Tannic acid non-covalent functionalized two-dimensional h-BN membrane for efficient water filtration

Abstract

Tannic acid (TA) non-covalent functionalized hexagonal boron nitride (h-BN) two-dimensional (2D) membrane (TA/h-BN) was developed by π-π interaction between h-BN and TA. The π-π interaction between h-BN and TA eliminated the agglomeration of h-BN nanosheets because of strong Van der Waals' force, and TA/h-BN nanosheets showed improved membrane forming ability. Separation performance of h-BN membrane was improved significantly after the TA non-covalent functionalization on h-BN nanosheets. TA/h-BN membrane with a thickness of 650 nm presented a water permeance of 600 L m−2 h−1 bar−1 and a rejection rate of 91 % for Congo red (CR). Moreover, prepressed TA/h-BN membrane with a thickness of 1150 nm under 3 bar for 7 h could remove 90 % of [Fe(CN)6]3-, and this prepressed membrane exhibited excellent stability during a 72 h of cross-flow filtration, suggesting its broad application prospects in water filtration.