Wastewater treatment using waste cuprous oxide: A circular economy approach towards green and sustainable laboratory waste management

In this study, waste Cu₂O was used as a Fenton-like catalyst for treating laboratory wastewater using hydrogen peroxide (H₂O₂) as an oxidant. The catalytic efficiency of Cu₂O towards the decomposition of crystal violet, methylene blue, and safranin was evaluated. The catalyst was recycled and reused up to five catalytic cycles without significant loss of catalytic efficiency against these dyes. Wastewater from the biology laboratory containing these toxic dyes was successfully treated using the same catalyst with excellent efficiency. Post-treatment, copper was recovered as copper sulphate pentahydrate with a 96 % of copper recovery. Furthermore, the toxicity of untreated and treated water was studied against E. coli. Additionally, the survival of the aerial microbes in treated water was evaluated and compared with that of drinking water, and it was found to be almost the same.