Effective photocatalytic degradation of paracetamol using La-doped ZnO photocatalyst under visible light irradiation

Visible light-driven photocatalysts of lanthanum (La) doped ZnO nanoparticles were successfully prepared by a facile precipitation method using various La doping concentrations (0.5,1.0 and 1.5 wt%). La doping did not modify the crystallinity of ZnO significantly, but enhanced the optical absorption of visible light due to the reduction in particle size and band gap energy. La-doped ZnO photocatalysts were applied to treat 100 mg/L paracetamol in aqueous solution under visible light irradiation after 3 h. 1.0 wt% La doped ZnO photocatalyst showed the highest photocatalytic activity for the degradation of paracetamol with a degradation efficiency of 99% and TOC removal of 85%. Based on the chemical analysis of photocatalytic products detected, proposed mechanism for paracetamol removal by La-doped ZnO nanoparticles under visible light illumination including radical generation with use of photocatalytic degradation and subsequent reaction pathways was proposed. (C) 2017 Elsevier Ltd. All rights reserved.