Excellent performance for water purification achieved by activated porous boron nitride nanosheets

Adsorption represents an efficient and economical approach for water purification. Strong efforts have been made to try new adsorption materials. In this study, activated oxygen-rich porous boron nitride nanosheets (OBNNSs) containing abundant BO bonds and boron atom vacancies were facilely synthesized via simple two-step method. Different from the conventional doping and activation methods, the oxygen dopants and boron atom vacancies in OBNNSs mainly originate from the starting materials and are introduced in situ and chemical activation during the product formation. OBNNSs exhibit high adsorption capacity and adsorption rate for metallic ions due to its unique polarity of BO bonds and boron atom vacancies, surpassing the bulk and activated BN as well as many common adsorbents. Their critical role in the strong adsorption ability of OBNNSs was validated by theoretical calculations. Additionally, the two-dimensional nanostructure of OBNNSs makes most of the BO bonds and boron atom vacancies expose on the surface ((002) plane) and further enhances the adsorption performance. Moreover, the used OBNNSs can be readily regenerated by acidic elution due to the super anti-oxidation, corrosion resistance, and structural stability. Bearing both a high removal efficiency for water pollutants, especially different toxic metallic irons (Pb2+, Cr3+, and Hg2+), and excellent reusability, OBNNSs are very promising nanomaterials for water purification.