共存硝酸盐对不同污染负荷下 mZVI 去除 TCE 的影响：动力学、电子效率和机制。
Effects of co-existing nitrate on TCE removal by mZVI under different pollution load scenarios: Kinetics, electron efficiency and mechanisms.
机构信息
Key Lab of Marine Environmental Science and Ecology, Ministry of Education, Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Key Lab of Marine Environmental Science and Ecology, Ministry of Education, Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
出版信息
Sci Total Environ. 2020 May 10;716:137111. doi: 10.1016/j.scitotenv.2020.137111. Epub 2020 Feb 4.
Microscale zero-valent iron in situ reaction zone (mZVI-IRZ) has proved to be effective and efficient for the removal of chlorinated aliphatic hydrocarbons (CAHs) from groundwater. However, nitrate (NO), which is ubiquitous in groundwater, affects the mZVI-based attenuation of CAHs in a complicated manner. Both the reaction rate constant (k) and electron efficiency (EE) of mZVI must be considered to comprehensively reflect the effects of NO on the short and long-term remediation performances of mZVI. Therefore, the influence of NO on trichloroethylene (TCE) removal under high-pollution-load (iron limited) and low-pollution-load (iron excess) conditions was investigated. Low concentrations of NO (10 and 50 mg N L) were found to enhance the TCE removal rate and efficiency, whereas high concentrations of NO (100 mg N L) inhibited the reaction. Although TCE removal was increased at low concentrations of NO, the EE of mZVI was dramatically decreased in the presence of NO at all concentration levels. Therefore, both the short-term TCE removal characteristics and the EE of mZVI should be considered when evaluating the long-term remediation effectiveness of mZVI-IRZ technology. The effects of NO on the TCE removal trends under high- and low-pollution-load scenarios were similar, but had different magnitudes. NO affected the TCE removal mainly by promoting mZVI corrosion, competing for electrons and affecting passivation product evolution. Our results provide guidance for the practical application of mZVI-IRZ technology.
微区零价铁原位反应区（mZVI-IRZ）已被证明是去除地下水中氯化脂肪烃（CAHs）的有效且高效的方法。然而，硝酸盐（NO）在地下水中普遍存在，以复杂的方式影响基于 mZVI 的 CAHs 的衰减。必须考虑反应速率常数（k）和电子效率（EE），以全面反映 NO 对 mZVI 的短期和长期修复性能的影响。因此，研究了在高污染负荷（铁有限）和低污染负荷（铁过量）条件下 NO 对三氯乙烯（TCE）去除的影响。发现低浓度的 NO（10 和 50 mg N L）会提高 TCE 的去除速率和效率，而高浓度的 NO（100 mg N L）会抑制反应。尽管在低浓度的 NO 存在下 TCE 的去除率有所提高，但在所有浓度水平下，mZVI 的 EE 都会显著降低。因此，在评估 mZVI-IRZ 技术的长期修复效果时，应同时考虑短期 TCE 去除特性和 mZVI 的 EE。NO 对高低污染负荷情况下 TCE 去除趋势的影响相似，但影响程度不同。NO 主要通过促进 mZVI 腐蚀、争夺电子和影响钝化产物演化来影响 TCE 的去除。我们的研究结果为 mZVI-IRZ 技术的实际应用提供了指导。
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