[Degradation of Dye Rhodamine B by Solar Thermally Activated Persulfate].

In advanced oxidation technology based on sulfate radicals, thermal activation is one of the most effective methods for persulfate (PS) activation, with broad application potential for the use of solar energy to activate PS to degrade pollutants. In this study, the efficiency and mechanism of degradation of rhodamine B by solar thermally activated PS were investigated using a solar collector reactor. The effects of solar irradiation intensity, PS concentration, substrate concentration, initial pH of the solution, and background water quality on the degradation efficiency of rhodamine B were examined. The results show that the solar thermally activated PS system has outstanding oxidation degradation performance with respect to organic pollutants. The removal rate and mineralization rate of rhodamine B reached 94% and 60%, respectively, after a 120 min reaction time. The treatment efficiency of the system was notably affected by the solar radiation intensity, with performance ranked in the order sunny days > cloudy days > rainy days. The treatment efficiency of the system could be significantly improved by increasing the concentration of PS or reducing the initial concentration of the substrate, and by adjusting the initial pH of the solution to neutral. SO·and·OH are the main active oxidants in the reaction system, and·OH plays a major role in the degradation process.