Fe/Cu Bimetallic Particles for TCAL Dechlorination: From Parameter Effects to Reusable Catalysis with Mechanistic Insights

Iron/copper (Fe/Cu) bimetallic particles have demonstrated high activity for the dechlorination of trichloroacetaldehyde (TCAL). To enhance the dechlorination efficacy, a systematic evaluation of key operational parameters—such as chelator concentration, bimetal dosage, copper loading, and initial pH—is essential. The Fe/Cu bimetallic composites were synthesized and applied under optimized conditions (25 g/L Fe/Cu, EDTA/Cu molar ratio of 1:10, 1% Cu loading, initial pH 8). The materials were characterized before and after reaction using SEM-EDS, XRD, and XPS. Reaction intermediates were analyzed by gas chromatography with a micro electron capture detector (GC-μECD) to propose a degradation pathway. Under optimal conditions, a high TCAL removal rate of 98.18% and a dechlorination efficiency of 38.70% were achieved within 48 hours. Material characterization confirmed an iron-core structure with surface-deposited copper, which facilitated synergistic galvanic corrosion and improved surface reactivity. The degradation was attributed to hydrogen radicals (H•), the reducing power of Fe⁰ and Fe²⁺, and the adsorption by iron oxides (Fe₂O₃ and FeOOH). The Fe/Cu catalyst exhibited excellent recyclability over five cycles, and the degradation kinetics followed a pseudo-first-order model.