Treatment of azo dye production wastewaters using Photo-Fenton-like advanced oxidation processes: Optimization by response surface methodology

Treatability of synthetic azo dye production wastewaters from Acid Blue 193 and Reactive Black 39 production and real Reactive Black 39 production effluent via Photo-Fenton-like process was investigated. Response surface methodology was employed to assess individual and interactive effects of critical process parameters (Fe3+, H2O2 concentrations; initial chemical oxygen demand (COD) and reaction time) on treatment performance in terms of color, COD and total organic carbon (TOC) removal efficiencies. Optimized reaction conditions for synthetic AB 193 production wastewater were established as Fe3+ = 1.5 mM; H2O2 = 35 mM for CODs ≤ 200 mg/L and a reaction time of 45 min. Under these conditions, 98% color, 78% COD and 59% TOC removals were experimentally obtained and fitted the model predictions well. The same model also described the treatment of synthetic Reactive Black 39 production wastewater satisfactorily. Experimentally achieved removals were considerably lower than model predictions for real Reactive Black 39 production effluent due to its high chloride content.