Degradation Rhodamine B dye wastewater by sulfate radical-based visible light-fenton mediated by LaFeO3: Reaction mechanism and empirical modeling

Abstract

In this work, a novel sulfate radical (SR)-visible light-Fenton mediated by LaFeO3 (LFO) under visible light was established and its performance on Rhodamine B (RhB) dye wastewater degradation was evaluated. Herein, peroxymonosulfate (PMS) was able to be activated by a synergic effect of visible light energy and LFO to form SR and hydroxyl radical (·OH). All RhB (initial concentration was 20 mg L−1) degradation was reached at 180 min under visible light irradiation in the presence of 3.552 mM PMS and 1.0 g L−1 LFO. All reactions followed the observed pseudo-first order reaction kinetics, including effects of [PMS], [catalyst], optical power density and initial solution pH. Based on the investigation of above parameters effects on RhB degradation in SR-photo-Fenton, a predictable and empirical mathematical kinetic model was proposed. Additionally, the reactive oxygen species (ROS) formed in this SR-visible light-Fenton were identified by quenching experiments, as that SO4−· and ·OH dominated oxidation. At last, the reaction mechanism of this novel SR-visible light-Fenton was suggested based on the qualitative/quantitative analysis of major intermediates of RhB and the identified ROS in SR-visible light-Fenton mediated by LFO.