The pH-dependent degradation of sulfadiazine using natural siderite activating PDS: The role of singlet oxygen

Occurring naturally siderite (FeCO3) was used as the heterogeneous catalyst to activate peroxodisulfate (PDS) for the degradation of sulfadiazine under different initial pH values. The findings of this system exhibited various ROS (e.g. O-1(2), SO center dot(-)(4) and center dot OH) present during a wide range of pH values. Among them, O-1(2) could significantly facilitate the initial degradation rate, and the increased pH enhanced the role of O-1(2). The factors including initial pH values, siderite dosage, PDS concentration, initial contaminants concentration, and water matrix were discussed. The role of each ROS was investigated through quenching test and electron paramagnetic resonance (EPR). Furthermore, the comprehensive degradation process was proposed based on the LC-MS results. And the cycle test demonstrates the reusability of siderite at a pH of 3. Accordingly, this study is of great significance for understanding the degradation of such sulfonamide pollutants in the siderite/PDS system. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, naturally occurring siderite was utilized as a heterogeneous catalyst to activate peroxodisulfate for the degradation of sulfadiazine under different initial pH values. Various reactive oxygen species (ROS) were found to be present during the degradation process, with O-1(2) playing a significant role in facilitating the initial degradation rate. Factors such as initial pH values, siderite dosage, and PDS concentration were discussed, and the comprehensive degradation process was proposed based on LC-MS results. Additionally, the recyclability of siderite at a pH of 3 was demonstrated, highlighting the potential for using the siderite/PDS system for the degradation of sulfonamide pollutants.