Influence of Zn(II) on the Adsorption of Arsenate onto Ferrihydrite
Influence of Zn(II) on the Adsorption of Arsenate onto Ferrihydrite
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DOI：
10.1021/es300729m
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发表时间：
2012-12-18
影响因子：
11.4
通讯作者：
Hedlund, Jonas
中科院分区：
文献类型：
--
作者：
Carabante, Ivan;Grahn, Mattias;Hedlund, Jonas
在砷污染的土壤中添加氧化铁已被提议作为降低砷在土壤中的流动性的一种手段。砷和锌是土壤中常见的共存污染物。因此，锌的存在可能会影响砷在氧化铁上的吸附特性，从而影响其在土壤中的流动性。研究了Zn（II）对铁氧化物吸附砷酸根离子的影响。批吸附实验表明，锌（II）增加了砷酸盐的去除从溶液中的水铁矿在pH值为8。然而，ATR-FTIR光谱表明，没有吸附的砷酸盐在水铁矿膜上发生在pD 8在Zn（II）的存在下。沉淀的氢氧化锌碳酸盐，然后由砷酸adorption上的沉淀物被认为是一个合理的机制，解释的砷酸盐从溶液中的Zn（II）的存在下，在pH/pD 8的去除。先前提出的机制归因于增强的去除砷酸盐从溶液中的存在下，锌（II）的铁氧化物上的额外吸附不能被验证的实验条件下研究。结果还表明，在pH/pD 4，Zn（II）的存在下，在系统中没有显着影响的砷酸盐的吸附在水铁矿。
Addition of iron oxide to arsenic-contaminated soil has been proposed as a means of reducing the mobility of arsenic in the soil. Arsenic and zinc are common coexisting contaminants in soils. The presence of zinc therefore may affect the adsorption properties of arsenic on iron oxide, and may thus affect its mobility in the soil. The influence of Zn(II) on the adsorption of arsenate ions on iron oxide was studied. Batch adsorption experiments indicated that Zn(II) increased the arsenate removal from a solution by ferrihydrite at pH 8. However, ATR-FTIR spectroscopy showed that no adsorption of arsenate on a ferrihydrite film occurred at pD 8 in the presence of Zn(II). Precipitation of zinc hydroxide carbonate followed by arsenate adorption onto the precipitate was found to be a plausible mechanism explaining the arsenate removal from a solution in the presence of Zn(II) at pH/pD 8. The previously suggested mechanisms attributing the enhanced removal of arsenate from solution in the presence of Zn(II) to additional adsorption on iron oxides could not be verified under the experimental conditions studied. It was also shown that at pH/pD 4, the presence of Zn(II) in the system did not significantly affect the adsorption of arsenate on ferrihydrite.