Degradation of Dichloromethane Containing Laboratory Wastewater Using Photoelectric Fenton Process

Abstract

Conducting laboratory experiments in educational institutions has been linked with the increased amount of chemical waste disposed in the environment. The excessive usage and disposal of Dichloromethane (DCM) has been attributed to financial and environmental concerns. This present study aimed to treat the DCM containing laboratory wastewater using Photoelectric Fenton (PEF) process. The PEF treatment was done at varying ultraviolet (UV) light intensity (3, 6 and 9 Watts), sacrificial anode (Al, Cu and TiO₂), and oxidizing agent (OA) loading ratio (1.13, 3.76, and 6.39 w/w) under 30^oC and 1 atm. Results have shown that the highest degradation (99.82%) of DCM was obtained at 9 Watts of UV light intensity, 3.76 w/w [H₂O₂]:[Fe²⁺] OA loading ratio, and with TiO₂ coated with IrO₂ and RuO₂ as the anode. It was detected that higher UV light intensity favors the degradation efficiency when using the TiO₂ coated with IrO₂ and RuO₂ anode. On the other hand, higher OA loading ratios proved to negatively affect the process as high concentrations of H₂O₂ become ineffectual for the degradation of organics. Finally, analysis of variance (ANOVA) showed the positive correlation between degradation efficiency and UVA light intensity.  This confirmed the applicability of the PEF process in degrading of recalcitrant pollutants in wastewater, thus showing potential for mitigating its environmental impact.