Study on the treatment of 2- sec-butyl-4,6-dinitrophenol (DNBP) wastewater by ClO 2 in the presence of aluminum oxide as catalyst

Abstract

The chlorine dioxide (ClO 2) oxidative degradation of 2- sec-butyl-4,6-dinitrophenol (DNBP) in aqueous solution was studied in detail using Al 2O 3 as a heterogeneous catalyst. The operating parameters such as the ClO 2 concentration, catalyst dosage, initial DNBP concentration, reaction time and pH were evaluated. Compared with the conventional ClO 2 oxidation process without the catalyst, the ClO 2 catalytic oxidation system could significantly enhance the degradation efficiency. Under the optimal condition (DNBP concentration 39 mg L −1, ClO 2 concentration 0.355 g L −1, reaction time 60 min, catalyst dosage 10.7 g L −1 and pH 4.66), degradation efficiency approached 99.1%. The catalyst was used at least 8 cycles without any appreciable loss of activity. The kinetic studies revealed that the ClO 2 catalytic oxidation degradation of DNBP followed pseudo-first-order kinetics with respect to DNBP concentration. The ClO 2 catalytic oxidation process was found to be very effective in the decolorization and COD Cr reduction of real wastewater from DNBP manufacturing. Thus, this study showed potential application of ClO 2 catalytic oxidation process in degradation of organic contaminants and industrial effluents.