Understanding Wetting and Rejection in Membrane Distillation for High Recovery Treatment of High-Salinity Streams

Membrane distillation (MD) is a thermally driven process that can be used to extract distillate-quality water from highconcentration streams using waste heat and/or solar thermal energy. To achieve near-100% rejection of solutes, MD relies on an hydrophobic, unwetted membrane. This presentation investigates the long-term (100-day) wetting resistance of hydrophobic MD membranes and the wetting behavior of conventional and novel MD membranes with high-concentration feed streams, as may be present in concentrate recovery systems and in applications approaching zero liquid discharge (ZLD). This research provides fundamental insight into wetting mechanisms relevant to MD membrane design for high-recovery treatment applications.