A holistic approach to treating industrial Effluents: Photo-electro-assisted Fenton-like strategy for effective degradation and detoxification

The electro-assisted Fenton-like (EAF-like) and photoelectro-assisted Fenton-like (PEAF-like) processes were applied to real dye factory wastewater to evaluate pollutant degradation and toxicity reduction. A Box-Behnken design optimized the process for maximum total organic carbon (TOC) removal and color degradation while minimizing specific energy consumption (SEC). ANOVA results confirmed model reliability, with R² values of 99.18 % (TOC), 99.31 % (color), and 99.99 % (SEC) for EAF-like, and 99.80 % (TOC), 99.82 % (color), and 99.98 % (SEC) for PEAF-like. The optimal EAF-like conditions (4.7 g/L H₂O₂, 7 min, 9.2 V) achieved 32 % TOC removal, 90 % color removal, and an SEC of 2.86 kWh/kg TOC, whereas the optimized PEAF-like conditions (4.7 g/L H₂O₂, 6 min, 6.4 V, 545 mJ/cm² light intensity) resulted in 97 % TOC removal, 91 % color removal, and a significantly lower SEC of 0.599 kWh/kg TOC. Acute toxicity assessment using Daphnia magna showed that untreated wastewater had a 94 % immobilization rate, indicating severe toxicity. EAF-like treatment reduced toxicity to 88–28 %, while PEAF-like further decreased immobilization to 23–4 % under optimal conditions. The superior pollutant removal, energy efficiency, and toxicity reduction of PEAF-like highlight its potential as a sustainable solution for industrial wastewater treatment, demonstrating the significance of process optimization for large-scale applications. These findings suggest that the PEAF-like process is a highly efficient and energy-saving alternative for treating complex industrial wastewater, contributing to environmental sustainability and reducing ecological risks.