A superhydrophilic C-hBN catalytic layer to boost water flux and enable in-situ cleaning for membrane distillation via selective peroxymonosulfate oxidization

A superhydrophilic C-hBN layer was coated on PVDF membrane via PVA-CNT crosslinking. • The membrane has notable flux increase and rapid PMS activation for fouling control. • Enhanced flux was due to the increased heat unitization efficiency of C-hBN layer. • PMS was priorly adsorbed to generate singlet oxygen for selective organic removal. • The membrane is able to reduce heat and mass transfer resistance simultaneously. How to get membranes with high water flux and sustainable long-term operation remains a key challenge for membrane distillation (MD) in treating high-salinity organic wastewater. Herein, a novel carbon-doped hexagonal boron nitride (C-hBN) catalytic membrane was developed to boost water flux and enable in-situ cleaning for membrane distillation via selective peroxymonosulfate (PMS) oxidization. Experimental results showed that the membrane achieved a 28.3% increase in water flux and an 83.8% reduction in flux decline rate. The numerical COMSOL simulations and membrane surface calculation using heat and mass transfer equations revealed that the enhanced flux was mainly attributed to the increased heat unitization efficiency during water evaporation in superhydrophilic C-hBN layer. Density functional theory (DFT) calculations and electron paramagnetic resonance (EPR) indicated that C-hBN exhibited a strong interaction with PMS, and 1 O 2 was selectively generated, leading to the efficient organic removal in high salinity environment. This study offers a viable pathway to engineer high-performance, in-situ cleaning membranes for sustainable operation of membrane distillation. Download: Download high-res image (194KB) Download: Download full-size image