Nanofibrous Composite Membranes for Membrane Distillation

Abstract

Membrane distillation (MD) is a thermally driven membrane process, in which water vapor and volatile molecules evaporate at the liquid/vapor interface in the hot feed side of the membrane. They then transport through the microporous hydrophobic membrane, and finally condense in the cold permeate side. The unique features of electrospun nanofibrous membranes (ENMs), including high surface hydrophobicity, high porosity and easy incorporation of nanomaterials, make them highly attractive for MD applications. This chapter aims to review the state-of-art fabrication and modification of ENMs for MD processes. Specifically, four basic MD configurations and novel MD hybrid membrane processes are discussed, followed by the elaboration of intrinsic requirements of MD membranes. Next, membrane material selection, post-modification and coating methods for fabricating nanofibrous MD membranes are discussed in detail. After briefly highlighting MD applications, the conclusions and perspectives for future ENMs development are identified. It is hoped that the systematic explanation presented here can acquaint the readers with the basic knowledge of MD separation mechanisms and the requirements of MD membranes. By understanding the current status of the nanofibrous composite membrane developed for MD applications, the readers can be inspired to explore more novel ENMs for MD over a broader horizon.