Application of calcined iowaite in arsenic removal from aqueous solution
Application of calcined iowaite in arsenic removal from aqueous solution
复制标题
煅烧碘等待石在水溶液除砷中的应用
DOI：
10.1016/j.clay.2016.04.002
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发表时间：
2016-06-01
影响因子：
5.6
通讯作者：
Ren, Tianlin
中科院分区：
文献类型：
--
作者：
Cao, Yaowu;Guo, Qinghai;Ren, Tianlin
与阴离子粘土的其他家族成员不同，Iowaite是一种镁铁基层状双氢氧化物，很少用于从天然或受污染的水中去除不受欢迎的成分。在这项研究中，考虑到阴离子粘土由于其相对较弱的层间结合而表现出很大的吸收阴离子污染物的能力，并且含铁矿物对砷酸盐和亚砷酸盐都具有很高的亲和力，因此使用硫铝石及其焙烧产品来处理添加砷的溶液。首次在300-1000℃的较宽温度范围内研究了合成水滑石的热分解过程和结构记忆效应，并在此基础上最终选择了450℃下得到的焙烧产物用于溶液脱砷实验。实验结果表明，原生毒砂中铁的含量显著影响其对亚砷酸盐的吸附行为，而焙烧过程削弱了铁含量对亚砷酸盐吸附的影响。与近年来常用的溶液除砷吸附剂以及本研究合成的纯水铝石相比，焙烧后的水铝石具有较高的砷吸收能力。对比实验表明，煅烧产物中的镁铁酸盐对提高焙烧后的钾锰矿的砷吸收能力没有贡献。因此，在其结构恢复过程中，由于层间砷氧阴离子的高度可利用性，焙烧水铝石在脱砷方面表现出更好的性能。砷氧阴离子不需要扩散到层间以取代原始的氯离子，就像它们对原始的Iowaite所做的那样。(C)2016爱思唯尔B.V.保留所有权利。
Unlike the other family members of anion clay, iowaite, a Mg-Fe based layered double hydroxide, was seldom used in removing undesirable constituents from natural or contaminated waters. In this study, iowaite as well as its calcination product were employed to treat arsenic-spiked solutions, taking into account that anion clays exhibited great capacity to incorporate anionic pollutants as a result of their relatively weak interlayer bonding, and Fe-bearing minerals had high affinity to both arsenate and arsenite. The thermal decomposition process and structural memory effect of synthetic iowaite were investigated over a wide temperature range of 300-1000 degrees C for the first time, based on which the calcination product obtained at 450 degrees C was finally selected to be used in solution dearsenication experiments. The experimental results showed that the content of Fe in pristine iowaite significantly affected its arsenite sorption behavior, whereas the calcination process weakened the effect of Fe content on arsenite uptake. The calcined iowaite was generally characterized with higher arsenic uptake capacity as compared to some other sorbents commonly used for arsenic removal from solution in recent years as well as the pristine iowaite synthesized in this study. A contrast experiment suggested that magnoferrite in the calcination products of iowaite made no contribution to the enhanced arsenic uptake capacity of calcined iowaite. Hence, calcined iowaite performed better in arsenic removal because of the high availability of arsenic oxyanions to the interlayer regions during its structural restoration. The arsenic oxyanions did not need to diffuse into the interlayers to replace the original chloride ions as they did for pristine iowaite. (C) 2016 Elsevier B.V. All rights reserved.