基于NaHSO_(3)活化KMnO_(4)原位生成三价锰的有机污染物降解

Degradation of organic pollutants by Mn( Ⅲ) in situ generated from bisulfite activated permanganate

为研究NaHSO_(3)活化KMnO_(4)过程中短时间内生成的非络合态三价锰对不同污染物的反应活性,结合停留光谱仪和动力学模型,分析三价锰氧化苯酚的表观二级速率常数,并通过相对速率法计算出三价锰氧化其余23种新兴污染物的表观二级速率常数,结果显示大部分常数介于1.14×10^(6)~4.38×10^(6)L/(mol􀅰s)。通过定量构效关系分析新兴污染物与三价锰的反应机理,并对NaHSO_(3)活化KMnO_(4)过程中降解不同结构新兴污染物的效能进行预测,结果显示酚类化合物氧化速率与其官能团氧原子电荷呈负相关关系,与Hammett常数呈负相关关系,与最高占据分子轨道呈正相关关系,表明三价锰是一种亲电氧化剂,倾向于氧化具有富电子官能团的有机污染物。本研究结果有助于推动NaHSO_(3)活化KMnO_(4)工艺在水处理领域中的应用。

The reactivity of Mn(Ⅲ)generated rapidly from the bisulfite activated permanganate process(PM/BS process)towards different pollutants was investigated.The apparent second-order rate constant of phenol oxidation by Mn(Ⅲ)was calculated by a kinetic model and the stopped-flow spectrophotometer.With the relative rate method,the value of k of other 23 kinds of pollutants were calculated and most of them fall in the range of 1.14×10^(6)-4.38×10^(6)L/(mol􀅰s).Quantitative structure-activity relationships were conducted to analyze the reaction mechanism of pollutant with Mn(Ⅲ)and predict the removal of pollutant by the PM/BS process.The negative correlation of phenol oxidation rate with the charge on oxygen atom,the negative slope of the linear relationship of Hammett′s constant with second-order rate constant(kapp),the positive correlation of kapp with the value of highest occupied molecular orbital,suggested the electrophilic reactions of pollutant oxidation by Mn(Ⅲ).The results of this study promoted the progress of the PM/BS process toward the full-scale application in water treatment.