Sustainable Enzyme-Assisted Coagulation for Decolorization and Detoxification of Acid Dye

This study proposes an enzyme-assisted coagulation (EAC) system as a novel, nature-inspired, energy-free approach for the treatment of acid dyes in textile wastewater. The EAC system combines enzymatic oxidation with natural polymer-based coagulation, proceeding under mild conditions without the need for external energy input. In this study, horseradish peroxidase (HRP) catalyzed the oxidative breakdown of the dye, while chitosan served as a representative biopolymer coagulant, facilitating the aggregation of degradation products through electrostatic and hydrogen-bonding interactions. Analytical techniques, including UV–vis spectroscopy, FTIR, HPLC, and GC-MS, confirmed the effective degradation and coagulation of dye byproducts. Furthermore, acute toxicity assays using Daphnia magna demonstrated that the EAC system substantially reduced ecotoxicity compared with enzymatic or coagulation treatments alone. This flexible and sustainable platform is applicable to a wide range of acid dyes, offering a scalable, low-carbon alternative to conventional dye wastewater treatment methods.