Enhanced degradation of trichloroethylene using bentonite-supported nanoscale Fe/Ni and humic acids

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• 作者：Shihe Wang ; Yitong Han ; Xi Cao ; Dan Zhao ; Dezhong Yang…
• 刊名：Environmental Chemistry Letters
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：14
• 期：2
• 页码：237-242
• 全文大小：722 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geochemistry
  Analytical Chemistry
  Biochemistry
  Monitoring, Environmental Analysis and Environmental Ecotoxicology
  Soil Science and Conservation
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1610-3661
• 卷排序：14

文摘

Nanoscale zero-valent iron, named nano-Fe0, is a reagent used to degrade trichloroethylene in groundwater. However, the efficiency of nano-Fe0 is moderate due to issues of dispersion and reactivity. As an alternative we synthesized bentonite-supported nanoscale Fe/Ni bimetals, named bentonite-Fe/Ni, to test the degradation of trichloroethylene in the presence of Suwannee River humic acids, as a representative of natural organic matter. 0.1 mmol/L trichloroethylene was reacted with 0.5 g/L of nano-Fe0, bentonite-Fe, Fe/Ni, and bentonite-Fe/Ni nanoparticles. Results show first that without humic acids the reaction rate constants k_obs were 0.0036/h for nano-Fe0, 0.0101/h for bentonite-Fe, 0.0984/h for Fe/Ni, and 0.181/h for bentonite-Fe/Ni. These findings show that bentonite-Fe/Ni is the most efficient reagent. Second, the addition of humic acids increased the rate constant from 0.178/h for 10 mg/L humic acids to 0.652/h for 40 mg/L humic acids, using the bentonite-Fe/Ni catalyst. This finding is explained by accelerated dechlorination by faster electron transfer induced by humic quinone moieties. Indeed, the use of 9, 10-anthraquinone-2, 6-disulfonate as a humic analogue gave similar results.KeywordsBentonite-supported nanoscale Fe/Ni bimetalsTrichloroethyleneDegradationNatural organic matterHumic acidElectron shuttle