Experimental study of zero-valent iron induced nitrobenzene reduction in groundwater: The effects of pH, iron dosage, oxygen and common dissolved anions
Experimental study of zero-valent iron induced nitrobenzene reduction in groundwater: The effects of pH, iron dosage, oxygen and common dissolved anions
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DOI：
10.1016/j.cej.2012.01.030
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发表时间：
2012-03-01
影响因子：
15.1
通讯作者：
Yang, Bo
中科院分区：
文献类型：
--
作者：
Yin, Weizhao;Wu, Jinhua;Yang, Bo
地下水中的硝基苯（NB）由于其持久性和高毒性，已对健康构成重大风险。在本研究中，通过批量实验评估了初始pH值、铁投加量、氧气以及常见的溶解阴离子（包括Cl⁻、SO₄²⁻、NO₃⁻、HCO₃⁻、PO₄³⁻）和腐殖酸对零价铁（ZVI）还原硝基苯的影响。硝基苯的去除率随初始溶液pH值的降低而增加，在初始pH值为7.0时，去除效率达到88.7%。当铁投加量为0.5 g/L时，还原过程符合准零级动力学模型，相应的速率常数k(0)为1.76 mg/(L·h)。但当铁投加量在1.0 g/L至5.0 g/L之间时，其更符合准一级动力学，相应的速率常数k(1)在0.16 h⁻¹至0.76 h⁻¹之间。氧气会抑制硝基苯的还原，因为它会与零价铁争夺电子并生成铁的氧化物。与厌氧系统相比，在空气 - 水体系中观察到硝基苯去除率降低了17.1%。在有Cl⁻、SO₄²⁻和NO₃⁻存在的情况下，硝基苯的去除率有所提高，而当碳酸氢盐浓度超过50 mg/L时，它会成为一种抑制剂。PO₄³⁻和腐殖酸会显著抑制硝基苯的还原，因为它们可在铁表面形成内圈络合物。当它们的浓度分别达到8 mg/L和18 mg/L时，反应甚至会停止。（C）2012 Elsevier B.V.保留所有权利。
Nitrobenzene (NB) in groundwater has posed significant health risks because of its persistence and high toxicity. In this study, batch experiments were performed to evaluate the effects of initial pH, iron dosage, oxygen and common dissolved anions including Cl. SO42-, NO3-, HCO3-, PO43- and humic acid on the NB reduction by zero-valent iron (ZVI). The NB removal increased with the decrease of initial solution pH and a removal efficiency of 88.7% was obtained at an initial pH value of 7.0. The reduction process followed the pseudo-zero-order kinetic model when the iron dosage was 0.5 g L-1 and the corresponding rate constant k(0) was 1.76 mg L-1 h(-1). But it showed a better fit with the pseudo first order kinetics when iron dosage ranged from 1.0 g L-1 to 5.0 g L-1 with the corresponding rate constant k(1) between 0.16 h(-1) and 0.76 h(-1). Oxygen inhibited NB reduction due to its competing for electrons from ZVI and the generation of iron oxides. In comparison to the anaerobic system, a 17.1% decrease of NB removal was observed in the air-water system. Improvement of NB removal was observed in the present of Cl-, SO42- and NO3-, while bicarbonate would be an inhibitor if its concentration exceeds 50 mg L-1. The NB reduction was significantly inhibited by PO43- and humic acid since they could form inner-sphere complexes on iron surface. The reaction even ceased as their concentrations reached 8 and 18 mg L-1, respectively. (C) 2012 Elsevier B.V. All rights reserved.