A study on rapid acid chrome black (MB 7) spectrophotometric determination of ClO_(2) and catalytic degradation of 2,6-dinitro-p-cresol (DNPC) by ClO_(2)

Experiments were conducted to investigate the degradation of 2,6-dinitro-p-cresol(DNPC)in the chlorine dioxide(ClO_(2))catalytic oxidation process.Pure aluminum oxide was used as the catalyst in this process.The degradation of DNPC by ClO_(2) using aluminum oxide as catalyst was systematically studied by varying the experimental parameters,such as pH values,catalyst dosage,the initial concentration of DNPC and ClO_(2),reaction time,etc.Under optimal condition(DNPC concentration 39 mg$L–1,ClO_(2) concentration 0.234 g$L–1,reaction time 15 min,catalyst dosage 4.7 g$L–1 and pH 4.32),almost complete degradation of DNPC can be achieved.The kinetic studies revealed that the ClO_(2) catalytic oxidation degradation of DNPC followed pseudo-first-order kinetics with respect to both ClO_(2) and DNPC concentration.The repetitive use of the catalyst was investigated along sequential feed-batch trials.The catalyst performed efficiently afterfive runs.In addition,a simple and convenient method for the determination of ClO_(2) in water was developed by using acid chrome black 7(MB 7)spectrophotometry in this paper.