(31d) Pervaporation through Microporous Membranes

Separation processes play critical roles in manufacturing and their proper application can significantly reduce costs and increase profits. Alternative energy-saving and high efficiency separation process are strongly expected to be applied to many industries. Membrane separation appears to be a promising candidate because of low energy consumption, compact unit, simple operation and low environmental impact. Therefore, strong interest exists in the synthesis of membranes that exhibit both higher permeabilities and higher selectivities than presently available polymers. In this report, our recent pervaporation results through microporous membranes such as zeolite and carbon membranes. The performance of the microporous membranes is far superior to any other membrane previously reported in both of pervaporation and vapor permeation. Recently, A type and T type zeolite membrane modules have been put to practical use for dehydration of organic liquids. Although azeotropic distillation and extractive distillation are presently used for azeotropic mixture, these processes suffer from complexity and high energy consumption. Zeolite membrane is a promising candidate for a pervaporation membrane because of their high permselectivity and high thermal stability. Carbon membranes derived from a precursor polymer by pyrolysis also showed a high selectivity for the pervaporation and vapor permeation. High permselectivity of the membrane can be attributed to the molecular sieving effect of microporous membranes.