TY - JOUR
T1 - Effects of chloride ions on bleaching of azo dyes by Co2+/oxone regent
T2 - Kinetic analysis
AU - Wang, Zhaohui
AU - Yuan, Ruixia
AU - Guo, Yaoguang
AU - Xu, Lei
AU - Liu, Jianshe
PY - 2011/6/15
Y1 - 2011/6/15
N2 - Orange II (Org II), one of the most common used azo dyes, was taken as a model to investigate the effects of chloride ion on dye decoloration in cobalt/peroxymonosulfate (Co/PMS) system. A significant decrease in the rate of Org II decoloration was observed upon addition of Cl- (0.05-10mM), but further addition of Cl- (>50mM) apparently accelerated dyes degradation. This dual effect of chloride on dyes bleaching was also observed as other halide ions (e.g. Br-, I-) or other azo dyes were present in Co/PMS system. In the Co-free PMS solutions, the observed first-order rate constant always exponentially increased with the chloride content. The reactive chlorine species generated from chloride oxidation by PMS should be responsible for this non-radical mechanism for dye decoloration, however, these rapid decoloration of Org II as chloride ion was present, did not readily lead to much mineralization. Therefore, this finding may have significant technical implications for utilizing Co/PMS regent to detoxify chloride-rich azo dyes wastewater.
AB - Orange II (Org II), one of the most common used azo dyes, was taken as a model to investigate the effects of chloride ion on dye decoloration in cobalt/peroxymonosulfate (Co/PMS) system. A significant decrease in the rate of Org II decoloration was observed upon addition of Cl- (0.05-10mM), but further addition of Cl- (>50mM) apparently accelerated dyes degradation. This dual effect of chloride on dyes bleaching was also observed as other halide ions (e.g. Br-, I-) or other azo dyes were present in Co/PMS system. In the Co-free PMS solutions, the observed first-order rate constant always exponentially increased with the chloride content. The reactive chlorine species generated from chloride oxidation by PMS should be responsible for this non-radical mechanism for dye decoloration, however, these rapid decoloration of Org II as chloride ion was present, did not readily lead to much mineralization. Therefore, this finding may have significant technical implications for utilizing Co/PMS regent to detoxify chloride-rich azo dyes wastewater.
KW - Azo dyes
KW - Chloride
KW - Cobalt-mediated activation
KW - Decoloration
KW - Peroxymonosulfate
UR - https://www.scopus.com/pages/publications/79956105214
U2 - 10.1016/j.jhazmat.2011.04.016
DO - 10.1016/j.jhazmat.2011.04.016
M3 - 文章
C2 - 21524849
AN - SCOPUS:79956105214
SN - 0304-3894
VL - 190
SP - 1083
EP - 1087
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
IS - 1-3
ER -