Treatment of malachite green in the wastewater of a shrimp farming activity using a H2O2/UV-LED system

Abstract

The free-radical- based advanced oxidation method is a method that can oxidize organic substances into simple molecules such as CO₂ and H₂O due to the formation of free radicals with strong oxidizing power. In this study, we investigated the decomposition of Malachile green (MG) compound in the wastewater of a shrimp farming activity by using H₂O₂/UV-LED system. The study showed that MG decomposition efficiency reached approximately 90% after 60 minutes of the UV irradiation in the presence of H₂O₂ with concentrations of 12 g.L^-1 and 24 g.L^-1. It led to the decomposition process of MG into benzophenone derivatives, and smaller and colorless molecules. Fluctuations in chemical and physical parameters related to wastewater quality during the decomposition process of MG compound were also investigated. The results showed that the oxidation of MG by H₂O₂ under UV irradiation reduced the concentration of total dissolved substances in the wastewater, while increasing its dissolved oxygen content by 2-4 times. The sutdy also showed that H₂O₂ promoted the decomposition of MG faster and more completely. The results revealed the role of advanced oxidation process in the valorization of MG by UV and H₂O₂.