Efficient Fe(III) reduction and persulfate activation induced by ligand-to-metal charge transfer under visible light enhances degradation of organics

[Display omitted] •A novel heterogeneous Fenton-like process driven by visible light is proposed.•Reactivity is strongly enhanced without the use of reducing agents and TiO2 modification.•Fe(III) reduction for PS activation can be accomplished via LMCT in organic-TiO2-Fe(III).•It can be operated at low iron dosage and neutral conditions against Fenton system.•The excellent and long-lasting catalytic performance is mediated via synergistic effect. Efficient transformation of Fe(III) to Fe(II) enhances the efficiency of persulfate-based Fenton-like process (e.g., Fe(II)-PS system). Here, we developed a novel heterogeneous Fenton-like system driven by visible light (organic-Fe(III)-PS-TiO2-Vis) for effective reduction of Fe(III), activation of PS and degradation of organic pollutants without the need for external reducing agents or modifications in TiO2. The visible light-induced ligand-to-metal (organic-to-TiO2) charge transfer (LMCT) remarkably boosting Fe(III) reduction to increase reactive oxygen species (ROS) via PS activation, and further enhanced the self-degradation and mineralization of various organics, including phenolics (bisphenol A and phenol), antibiotics (ibuprofen and tetracycline), and dyes (methylene bule and rhodamine B). Compared with traditional Fe(II)-PS and Fe(II)–H2O2 systems, the organic-Fe(III)-PS-TiO2-Vis process requires a lower dosage of iron salt. The effective pH range has been broadened to neutral conditions due to effective prevention of Fe(III) precipitation and rapid circulation of Fe(III)/Fe(II). The comprehensive mechanistic study indicated that a synergistic effect was generated via Fe(III) reduction, PS activation, ROS generation and organic decomposition, resulting in sustainable and excellent catalytic performance of this novel Fenton-like process. Further, the results of cycling experiments and tests involving real industrial wastewater highlight the enormous potential of the proposed LMCT-mediated heterogeneous Fenton-like process in environmental remediation.