Thin film composite membranes on ceramic for pervaporation dehydration of isopropanol

We have developed novel thin film composite (TFC) membranes on ceramic substrates (referred as ceramic TFC membranes thereafter) for pervaporation dehydration of isopropanol (IPA) by using interfacial polymerization (IP) of m-phenylenediamine (MPD) and trymesoylchoride (TMC) to create ultra-thin polyamide films as selective layers. Prior to IP, a gutter layer of polydopamine (PDA) or polyethyleneimine (PEI) was deposited on α-alumina ceramic surfaces to improve the adhesion of polyamide thin films onto the ceramic. It was found that the PEI-coated ceramic substrate provided better adhesion with the polyamide thin film than the original and PDA-coated ones owing to its smoother surface. Polydimethylsiloxane (PDMS) was employed to seal defects on ceramic TFC membranes and significantly improved the performance of pervaporation dehydration of IPA with a flux of 6.05 kg/m2 h and a separation factor 1396 at 80 °C. Moreover, the developed ceramic TFC membrane shows high stability after 120 h operation. Positron annihilation spectroscopy (PAS) analyses revealed that the newly developed membrane has an ultrathin polyamide layer of 79 nm and a PDMS coating of ~26 nm. This study demonstrates the promising application of ceramic TFC membranes for pervaporation dehydration of organic solutions.