Performance evaluation and proposed mechanistic insights into Cu‐based heterogeneous Fenton catalysts for the treatment of food dye manufacturing wastewater

Abstract

Organic dyes discarded from food dye manufacturing industries are persistent pollutants because of their complicated molecular structures, low biodegradability, and resistance to conventional biological treatment. This study systematically evaluated Cu‐based heterogeneous Fenton catalysts (Cu‐SiO ₂ , Cu‐Al ₂ O ₃ , and Cu‐Fe bimetallic) using genuine food‐color manufacturing wastewater and compared their performance with conventional homogeneous Fenton treatment. Experiments were performed at laboratory scale under optimized operating conditions to compare pollutant removal, partial mineralization, biodegradability enhancement, sludge formation, and treatment performance. The Cu‐Fe bimetallic catalyst showed better performance with ~70% COD removal, 47% TOC reduction, 99.84% color removal, and 88.54% UV ₂₅₄ reduction within 60 min of reaction. Moreover, the BOD/COD ratio increased from 0.019 to 0.17, while sludge production was significantly lower than that of the homogeneous Fenton method. Thus, the novelty of the present work lies in the systematic performance and practical evaluation of Cu‐Fe bimetallic heterogeneous Fenton treatment using real, highly concentrated food‐color manufacturing wastewater, including assessment of oxidation efficiency, biodegradability, sludge generation, and treatment cost. However, the H ₂ O ₂ dosage of 84 g/L used under the optimized conditions is relatively high and represents an important limitation for industrial application, highlighting the need for further optimization of oxidant dosage to reduce chemical consumption and improve process feasibility.