Visible light can also efficiently activate chlorine dioxide for the abatement of micropollutants

• The visible light/chlorine dioxide system effectively degraded microcontaminants. • The degradation of ATL under different visible light wavelengths was revealed. • The established model well simulated ATL degradation and radical concentrations. • Contributions of HO • , ClO • , Cl • and O 3 to ATL degradation were revealed. • Formation of disinfection byproducts were analyzed during the Vis-LED/ClO 2 system. Advanced oxidation processes (AOPs) based on chlorine dioxide (ClO 2 ) activation via ultraviolet (UV) exist the defect of high-energy consumption. Herein, a novel visible-activated ClO 2 oxidation system (Vis-LED/ClO 2 ) was developed. Results showed that 93.04 % of atenolol (ATL) was rapidly removed by Vis 425 -LED/ClO 2 process within 20 mins. Compared with single ClO 2 or Vis 425 -LED system, the degradation rates of selected six contaminants were significantly increased in the Vis 425 -LED/ClO 2 system. Under visible light irradiation, ClO 2 decomposed into Cl − , ClO 2 − , ClO 3 − and free chlorine. Quenching and probe experiments confirmed that hydroxyl radicals (HO • ), chlorine oxide radicals (ClO • ) and chlorine radicals (Cl • ) and ozone (O 3 ) co-contributed to the degradation of ATL. The steady-state concentrations of HO • , ClO • and Cl • , as well as the average concentration of O 3 , were determined in Vis-LED/ClO 2 systems at wavelengths λ = 425, 440, 460 and 480 nm. Solution pH hardly affected the degradation of ATL, while increasing of ClO 2 concentration enhanced the ATL degradation. The established kinetic model accurately predicted ATL degradation, reactive species concentrations, and the contributions of each component in the Vis-LED/ClO 2 system. Cl – had little effect on ATL degradation, while HCO 3 – and humic acid (HA) inhibited ATL degradation by quenching reactive species. The effectiveness of the system in real water and the low risk of disinfection byproducts were also verified. This work provided an efficient and energy-saving AOPs for the elimination of contaminants, which has important implications for understanding the photolysis and transformation of ClO 2 under visible light irradiation.