Degradation of Azo Dyes Wastewater Using Chlorine Dioxide and A Ternary Catalyst NiO-CuOx-La2O3/Al2O3

Abstract

A ternary catalyst (NiO-CuO_x-La₂O₃/Al₂O₃) for chlorine dioxide (ClO₂) catalytic oxidation of azo dyes was prepared by the dipping-calcination method with activated alumina as carrier. With the simulated wastewater containing Reactive brilliant red KD-8B (RBR) as the treating object, the catalytic activity of the catalyst and the degradation features were explored. The results showed that this reaction follows apparent pseudo-first-order reaction kinetics and the reaction rate constant increased by 195 % than that of reaction without the catalyst, so the ternary catalyst can significantly reduce the time of degradation reaction and the ClO₂ dosage. The order of the degradation activity of various groups in the Reactive brilliant red KD-8B molecular structure was: azo bond > non-aromatic carbon-carbon double bond > carbon-nitrogen bond in triazine > aromatic carbon-carbon bond. It also proved that in the catalyst the active components combined with the carrier by strong chemical bonds and the catalyst was stable. So it provided a highly efficient catalyst for chlorine dioxide catalytic oxidation technology applied in treating azo dyes wastewater.