Effects of chloride ions on bleaching of azo dyes by Co2+/oxone reagent: kinetic analysis.
Effects of chloride ions on bleaching of azo dyes by Co2+/oxone reagent: kinetic analysis.
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DOI：
10.1016/j.jhazmat.2011.04.016
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发表时间：
2011-06
影响因子：
13.6
通讯作者：
Zhao-hui Wang;Ruixia Yuan;Yaoguang Guo;Lei Xu;Jianshe Liu
中科院分区：
文献类型：
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作者：
Zhao-hui Wang;Ruixia Yuan;Yaoguang Guo;Lei Xu;Jianshe Liu
以偶氮染料橙黄II(Org II)为模型，研究了在钴/过一硫酸盐(Co/PMS)体系中氯离子对染料脱色的影响。加入氯离子−(0.0510 mM)可显著降低有机II染料的脱色率，但进一步加入氯离子−(>；50mM)可明显加速染料的降解。在Co/PMS体系中存在其他卤离子(如BR-−、I-−)或其他偶氮染料时，也观察到了氯对染料漂白的双重影响。在无钴的PMS溶液中，观察到的一级速率常数总是随氯化物含量呈指数增加。PMS氧化氯离子产生的活性氯物种应该是染料脱色的非自由基机理，然而，这些以氯离子形式存在的Org II快速脱色并不容易导致太多的矿化。因此，这一发现可能对利用Co/PMS试剂脱毒富氯偶氮染料废水具有重要的技术意义。
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−(0.05–10 mM), but further addition of Cl−(>50 mM) 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.