Efficient and eco-friendly preparation of hydrophilic boron nitride nanosheets for enhanced filtration properties

Abstract The exceptional properties of boron nitride nanosheets (BNNSs) render them promising for diverse applications. Nevertheless, the obstacles of effectively readying them and their restricted ability to disperse in liquids are current constraints. In this study, a simple and efficient glucose-assisted mechanochemical exfoliation method was developed to achieve simultaneous exfoliation and functionalization of BNNSs. The BNNSs yield reached 87.5%, featuring grafted hydroxyl groups at the edges and well dispersed in water. Furthermore, the prepared BNNSs were dispersed into water and subsequently incorporated into a nanofiltration membrane using vacuum filtration. The vacuum filtration produced the BNNSs nanofiltration membrane with high water flux and flexibility interception rate due to its excellent dispersibility. The optimal interception rate of the BNNSs filter membrane for a 2 mg·ml⁻¹ Congo red (CR) solution was 96.12%, and the optimal flux of the BNNSs filter membrane for pure water was 1312 l·m⁻²·h⁻¹·bar-¹ according to the experiments. Additionally, the adsorption performance of BNNSs with different functionalized groups (e.g. hydroxyl and amino) for CR and heavy metal ions (copper ions) was studied through density functional theory theoretical calculations. This study not only present a highly efficient, environmentally friendly, and cost-effective method for preparing hydrophilic BNNSs to enhance their yield, but also investigated and predicted the interception rate and flux of BNNSs nanofiltration membranes functionalized with different functional groups for water contaminated with metal ions and dyes.