Polyamide-Imide Membranes with Surface Immobilized Cyclodextrin for Butanol Isomer Separation via Pervaporation

A novel cyclodextrin (CD) derivative, m-xylenediamine-beta-cyclodextrin (m-XDA-beta-CD), has been synthesized and used to graft beta-CD on membrane surface for the pervaporation separation of butanol isomers. The reaction mechanisms for the m-XDA-beta-CD synthesis and the membrane surface grafting are confirmed by FTIR and TGA. The as-fabricated novel CD-grafted polyamide-imide (PAI) membranes show homogeneous morphology and significant improved separation performance as compared to the unmodified PAI membranes and PAI/CD mixed matrix membranes made of physical blends. The effects of chemical modification time and dope concentration on the asymmetric membrane have been studied. The optimal separation performance can be found with the CD-grafted PAI membrane cast from a 22 wt % dope concentration, which exhibits a total butanol flux of 15 g/m(2)/h and a separation factor of 2.03. This newly developed membrane with surface-immobilized CD may open new perspective for the development of next-generation high-performance pervaporation membranes for liquid separations. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 1470-1484, 2011