Degradation of organic pollutants by photoelectro-peroxone/ZVI process: Synergistic, kinetic and feasibility studies

Abstract

In this study a novel hybrid process was employed for the degradation of Metanil Yellow (MY). The operational parameters of photoelectro-peroxone/zero valent iron (PEP/ZVI) process were studied and the complete decoloration was found at pH = 3.0, 100 mg/L ZVI, 33.2 mg/L ozone, 300 mA applied current and 25 min reaction time. The combination of UV, ozone, electrogenerated H2O2 and ZVI showed high synergistic effect for MY degradation. ZVI showed high reusability in PEP/ZVI process. Among anions, nitrite ion demonstrated high inhibitory effect while chloride ions had no significant effect on MY degradation. Scavenging tests depicted that hydroxyl radical and singlet oxygen were the main agents of MY degradation. PEP/ZVI process was tested for several emerging pollutants (benzotriazole, 4-chlorophenol, carmoisine and tetracycline); the results presented the effectiveness of the process for the degradation of pollutants in a way that complete degradation occurred at only 30 min. Moreover, the performance of PEP/ZVI was examined for the treatment of two actual wastewaters. PEP/ZVI demonstrated an excellent function in terms of the removal of organic compounds to achieve discharging standards.