An omniphobic membrane with macro-corrugation for the treatment of real pharmaceutical wastewater via membrane distillation

Abstract

Treatment of realistic pharmaceutical wastewater with hazardous compound, complex composition and high concentration under certain scenarios is critical to environmental protection. Membrane distillation (MD) offers the potential to concentrate the wastewater, extract clean water and reduce the volume to be treated in further downstream processing. In this work, an omniphobic membrane with macro-corrugation was fabricated for MD against realistic pharmaceutical wastewater. The membrane was fabricated by electrospinning technique, followed by heat-pressing, physical compression for imprinting of patterns and omniphobic coating. The pattern was imprinted by a simple and cheap approach and can potentially be applied to larger scale applications. The as-prepared membrane showed high water contact angle (142.5 ± 2.3°), low water sliding angle (25.8 ± 3.8°) and fouling/scaling resistance in the presence of salt and surfactants. Furthermore, it demonstrated excellent stability during the concentration of challenging realistic pharmaceutical wastewater with complex composition, due to the simultaneous wetting resistance by Teflon coating and enhanced turbulence to interrupt aggregation by surface patterns. This work gives useful insights on the design and application of MD membranes for treating challenging pharmaceutical wastewater.