Preparation of PDMSvi-Al2O3 composite hollow fibre membranes for VOC recovery from waste gas streams

A new PDMSvi-Al2O3 composite hollow fibre membrane has been developed by coating a PDMSvi-oligo film on the outer surface of an Al2O3 hollow fibre porous substrate prepared by a dry/wet phase inversion method. Microstructures of the composite membranes were examined using scanning electron microscopy (SEM), displaying a uniform PDMSvi-oligo coating layer, free of defects with a thickness of around 15 μm. Such composite hollow fibre membranes are suitable for VOC recovery from waste gas streams because of their high chemical stability. The separation performances of the PDMSvi-Al2O3 composite hollow fibre membrane were studied using chloroform in N2 as a test vapour mixture. By analyzing the experimental data obtained at various conditions with a mathematical model derived, the permeabilities of chloroform and nitrogen in the PDMSvi polymer membrane were obtained. The effects of temperature, feed flow rate, vacuum pressure on the permeate side and feed concentration on the chloroform recovery were also investigated both experimentally and theoretically.