RECYCLED IRON SLUDGE FROMHOMOGENEOUS FENTON TREATMENT AS A LOW-COST CATALYST FOR WATER TREATMENT APPLICATIONS
The increasing application of Fenton-based advanced oxidation processes for treating high-strength industrial effluents, such as bioethanol wastewater, generates substantial amounts of iron sludge as a secondary byproduct. Although commonly regarded as waste, this iron-rich material offers potential for reuse as a catalytic precursor within a circular economy framework. This study investigates the physicochemical properties of iron sludge derivedfrom homogeneous Fenton treatment of bioethanol wastewater and evaluates its feasibility for catalytic reuse. Thesludge was characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), andScanning Electron Microscopy (SEM). FTIR analysis revealed Fe–O bonds, surface hydroxyl groups, and residual organic functionalities, indicating the presence of chemically active sites. XRD results confirmed γ-FeOOH(lepidocrocite) as the dominant phase, accompanied by partially crystalline iron-based structures associatedwithredox activity. SEM images showed irregular, aggregated particles with porous and rough surface morphologiesfavourable for heterogeneous catalytic reactions. To assess practical applicability, the recovered iron sludge wasreused in a Fenton-like process, achieving 84.72% COD removal, compared to 97.63% obtained using fresh catalyst in a conventional homogeneous Fenton system. These findings demonstrate that iron sludge generated fromFentontreatment can be effectively transformed into a low-cost, functional iron-based catalyst. The study providesimportant insights into the sustainable management of Fenton-derived waste, supports the development of waste- derived catalytic materials, and contributes to advancing environmentally responsible water treatment technologies.
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