Performance and kinetic evaluation of pyrite-activated heterogeneous Fenton-like oxidation for COD removal from real small-scale textile effluent

Abstract

This study evaluated the performance of pyrite-activated heterogeneous Fenton-like oxidation for the treatment of real effluent generated from a local batik/textile industry. The influence of key operational parameters, including initial pH, hydrogen peroxide concentration, and pyrite dosage, was systematically investigated to determine the optimal conditions for COD removal. The results showed that acidic conditions significantly enhanced oxidation performance, with maximum COD removal achieved at pH 3. The optimal operating parameters were identified as 10 g L⁻¹ H₂O₂, 1 g L⁻¹ pyrite dosage, and a reaction time of 6 h at room temperature, resulting in approximately 90% COD removal. Kinetic evaluation indicated that the degradation process followed a pseudo-first-order model, as evidenced by a high correlation coefficient (R²), with an apparent rate constant of 0.362 min⁻¹. The findings suggest that hydrogen peroxide was present in excess, allowing the reaction rate to be primarily governed by COD concentration. Overall, this study demonstrates the potential applicability of natural pyrite as an effective and low-cost catalyst for treating real textile effluent. Further investigation into catalyst stability and reusability is recommended to enhance the economic feasibility of the process.