It is well known that zero-valent iron(ZVI)could catalyze the oxidation of various oxidants to realize the rapid oxidation removal of pollutants.However,in this study,we found that the addition of different oxidants c...It is well known that zero-valent iron(ZVI)could catalyze the oxidation of various oxidants to realize the rapid oxidation removal of pollutants.However,in this study,we found that the addition of different oxidants could regulate the redox function of ZVI system.In three different co-treatment systems,the effects of different oxidizers(peroxymonosulfate(PMS),persulfate(PDS),hydrogen peroxide(H_(2)O_(2)))dosages on the ratios of oxidative degradation rate and reductive degradation rate of p-nitrophenol(PNP)were studied.The effect of the H+released from oxidizers and the generated reactive oxygen species(ROS)in ZVI/PMS,ZVI/PDS,ZVI/H_(2)O_(2)systems were detailed discussed.Especially,the contribution of generated ROS for reductive degradation of PNP was quantified in the ZVI/H_(2)O_(2)system.Based on the results of TOC removal,UV-vis absorption spectra,and intermediates concentration curves,it was found that the degradation of PNP changed from reduction to oxidation with the increase of oxidant proportion.When the molar ratio of ZVI to oxidizer equal to 100,PNP was mainly degraded by reduction accompanied by slight oxidation.Combined with the results of SEM-EDS and XPS,it was confirmed that the enhanced degradation of PNP under the addition of oxidant was mainly related to the generated ROS,the additional H+,and the corrosion products of ZVI.展开更多
基金financial support from Key R&D projects of the Sichuan Science and Technology Plan Project(No.19ZDYF0612)Guiding Plan for Transfer and Transformation of Scientific and Technological Achievements of Sichuan Science and technology plan project(No.20ZHSF0257)the National Natural Science Foundation of China(No.51878423)。
文摘It is well known that zero-valent iron(ZVI)could catalyze the oxidation of various oxidants to realize the rapid oxidation removal of pollutants.However,in this study,we found that the addition of different oxidants could regulate the redox function of ZVI system.In three different co-treatment systems,the effects of different oxidizers(peroxymonosulfate(PMS),persulfate(PDS),hydrogen peroxide(H_(2)O_(2)))dosages on the ratios of oxidative degradation rate and reductive degradation rate of p-nitrophenol(PNP)were studied.The effect of the H+released from oxidizers and the generated reactive oxygen species(ROS)in ZVI/PMS,ZVI/PDS,ZVI/H_(2)O_(2)systems were detailed discussed.Especially,the contribution of generated ROS for reductive degradation of PNP was quantified in the ZVI/H_(2)O_(2)system.Based on the results of TOC removal,UV-vis absorption spectra,and intermediates concentration curves,it was found that the degradation of PNP changed from reduction to oxidation with the increase of oxidant proportion.When the molar ratio of ZVI to oxidizer equal to 100,PNP was mainly degraded by reduction accompanied by slight oxidation.Combined with the results of SEM-EDS and XPS,it was confirmed that the enhanced degradation of PNP under the addition of oxidant was mainly related to the generated ROS,the additional H+,and the corrosion products of ZVI.