Highly selective and rapid sequential degradation of venlafaxine-class antidepressants using a novel BiOCl-based two-dimensional molecularly imprinted photocatalyst

Abstract

Photocatalytic degradation is an effective technology for the removal of organic compounds. However, the lack of selectivity limits its practical application for harmful substances in complex systems. Herein, a novel molecularly imprinted photocatalyst (MI-BiOCl) was prepared using two-dimensional nanosheet BiOCl as a matrix. Based on the superior degradation activity and charge carrier transfer of BiOCl, along with an imprinting layer with selectivity, MI-BiOCl can selectively adsorb and rapidly and sequentially degrade venlafaxine (VEN) and its analogue fluoxetine (FLU) in mixtures. MI-BiOCl can adsorb 32.27 mg/g of VEN within 5 min, with an imprinting factor of 4.72. Within pH range of 3–9, the degradation efficiency of VEN by MI-BiOCl remained above 98.8 %, unaffected by coexisting humic acid, and after four cycles, it was still higher than 98 %. Moreover, over 88.8 % of VEN and 99.3 % of FLU in municipal wastewater were degraded by MI-BiOCl, and the degradation intermediates tended to be non-toxic. DFT simulations verified that the highly selective degradation was due to the synergistic effect of imprinting sites, catalytic active sites and non-covalent bonding forces including van der Waals, hydrogen bonding and electrostatic interaction between MI-BiOCl and VEN and FLU. FLU, with stronger binding affinity, has the advantage of being preferentially degraded. The strategy provides a method for the highly selective degradation of drug pollutants in complex media.