Mechanically Exfoliated Few-Layer h-BN Nanosheets for Advanced Nanoporous PMMA Membranes in Water Treatment

Boron nitride nanosheets are 2D materials with high thermal conductivity, chemical stability, and electrical insulation, which are ideal for thermal management and advanced electronic devices. Herein, we employed a high-energy milling system having strategically selected ball size (25 mm: 20 mm: 10 mm = 3:4:10) to produce large-scale few-layer boron nitride nanosheets (FL-BNNSs) without the use of added chemicals. The effects of the selected ball size and prolonged milling on the surface morphology of the nanosheets were systematically examined by using advanced microscopic and spectroscopic techniques. The synthesized FL-BNNSs were uniformly dispersed in poly(methyl methacrylate) using a dichloromethane solvent by probe sonication. Ultrathin nanoporous membranes were subsequently fabricated instead of the nanofibrous morphology by using an electrospinning device and extensively characterized using a range of analytical tools. As fabricated, the PMMA-BNNS composite film was used for water purification with a simple energy-efficient filtration method and the quality of water was analyzed through various water testing parameters. This green and scalable approach for producing FL-BNNSs, followed by their potential application in water remediation, represents a sustainable pathway in materials processing and nanotechnology. Water purification results using the developed membranes pave the way for developing simple devices for environmental applications.