Electrolyte reactivity on electrode surfaces for active species formation and Reactive Red X-3B degradation in electrochemical treatment of dyeing wastewater

초록

The pivotal role of electrolytes such as Na2SO4 and NaCl in electrochemical treatment of dyeing wastewater was investigated by comparing recalcitrant Reactive Red X-3B (RRX-3B) degradation rates, active species formation and intermediates generation in a double-chamber cell. It was found that similar reactive oxygen species (ROS) formed in the anodic chamber are •OH and 1O2, in the cathodic chamber is •O2− with different electrolytes, while this is not the case for ROS contribution, RRX-3B degradation kinetic and intermediates. NaCl favored the generation of 1O2, faster decolorization (−N=N− cleavage), and organic intermediates degradation in the anodic chamber. A comparatively faster hydrogenation reduction of −N=N− and higher COD removal with fewer organic categories in Na2SO4 cathodic chamber outperformed those in NaCl cathodic chamber. The RRX-3B degradation pathways were proposed in both chambers based on GC-MS investigations and Fukui function calculations. Atoms Cl, S and N in RRX-3B molecule removals were in the order of R−S > R−N > R−Cl. © 2025

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