (PTMS), n -octyltrimethoxysilane (OTMS), n -dodecyltrimethoxysilane (DTMS) and n -hexadecyltrimethoxysilane (HDTMS) were used to modify the MCM-41. The results showed that the highest n -butanol separation performance was achieved by bonding 20 wt% of PTMS-modified MCM-41 with PDMS. Under these conditions, total flux of 1476 g m -2 h -1 was obtained when separating a 1.5 wt% n -butanol aqueous solution at 55 °C. The total flux increased by nearly 40% compared to the pure PDMS membrane with no obvious changes of the n -butanol separation factor at the same time. The curing process of the casting solution was also significantly improved after MCM-41 modification.