Role of Cysteine in Enhanced Degradation of Trichloroethane under Ferrous Percarbonate System

Abstract The removal of toxic contaminants such as trichloroethane (TCA) from groundwater had a huge impact due to associated health hazards. Advanced oxidation technology has an outstanding potential to remove these toxins. However, the redox cycling of Fe(II)/Fe(III) is mostly a barrier for the efficient removal of these contaminants. In this study, we extracted two in one nature of cysteine (CYS) to enhance TCA degradation in Fe(II)/sodium percarbonate (SPC) system. The chelating and reducing capability of CYS, concentration impact of Fe(II), SPC, and pH role were all thoroughly investigated. The existence of hydroxyl (OH●) and superoxide (O2–●) radicals were confirmed through quencher tests. Furthermore, the electron paramagnetic resonance (EPR) spectra evaluated the enhancement of OH● radicals in the Fe(II)/CYS/SPC system due to the electron transfer capability of CYS. The Fe(II)/CYS/SPC showed excellent recyclability and stability characteristics up to 68% TCA degradation in the fourth round. The degradation products and dechlorination analysis confirmed the existence of non-toxic final products. Similarly, the system demonstrated admirable performance in a real groundwater system, bolstering its real-time industrial applications. Conclusively, Fe(II)/CYS/SPC can be a viable and effective method for degrading chlorinated organic hydrocarbons in groundwater.