Investigating the efficiency of microscale zero valent iron-based in situ reactive zone (mZVI-IRZ) for TCE removal in fresh and saline groundwater.
Investigating the efficiency of microscale zero valent iron-based in situ reactive zone (mZVI-IRZ) for TCE removal in fresh and saline groundwater.
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DOI：
10.1016/j.scitotenv.2018.01.115
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
Jia Xin;Fenglin Tang;J. Yan;Chenghong La;Xilai Zheng;W. Liu
中科院分区：
文献类型：
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作者：
Jia Xin;Fenglin Tang;J. Yan;Chenghong La;Xilai Zheng;W. Liu
本研究在三种介质（Milli-Q水、淡水地下水和含盐地下水）中进行了长期柱实验，以评估不同现场条件下微尺度零价铁基原位反应区（mZVI-IRZ）的三氯乙烯（TCE）去除性能、电子效率（EE）和渗透率损失。通过将含有 TCE 的进水以 4mLh−1 的流速添加到充满混合 mZVI 颗粒和硅砂的柱中持续 6 个月，模拟了原位污染羽流修复的潜在场景。结果表明，在 6 个月的 100 个孔隙体积 (PV) 过程中，mZVI 在含盐地下水中显示出最低的 TCE 突破率 (0.0026 PV−1) 和最高的 TCE 去除能力 (43.72 mg)，但 EE 值最差 (25-40%)。矿物表征（SEM、XRD）、离子浓度分析和地球化学模拟证实，在三个柱内发现了不同的主要固体沉淀物（磁铁矿、菱铁矿、白云石/磁铁矿）。含有地下水的柱经历了最大的孔隙度损失，在 100 个 PV 过程中大约损失了 30.23mL。这项研究表明，为了改进 mZVI-IRZ 的设计，应考虑 EE 和水力传导率进行预测评估。
In this study, long-term column experiments were conducted in three media (Milli-Q water, fresh groundwater and saline groundwater) to evaluate the trichloroethylene (TCE) removal performance, electron efficiency (EE), and permeability loss of a microscale zero valent iron-based in situ reactive zone (mZVI-IRZ) under different field conditions. A potential scenario of in situ contamination plume remediation was simulated by adding a TCE-containing influent to columns filled with mixed mZVI particles and silica sand at a flow rate of 4 mL h−1for 6 months. Results showed that, over the course of 100 pore volumes (PV) for 6 months, mZVI displayed the lowest TCE breakthrough rate (0.0026 PV−1) and highest TCE removal capacity (43.72 mg) but the poorest EE value (25–40%) in saline groundwater. Mineral characterization (SEM, XRD), ion concentration analysis, and geochemical modeling corroborated that different dominant solid precipitates (magnetite, siderite, dolomite/magnetite) were identified inside the three columns. The column containing saline groundwater experienced the greatest porosity loss, approximately 30.23 mL over the course of 100 PVs. This study illustrates that, to improve designs of mZVI-IRZs, EE as well as hydraulic conductivity should be taken into consideration for predictive evaluations.