The electrochemical degradation of sulfachloropyridazine (SCP) was investigated using an electro-Fenton (EF) process assisted by chalcopyrite as a heterogeneous catalyst and in situ source of Fe2⁺ and Cu2⁺ ions, replacing the soluble iron salts commonly employed in conventional EF systems. Experiments were conducted in a batch reactor equipped with a platinum anode and a carbon-felt cathode under continuous air injection. The degradation mechanism involved the generation of hydroxyl radicals \(HO^{ \cdot }\) both at the anode surface through water oxidation and within the bulk solution via Fenton reactions between electrogenerated H₂O₂ and dissolved metal ions. These highly reactive species promoted the oxidation and degradation of SCP molecules. The influence of key operating parameters, including chalcopyrite dosage (0.5–1.5 g/L), current density (2.83–5.66 mA/cm2), and initial pH (1.5–4.5), was evaluated using a full factorial design (FFD). Eleven experimental runs were performed, and SCP removal efficiency was selected as the response variable. The experimental results showed good agreement with the values predicted by the statistical model. Kinetic analysis revealed that SCP degradation followed pseudo-first-order kinetics, with an apparent rate constant of 0.138 min⁻1. Under the optimal conditions of pH 4.5, current density of 2.83 mA/cm2, and chalcopyrite concentration of 1.5 g/ L, complete degradation of 0.2 mM SCP was achieved within 25 min. In addition, 92% total organic carbon (TOC) removal was obtained after 480 min of electrolysis, indicating extensive mineralization of the organic matter. The residual TOC detected in the treated solution was mainly associated with the formation of low-molecular-weight aliphatic carboxylic acids identified by HPLC analysis. Overall, the proposed EF/chalcopyrite system demonstrates high potential for the efficient treatment of wastewater containing refractory organic contaminants.
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