| 无机离子与胡敏酸对零价铁去除水中Pb（Ⅱ）、Hg（Ⅱ）的影响 |
| 摘要点击 1829 全文点击 1124 投稿时间：2014-01-17 修订日期：2014-03-26 |
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| 中文关键词 零价铁 铅离子 汞离子 无机离子 胡敏酸 |
| 英文关键词 zero-valent iron lead ion mercury ion inorganic ions humic acid |
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| 中文摘要 |
| 研究了Ca2+、 Cl-和胡敏酸（HA）对零价铁（ZVI）去除水中Pb（Ⅱ）、 Hg（Ⅱ）的影响及其动力学特征，应用X-射线衍射分析（XRD）初步探讨了ZVI对Pb（Ⅱ）、 Hg（Ⅱ）的去除机制. 结果表明，ZVI主要通过吸附-共沉淀作用去除水中的Pb（Ⅱ），氧化还原作用去除Hg（Ⅱ）. 随着Ca2+浓度的增加，Hg（Ⅱ）和Pb（Ⅱ）的去除率分别呈逐渐升高和轻微下降的趋势；增加Cl-浓度有利于Hg（Ⅱ）的去除，但Pb（Ⅱ）去除率增加不明显；Pb（Ⅱ）、 Hg（Ⅱ）去除率随HA浓度的增加分别呈缓慢升高和缓慢下降的趋势. 当Cl-、 Ca2+和HA共存时，Pb（Ⅱ）、 Hg（Ⅱ）的去除率分别达到99.71%和97.95%. 在Cl-、 Ca2+、 HA单独存在和共存时，ZVI去除Pb（Ⅱ）、 Hg（Ⅱ）的过程均符合准一级反应动力学特征；Pb（Ⅱ）的去除速率常数以5 mg·L-1 HA单独存在时最大（0.0240 min-1），而Hg（Ⅱ）以0.80 mmol·L-1 Ca2+单独存在时最大（0.0169 min-1）. |
| 英文摘要 |
| The effects of Ca2+, Cl- and humic acid (HA) on the removal rates of Pb(Ⅱ) and Hg(Ⅱ) in water by zero-valent (ZVI) and the kinetic characteristics were studied, and the removal mechanism of Pb(Ⅱ) and Hg(Ⅱ) by ZVI were preliminarily investigated using X-ray diffraction (XRD). The results indicated that the removal mechanism of Pb(Ⅱ) might mainly be attributed to the adsorption and co-precipitation of ZVI, while that of Hg(Ⅱ) might mainly be attributed to the oxidation-reduction of ZVI. With the increase of Ca2+ concentration, the removal rates of Hg(Ⅱ) and Pb(Ⅱ) showed the trends of gradual increase and slight decrease, respectively. The Hg(Ⅱ) removal increased with increasing Cl- concentration, whereas no obvious increase in Pb(Ⅱ) removal was observed. The removal rates of Hg(Ⅱ) and Pb(Ⅱ) showed the trends of slow increase and slow decrease with increasing HA concentration, respectively. When Ca2+, Cl- and HA coexisted, the removal rates of Hg(Ⅱ) and Pb(Ⅱ) reached 99.71% and 97.95%, respectively. The removal processes of Pb(Ⅱ) and Hg(Ⅱ) could be described by pseudo first-order reaction kinetic equations when Ca2+, Cl- and HA existed alone and in combination. The removal rate constant of Pb(Ⅱ) was the maximum (0.0240 min-1) when 5 mg·L-1 HA existed alone, whereas that of Hg(Ⅱ) was the maximum (0.0169 min-1) when 0.80 mmol·L-1 Ca2+ existed alone. |
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