Hollow Fiber Membrane Design for Membrane Distillation (MD) and MD based Hybrid processes

Abstract

Membrane Distillation (MD) is an emerging technology for seawater and brackish water desalination with ultra-high salt rejection and feasibility of utilizing low-grade waste energy. Compared with flat sheet membranes, hollow fiber membranes have relatively large specific surface areas. But the main drawback of the hollow fiber module in MD application is its low flux caused by poor flow dynamics and the resultant temperature polarization. Hence, the development of suitable hollow fiber membranes for MD process has gained great interest in recent year. In this work, the micro-morphology and macro-geometry of the hollow fiber membranes are explored and carefully designed for direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) processes. In addition, two MD based hybrid processes, namely, Freeze Desalination-Membrane Distillation (FD-MD) and Forward Osmosis-Membrane Distillation (FO-MD) are also explored for desalination and wastewater treatment.