Synergistic degradation of toxic azo dyes using Mn-CuO@Biochar: An efficient adsorptive and photocatalytic approach for wastewater treatment

• Breakthrough in Solar Photocatalysis : Mn co-doped CuO with Biochar achieves record-breaking degradation of organic pollutants . • Unlocking Efficient Degradation: H 2 O 2 addition boosts removal of harmful pollutants by up to 90% • Unveiling Degradation Pathways: In-depth investigation reveals crucial insights into toxic byproducts and mineralization routes. • Green Technology Advancement: Biochar-based photocatalyst showcases immense potential for sustainable wastewater treatment . • Toxicity Assessment: Comprehensive evaluation of treated water ensures safe discharge into the environment, ensuring a healthier ecosystem. Congo red (CR) and Eriochrome Black T (EBT) is a toxic azo dye with a complex structure which represents a serious Ecotoxicological hazards for aquatic bodies. This research investigates the synergistic effects of Corn plants biochar and manganese (Mn)-composited copper oxide (CuO) in the adsorptive and photocatalytic degradation of toxic anionic dyes i.e. CR and EBT. The acquired materials were characterized by FTIR, XRD, SEM-EDX, XPS, TEM, BET, ZP, and pHZc test. The experiment demonstrated that Mn-CuO@BC composite exhibited a remarkable adsorption of ∼ 98 % and ∼ 95 % and photocatalytic degradation of 92 % and 88 % for CR and EBT respectively. It was further found that coupling of the H 2 O 2 with Mn-CuO@BC enhances the photocatalytic efficiency of catalyst for CR and EBT i.e. upto ∼ 98 % and 96 % respectively possibly owing to the efficient ● OH radical. Adsorption kinetics followed a pseudo 2nd order model, indicating predominant chemisorption, and adsorption isotherms fit well with the Langmuir model. Further, toxicity degradation products of EBT were examined through ECOSAR indicated a reduced ecological impact. In general, this work highlight the dual functional advantages of the Mn-CuO@BC composite, providing an efficient and versatile approach for wastewater treatment involving complex dye pollutants.