Cruz-Guzmán Marta, Celis Rafael, Hermosín M Carmen, Cornejo Juan
Instituto de Recursos Naturales y Agrobiología de Sevilla, CSIC, Avda Reina Mercedes 10, Apdo 1052, 41080 Sevilla, Spain.
Environ Sci Technol. 2004 Jan 1;38(1):180-6. doi: 10.1021/es030057w.
Three organic cations with a natural origin (L-carnitine, L-cystine dimethyl ester, and thiamine) were introduced at different loadings in the interlayer of a low-charge montmorillonite, and the performance of the modified clays as adsorbents of the herbicide simazine was investigated using batch adsorption-desorption experiments. The organic cations were selected on the basis of their natural origin and the presence of diverse functional groups in their structures, which was expected to influence simazine adsorption. Elemental analysis and spectroscopy results demonstrated the presence of the organic cations in the modified montmorillonites and their entrance in the clay mineral interlayers. Batch adsorption results showed that modification with thiamine (K(f) = 96-138), cystine dimethyl ester (K(f) = 400-753), and especially carnitine (K(f) > 10 000) enhanced the adsorption of simazine by montmorillonite (K(f) = 28-47). It appeared that the specific interlayer microenvironment provided by the functional groups of each organic cation was an important factor controlling the adsorption efficiency of the modified clays. For carnitine and cystine dimethyl ester, the increase in simazine adsorption was considerably greater than that observed after montmorillonite modification with "classical" alkylammonium cations, such as phenyltrimethylammonium or hexadecyltrimethylammonium. This illustrated how modification of smectitic clay minerals with natural organic cations containing appropriate functional groups can be a useful strategy to improve the performance of organoclays for the removal of specific organic pollutants from the environment.
将三种天然来源的有机阳离子（L-肉碱、L-胱氨酸二甲酯和硫胺素）以不同负载量引入低电荷蒙脱石的层间，并通过批量吸附-解吸实验研究了改性粘土作为除草剂西玛津吸附剂的性能。选择这些有机阳离子是基于它们的天然来源以及其结构中存在的不同官能团，预计这些官能团会影响西玛津的吸附。元素分析和光谱结果表明改性蒙脱石中存在有机阳离子，并且它们进入了粘土矿物层间。批量吸附结果表明，用硫胺素（K(f)=96-138）、胱氨酸二甲酯（K(f)=400-753），尤其是肉碱（K(f)>10000）改性可提高蒙脱石对西玛津的吸附（K(f)=28-47）。似乎每个有机阳离子的官能团提供的特定层间微环境是控制改性粘土吸附效率的重要因素。对于肉碱和胱氨酸二甲酯，西玛津吸附的增加明显大于用“经典”烷基铵阳离子（如苯基三甲基铵或十六烷基三甲基铵）改性蒙脱石后观察到的增加。这说明了用含有适当官能团的天然有机阳离子对蒙脱石粘土矿物进行改性如何能够成为一种有用的策略，以提高有机粘土从环境中去除特定有机污染物的性能。
