Physicochemical study of novel organoclays as heavy metal ion adsorbents for environmental remediation.
Physicochemical study of novel organoclays as heavy metal ion adsorbents for environmental remediation.
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DOI：
10.1016/j.jcis.2007.07.078
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发表时间：
2007-12
影响因子：
9.9
通讯作者：
P. Stathi;Kiriaki Litina;D. Gournis;T. Giannopoulos;Y. Deligiannakis
中科院分区：
文献类型：
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作者：
P. Stathi;Kiriaki Litina;D. Gournis;T. Giannopoulos;Y. Deligiannakis
以SWy-2蒙脱石为基质，通过在蒙脱石层间嵌入不同螯合官能团（NH 2、COOH、SH和CS2）的铵基有机衍生物，制备了4种有机改性蒙脱石。有机分子如（a）六亚甲基二胺、（B）2-（二甲氨基）乙烯基乙二胺、（c）5-氨基戊酸和（d）六亚甲基二胺-二硫代氨基甲酸酯用于粘土改性以研究螯合官能团对水溶液中重金属离子结合的影响。采用X射线粉末衍射（XRD）、红外光谱（FTIR）和核磁共振（NMR）等手段对有机粘土进行了表征。实验数据表明，有机分子以平行于粘土片层的长向嵌入层间空间。他们的吸附性能进行了评价，从水溶液中去除重金属，铅，镉和锌，作为pH值的函数。当与未改性的SWY-2蒙脱石相比，改性粘土表现出显着的改善，吸附选择性以及金属负载量。吸附数据的表面络合模型拟合表明，插层分子作为特定的结合位点的粘土。这些有助于额外的吸附能力，这是添加剂的可变电荷的边缘网站的粘土在竞争中的永久电荷网站。
Four organic-modified clays based on a SWy-2 montmorillonite were prepared by embedding ammonium organic derivatives with different chelating functionalities (NH2, COOH, SH or CS2) in the interlayer space of montmorillonite. Organic molecules such as (a) hexamethylenediamine, (b) 2-(dimethylamino)ethenethiol, (c) 5-aminovaleric acid and (d) hexamethylenediamine-dithiocarbamate were used for the clay modification in order to study the effect of the chelating functionality on heavy metal ions binding from aqueous solutions. The organoclays were characterized by powder X-ray diffraction (XRD), infrared (FTIR) and NMR spectroscopies. The experimental data showed that the organic molecules are intercalated into the interlamelar space with the long dimension parallel to the clay sheets. Their sorbing properties were evaluated for the removal of heavy metals, Pb, Cd and Zn, from aqueous solutions as a function of the pH. When compared with the unmodified SWy-2 montmorillonite, the modified clays show significant improvement in terms of sorbing selectivity as well as of metal loading capacity. The fit to adsorption data by a Surface Complexation Model shows that the intercalated molecules act as specific binding sites in the clay. These contribute additional sorption capacity which is additive to the variable charge edge-sites of the clay in competition with the permanent charge sites.