Simultaneous separation of iodide and cesium ions from dilute wastewater based on PPy/PTCF and NiHCF/PTCF electrodes using electrochemically switched ion exchange method
Simultaneous separation of iodide and cesium ions from dilute wastewater based on PPy/PTCF and NiHCF/PTCF electrodes using electrochemically switched ion exchange method
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基于PPy/PTCF和NiHCF/PTCF电极的电化学开关离子交换法同时分离稀废水中的碘离子和铯离子
DOI：
10.1016/j.seppur.2014.11.003
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发表时间：
2015-01-02
影响因子：
8.6
通讯作者：
Ma, Guozhang
中科院分区：
文献类型：
--
作者：
Liao, Senliang;Xue, Chunfeng;Ma, Guozhang
首次采用电化学开关离子交换（ESIX）方法，分别在两种多孔三维碳毡（PTCF）上制备了聚吡咯（PPy）和六氰合铁酸镍（NiHCF）膜，并将其用于放射性碘（I-）和铯（Cs+）离子的分离。结果表明，外加电位显著提高了吸附效率，较低的pH值有利于分离过程的进行。最大吸附量均在95.3mg/g以上。在pH值为1.89 ~ 936范围内，吸附率均在88%以上. I-和Cs+离子的最终解吸率分别约为87%和90%。这种分离建议进行两个主要步骤：一个ESIX步骤，其中PPy的电化学氧化和NiHCF的电化学还原迅速发生（快速步骤），和IX步骤，这是由膜和本体溶液之间的离子浓度梯度控制（缓慢步骤）。分离因子（α（I）（CI）= 90和α（cs）（Na）= 458.8）分别显示出对I-（PPI膜）和Cs+（NiHCF膜）离子的高选择性，而对Cl-和Na+离子的选择性则不同。5次连续的吸附-脱附实验表明，NiHCF/PTCF和PPy/PTCF电极可有效再生且稳定。该方法可望成为一种有前途的实际废水处理技术。(C)2014爱思唯尔有限公司版权所有。
Radioactive iodide (I-) and cesium (Cs+) ions were first simultaneously separated using electrochemically switched ion exchange (ESIX) method based on polypyrrole (PPy) and nickle hexacyanoferrate (NiHCF) films, which were chemically deposited on two porous three-dimensional carbon felts (PTCF), respectively. It was found that applied potential significantly facilitated the adsorption efficiency and the lower pH value was beneficial to the separation process. The maximum adsorption capacity of both ions approached above 95.3 mg/g. The adsorption ratios of I- ion kept above 88% at pH value ranged from 1.89 to 936. The ultimate I- and Cs+ ion desorption rates were proximately 87% and 90%, respectively. Such separation was suggested to proceed in two main steps: an ESIX step in which electrochemical oxidation of PPy and electrochemical reduction of NiHCF occurred rapidly (the fast step), and an IX step which was controlled by the gradients of ion concentrations between films and bulk solution (the slow step). The separation factors (alpha(I)(CI) = 90 and alpha(cs)(Na) = 458.8) showed high selectivity for I- (PPI film) and Cs+ (NiHCF film) ions over Cl- and Na+ ions, respectively. And five consecutive adsorption-desorption experiments indicated that the NiHCF/PTCF and PPy/PTCF electrodes can be effectively regenerated and are stable. It is expected that the developed method can be taken as a promising technology for actual wastewater treatment. (C) 2014 Elsevier B.V. All rights reserved.