Treatment of Reactive Blue Dye-Contaminated Water via Activated Carbon Adsorption and Electrochemical Degradation

Reactive blue 19 (RB19) is a toxic anionic dye with an anthraquinone moiety, characterized by its intense color and resistance to degradation. In this article, a three-dimensional electrochemical system was constructed, using Ti/RuO2 as anode and steel plate as cathode, combining electrochemical degradation and activated carbon adsorption. RB19 was partially degraded on the surface of the Ti/RuO2 plate eventually. Simultaneously, the granular activated carbon was polarized under the influence of the electric field during the degradation process, the generation of hydroxyl radical in the system and enhancing the mass transfer capacity and current density was catalyzed. Under the optimal conditions, the three-dimensional system filled with granular activated carbon treated RB19 for 1 h with a removal rate far exceeding that of the two-dimensional system, reaching 82.9%, while its synergistic efficiency reached 39%. Furthermore, the removal rate remained 64.9% after 5 cycles. The results suggested that electrochemical oxidation and adsorption can synergistically treat RB19 in the system. Electrochemical tests verified that the mass transfer rate and current density of the three-dimensional system were significantly enhanced compared to the two-dimensional system. Specially, the mass transfer rate (k) of the three-dimensional system was improved by 10.7% compared to the two-dimensional system, reaching 0.031. Finally, hydroxyl radical was detected through electron paramagnetic resonance test, and the possible degradation pathway of dye was inferred by liquid chromatography-mass spectrometry detection of the intermediates. This method provides a more efficient, eco-friendly, and cost-effective approach for treating dye wastewater.