Ultrahigh-permeance functionalized boron nitride membrane for nanoconfined heterogeneous catalysis

Abstract

Practical applications of heterogeneous advanced oxidation processes for organic pollutant destruction remain elusive due to poor yield of reactive oxygen species (ROS) as well as their ultrashort lifetimes and mass transfer limitations. To address these issues, nanoconfined catalysis, whereby improved reaction efficiency is attained due to rapid mass transfer, has recently gained traction in environmental remediation. Here, we introduce a simple concept of functionalizing the boron nitride nanosheet (BNNS) membrane, involving nucleation of cobalt nanocatalysts within the membrane intralayer network of water transport nanochannels. Membrane-confined crystalline reactive species with multiple exposed active sites spontaneously activate peroxymonosulfate, producing ROS for ultrafast (∼80 ms) destruction of organic pollutants at a fast flow rate of 548 L m −2 h −1 . Co-BNNS membrane showed good stability and outperformed previously developed membrane-confined catalysis systems (up to 26-fold higher permeance). Co-BNNS membrane enabled ultrafast destruction of several organic pollutants, offering an attractive alternative for membrane-based catalysis applications. • Cobalt nanocatalysts are grown in boron nitride membrane for heterogeneous catalysis • Analyses confirmed the membrane-confined growth of α-Co(OH) 2 and Co 3 O 4 crystals • Catalysis performance of membrane is explained both theoretically and experimentally • Functionalized membrane can achieve rapid destruction of organic pollutants in 80 ms Water pollution is mainly caused by anthropogenic activities and could disrupt the smooth functioning of economic activities and human health. In this context, detection of persistent organic pollutants, such as pharmaceutical and pesticides, in freshwater bodies is alarming due to their well-documented harmful impacts on human health (e.g., genetic malformations) after prolonged exposure. Due to these severe consequences, clean water (SDG6) and good health (SDG3) are included in the UN sustainable development goals. Herein, we developed a compact platform by combining a membrane separation process and advanced oxidation process in a single step for nanoconfined heterogeneous catalysis of persistent organic pollutants to produce clean water. The in situ functionalization strategy presented here is convenient and allows nucleation of nanocatalysts within the water transport nanochannels of boron nitride membrane, opening a promising avenue for the construction of catalytic membranes. We present an in situ approach of functionalizing the intralayer nanochannels of 2D boron nitride membrane, which allows simultaneous confinement of nanocatalysts, ROS species, and fluids within the intralayer for ultrafast organic pollutant destruction. Compared with conventional AOP reactors, the functionalized boron nitride membrane can be operated in a continuous-flow mode at an ultrahigh water permeance, which would allow its widespread application in water treatment.