The 11th International Conference on Water Resource and Environment (WRE 2025)

Abstract: As a promising thermally driven separation process, membrane distillation (MD) is capable of treating challenging wastewaters. However, membrane fouling, and low thermal utilization efficiency of membrane modules limited the application of MD technology in large-scale wastewater treatment. To tackle these key challenges, a novel anti-wetting and anti-fouling multifunctional Janus membrane was developed at lab scale and successfully scaled up for industrial mass production via a two-step electrospray strategy. The resultant composite structure presented high omniphobicity (water contact angle of omniphobic sub-surface was 159.3±1.1°) and underwater superoleophobicity (underwater oil contact angle of hydrophilic top surface was 152.7±0.5°). During continuous MD treatment for emulsified oily hypersaline solution, the Janus membrane exhibited stable permeate flux (10 L/m2h) and salt rejection (around 100%). To optimize the system performance, a vacuum-air gap membrane distillation (V-AGMD) module was designed and evaluated through computational fluid dynamics (CFD) simulation. The membrane module with finned air-gap cooling plate increased the flux by 16.5% compared to the module with flat air-gap cooling plate under extreme experimental conditions. Additionally, the gain-output ratio (GOR) and temperature polarization coefficient (TPC) were improved by 12% and 8%, respectively. CFD results show that fins achieve condensation efficiency enhancement by increasing the heat transfer area, breaking the boundary layer, and promoting turbulence. Based on these insights, the fabricated membrane and module were used to treat the concentrated landfill leachate, with particular focus on effects of different pretreatment methods on MD process. It was found that coagulation pretreatment could significantly reduce membrane fouling through removal of hydrophobic humic acids and aromatic organics. The hybrid Coagulation-Membrane Distillation process can reduce the discharge of concentrated landfill leachate by 80%, while ensuring that the produced water met the emission standards.

Biography: Prof. De-Yin Hou is the deputy director of National Engineering Research Center, he obtained his Ph.D. in Environmental Engineering from Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences in 2010. Dr. Hou’s research focuses on membrane separation technology, wastewater treatment and resource recovery. Dr. Hou has published more than 100 research articles in international journals and applied for more than 30 invention patents. His research and development in membrane distillation technology has received two science and technology awards. In recent years, Dr. Hou has developed a series of superwetting membrane materials, such as superhydrophobic membranes and superhydrophilic membranes, and has achieved industrial production and application demonstration. Dr. Hou also developed high-efficiency membrane distillation equipment for concentrating high-salinity wastewater, which has been applied in landfill leachate treatment, coal chemical wastewater concentration, and desulfurization wastewater treatment.