CIESC Journal ›› 2013, Vol. 64 ›› Issue (9): 3373-3380.DOI: 10.3969/j.issn.0438-1157.2013.09.040

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Characteristics of removing Cr(Ⅵ)of Fe-Cu bimetal PRB coated by sodium alginate

ZHU Wenhui1,2, WANG Xingrun2, DONG Liangfei1, WANG Qi2, HE Jie2   

  1. 1. School of Environmental & Safety Engineering, Changzhou University, Changzhou 213164, Jiangsu, China;
    2. Chinese Research Academy of Environmental Sciences, Beijing 100012, China
  • Received:2013-01-05 Revised:2013-04-07 Online:2013-09-05 Published:2013-09-05
  • Supported by:

    supported by the High-tech Research and Development Program of China(2009AA063101-2).

海藻酸钠包覆型Fe-Cu双金属PRB填料的除Cr(Ⅵ)特性

朱文会1,2, 王兴润2, 董良飞1, 王琪2, 何洁2   

  1. 1. 常州大学环境与安全工程学院, 江苏 常州 213164;
    2. 中国环境科学研究院, 北京 100012
  • 通讯作者: 王兴润
  • 作者简介:朱文会(1988- ),男,硕士研究生。
  • 基金资助:

    国家高技术研究发展计划项目(2009AA063101-2)。

Abstract: The surface reaction between zero-valent iron and Cr(Ⅵ)makes the utilization rate of Fe0-permeable reactive barrier(PRB)very low.In order to resolve this problem,sodium alginate(SA)was used to coat cast iron(SAC)and copper-iron bimetallic particles(SAB),and they were tested in treating chromium-polluted groundwater.The results show that SAB is the best.Adsorption capacity of SA to Cr(Ⅵ)is small,chemisorptions of copper-iron bimetallic particles in SAB plays main role.As indicated by FEI and XPS,pore structures were created by cross-linking of SA with Ca2+,which not only provided a lot of attaching points for bimetallic particles,but also diffusion path for Cr(Ⅵ)to enter interior of copper-iron bimetallic particles.The results of XPS also indicate that variation of copper valence was used for transfer of electrons from reaction of Cr(Ⅵ)by Fe0 and the role of copper is as if a catalyst.Under neutral condition,the removal process of Cr(Ⅵ)by SAB follows the pseudo first-order kinetics.The rate constant k increase with increasing copper loading(for SAB)and copper-iron bimetal amount(for SAB2), and decrease with Cr(Ⅵ)concentration(for SAB2).The rate constant is higher and removal capacity greater for SAB than for cast iron powder.Using SAB as the PRB is feasible for remediation of chromium contaminated groundwater.

Key words: Cr(Ⅵ), groundwater, PRB, Fe0, sodium alginate, copper-iron bimetallic particles

摘要: Fe0与Cr(Ⅵ)发生表层反应使Fe0-渗透反应墙(PRB)利用率很低。针对Fe0利用率低问题,研究了海藻酸钠(SA)包覆型铁粉填料(SAC)和SA包覆型Fe-Cu双金属填料(SAB)对受污染地下水中Cr(Ⅵ)的去除影响;实验结果表明,SAB效果最好。SAB中双金属的化学吸附占主导作用,SA自身对Cr(Ⅵ)的吸附容量很小。SAB2(镀铜1%)的FEI电镜扫描及XPS能谱分析结果表明,SA与2价金属阳离子Ca2+交联形成孔隙结构,不仅为双金属的附着提供了大量的吸附点位,还可使Cr(Ⅵ)进入到内部与双金属反应;Cu在Fe0与Cr(Ⅵ)反应中起催化剂作用,通过自身化合态变化传递Fe0失去的电子。在中性条件下,对SAB进行动力学拟合,符合准一级化学反应动力学。且随着镀铜量的增加,SAB反应速率常数k逐渐增大;随着初始Cr(Ⅵ)浓度的增大,SAB2反应速率常数k逐渐下降;随着双金属投加量的增大,SAB2反应速率常数k线性递增。相比SAC和纯铁粉,SAB具有较大的去除能力和较高的反应速率,采用SAB治理Cr(Ⅵ)污染地下水是可行的。

关键词: Cr(Ⅵ), 地下水, 渗透反应墙, 零价铁, 海藻酸钠, Fe-Cu双金属

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