Bisulfite triggers fast oxidation of organic pollutants by colloidal MnO 2

• Published in: Journal of hazardous materials Vol. 363; p. 412
• Main Authors: Sun, Bo, Xiao, Zhongjin, Dong, Hongyu, Ma, Shangchen, Wei, Guangfeng, Cao, Tongcheng, Guan, Xiaohong
• Format: Journal Article
• Language: English
• Published: Netherlands 05.02.2019
• Subjects: Manganese dioxide; Bisulfite; Advanced oxidation; Mn(III)(aq); Electrophilic attack
• ISSN: 1873-3336

Colloidal MnO is the most reactive phase of Mn(IV) while HSO is a common reductant in water treatment. This study shows that the presence of HSO resulted in significant increase in the decomposition rate of organic contaminants by colloidal MnO . The degradation rate of contaminants in the MnO /HSO process dropped with elevating pH and a proper MnO /HSO - molar ratio was critical for efficient decomposition of contaminants. The time-resolved spectroscopy of manganese species, the influence of pyrophosphate on UV absorbance spectra, and the relative rate constants of contaminants oxidation in MnO /HSO process suggested that the synergetic effect of HSO and colloidal MnO arose from the generation of Mn(III) , which could oxidize contaminants rapidly. The presence of pyrophosphate, ethylenediaminetetraacetic acid, and humic acid depressed the degradation of contaminants in MnO /HSO process by complexing with Mn(III) , buffering the solution or competing with contaminants for Mn(III) , and/or inhibiting the consumption of bisulfite. However, Ca and Mg accelerated the oxidation of contaminants in MnO /HSO - process by enhancing the reduction of MnO by HSO -. The good negative correlation of the O/N or H Mulliken charges of organic contaminants with their removal in MnO /HSO process suggested that organic contaminants were oxidized by Mn(III) via electrophilic attack.