The permanganate(Mn(VII))oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds.Nonetheless,only a few studies ha...The permanganate(Mn(VII))oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds.Nonetheless,only a few studies have been conducted to explore the role of the heavy metals(especially the redox-active ones)during the Mn(VII)oxidation process.In this study,taking Pb(II)as an example,its influence on the Mn(VII)decontamination performance has been extensively investigated.It was found that,with the presence of Pb(II),Mn(VII)could degrade diclofenac(DCF),2,4-dichlorophenol,and aniline more effectively than without.For instance,over a wide pH range of 4.5–8.0,the dosing of 10μmol/L Pb(II)accelerated the DCF removal rate from 0.006–0.25 min–1 to 0.05–0.46 min–1 with a promotion factor of 1.9–9.4.Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII)could react with Pb(II)to produce Mn(IV)and Pb(IV)at pH 6.0–8.0,further experiments revealed that Pb(II)did not exert its enhancing effect through promoting the generation of MnO_(2),as the reactivity of MnO_(2)was poor under the employed pH range.At pH below 5.0,it was interesting to find that,a negligible amount of MnO_(2)was formed in the Mn(VII)/Pb(II)system in the absence of contaminants,while once MnO_(2)was generated in the presence of contaminants,it could catalyze the Pb(II)oxidation to Pb(IV)by Mn(VII).Collectively,by highlighting the conversion process of Pb(II)to Pb(IV)by either Mn(VII)or MnO_(2),the reactive Pb(III)intermediates were proposed to account for the Pb(II)enhancement effect.展开更多
基金This work was supported by the National Key Research and Development Program of China(No.2019YFC1805202)the National Natural Science Foundation of China(Grant Nos.22076143 and 22025601)+1 种基金the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF18021)the Shanghai Science and Technology Development Funds(No.20QB1404800).
文摘The permanganate(Mn(VII))oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds.Nonetheless,only a few studies have been conducted to explore the role of the heavy metals(especially the redox-active ones)during the Mn(VII)oxidation process.In this study,taking Pb(II)as an example,its influence on the Mn(VII)decontamination performance has been extensively investigated.It was found that,with the presence of Pb(II),Mn(VII)could degrade diclofenac(DCF),2,4-dichlorophenol,and aniline more effectively than without.For instance,over a wide pH range of 4.5–8.0,the dosing of 10μmol/L Pb(II)accelerated the DCF removal rate from 0.006–0.25 min–1 to 0.05–0.46 min–1 with a promotion factor of 1.9–9.4.Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII)could react with Pb(II)to produce Mn(IV)and Pb(IV)at pH 6.0–8.0,further experiments revealed that Pb(II)did not exert its enhancing effect through promoting the generation of MnO_(2),as the reactivity of MnO_(2)was poor under the employed pH range.At pH below 5.0,it was interesting to find that,a negligible amount of MnO_(2)was formed in the Mn(VII)/Pb(II)system in the absence of contaminants,while once MnO_(2)was generated in the presence of contaminants,it could catalyze the Pb(II)oxidation to Pb(IV)by Mn(VII).Collectively,by highlighting the conversion process of Pb(II)to Pb(IV)by either Mn(VII)or MnO_(2),the reactive Pb(III)intermediates were proposed to account for the Pb(II)enhancement effect.
