Partially oxidised boron nitride as a 2D nanomaterial for nanofiltration applications.

Boron nitride (BN) based 2D nanomaterials are an emerging class of materials for the development of new membranes for nanofiltration applications. Here, we report the preparation, characterisation and testing of highly promising nanofiltration membranes produced from partially oxidised BN (BNOx) 2D nanosheets. In our work, the partial oxidation of BN was successfully achieved by heating the bulk h-BN powder in air at 1000 °C, resulting in BNOx product. The characterisation of the sample showed the presence of B-OH groups corresponding to the partial oxidisation of the BN. The BNOx material was then exfoliated in water and used to produce membranes, using vacuum filtration. These membranes were characterised using electron microscopy, BET and mercury porosimetry techniques. The membranes have also been tested in water purification and removal of several typical water-soluble dyes, demonstrating outstanding retention values close to 100%. We believe that this research opens up new opportunities for further production, as well as chemical functionalisation and modification of membranes for nanofiltration and separation technologies.