(63a) Novel Membranes, Membrane Processes and Membrane Devices

Membranes have created an alternate and expanding universe in the field of separations. I will talk first about membranes and membrane processes leading to membrane extractors, membrane contactors and membrane reactors. I will then talk about our research into various novel membranes, membrane processes and membrane devices. The novel membranes will include organic solvent nanofiltration membranes, interfacially polymerized membranes, and liquid membranes. Systems studied include biofuel separation and recovery from clarified fermentation broths, CO₂ separation, and various separations encountered in organic solvent-based systems. Next I will focus on membrane distillation for desalination, specifically our studies on direct contact membrane distillation dealing with a novel membrane structure with hydrophobic hollow fiber membranes, membrane-cross flow configuration in concentrating sea water up to 19-20% salt level with scaling salt precipitates flowing all around and recently developed larger-scale devices. I will describe in addition a novel but simple configuration for highly productive air gap membrane distillation. I will then touch on hollow fiber membrane crystallizers based on anti-solvent crystallization and cooling crystallization and their subsequent adoption to develop continuous processes for producing polymer-coated drug crystals/nanoparticles. In membrane separations we always look for highly-selective membranes to avoid multi-staging. Yet membranes in practice often have limited selectivity. The concept of internal staging in gas separation and ultrafiltration in a membrane device containing multiple membranes led to much higher selectivity than achievable otherwise with a single membrane. The conception of such structures for hollow fiber membranes was stimulated by the notion of hollow fiber contained liquid membranes developed earlier by us. I hope to provide you with a brief introduction to these developments from our laboratory in membranes and membrane separations.