Role of reactive oxygen species and effect of solution matrix in trichloroethylene degradation from aqueous solution by zeolite-supported nano iron as percarbonate activator

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• 作者：Muhammad Danish ; Xiaogang Gu ; Shuguang Lu ; Minhui Xu…
• 刊名：Research on Chemical Intermediates
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：42
• 期：9
• 页码：6959-6973
• 全文大小：1,389 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Catalysis
  Physical Chemistry
  Inorganic Chemistry
  
• 出版者：Springer Netherlands
• ISSN：1568-5675
• 卷排序：42

文摘

The role of reactive oxygen species (ROSs) and effect of solution matrix have been investigated for the degradation of trichloroethylene (TCE). Zeolite-supported nano iron (Z-nZVI) was synthesized as an activator to catalyze sodium percarbonate (SPC) with or without hydroxylamine, i.e. as reducing agent (RA). The probe tests confirmed the generation of OH· and O₂−· in the Z-nZVI activated SPC system in absence of the RA, while the presence of RA significantly increased the generation of OH· and O₂−· radicals. Scavenger tests demonstrated that OH· was the main ROS responsible for TCE degradation, whereas O₂−· also participated in TCE degradation. From the solution matrix perspective, the experimental results confirmed significant scavenging effects of Cl− (1.0, 10.0, and 100 mmol L−1) and HCO₃− (1.0 and 10.0 mmol L−1), whereas the scavenging effects were fairly impeded at 100 mmol L−1 concentration of HCO₃−. On the other hand, a considerable decline in scavenging effect was observed in the presence of RA in tested Cl− and HCO₃− concentration ranges. In addition, negligible scavenging effects of NO₃− and SO₄2− anions were found in all tested concentrations. The effect of initial solution pH on catalytic activity indicated a significant increase in the TCE degradation in the presence of RA even at higher pH value of 9. The results indicated that the Z-nZVI activated SPC system in presence of RA can effectively degrade chlorinated organic solvents, but it is important to consider the intensive existence of anions in groundwater.KeywordsTrichloroethylene (TCE)Solution matrixReactive oxygen species (ROSs)Zeolite supported nano iron particles (Z-nZVI)Groundwater remediation