Adsorption of zearalenone by organomodified natural zeolitic tuff
Adsorption of zearalenone by organomodified natural zeolitic tuff
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DOI：
10.1016/j.jcis.2007.02.033
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发表时间：
2007-07-01
影响因子：
9.9
通讯作者：
Clewett, Catherine F. M.
中科院分区：
文献类型：
--
作者：
Dakovic, Aleksandra;Matijasevic, Srdan;Clewett, Catherine F. M.
研究了用不同数量的十八烷基二甲基苄基铵 (ODMBA) 离子改性的天然沸石凝灰岩对玉米赤霉烯酮 (ZEN) 的吸附。起始原料的固态 H-1 NMR 分析结果表明，沸石凝灰岩富含矿物斜发沸石，证实了先前热稳定性研究的结果。制备了三种有机沸石（OZ-2、OZ-5 和 CZ-10），ODMBA 表面覆盖度分别为 20、50 和 100 mmol/100 g。通过测定 pH 3、7 和 9 下的吸附等温线，研究了三种有机沸石对 ZEN 的吸附机理。在 pH 3 时，有机沸石对 ZEN 的吸附最好由线性型等温线表示，而在 pH 7 和 9 时，有机沸石对 ZEN 的吸附遵循非线性（Langmuir）型等温线。不同pH值下沸石表面具有不同ODMBA水平的三种有机沸石的ZEN吸附等温线的不同形状表明吸附机制可能取决于ZEN在溶液中的形式。由于在 pH 3 时，ZEN 以中性形式存在于溶液中，因此 pH 3 时的线性等温线表明疏水相互作用可能是中性疏水 ZEN 吸附到有机沸石疏水表面上的原因。在 pH 7 时，酚盐阴离子存在于水溶液中，而在 pH 9 时，ZEN 几乎完全呈阴离子形式。三种有机沸石对 ZEN 吸附的非线性等温线表明，吸附似乎是吸附过程和分配的结果。 (C) 2007 Elsevier Inc. 保留所有权利。
Adsorption of zearalenone (ZEN) by natural zeolitic tuff, modified with different numbers of octadecyidimethylbenzylammonium (ODMBA) ions, was investigated. The results of solid-state H-1 NMR analysis of the starting material suggested that zeolitic tuff is rich in mineral clinop- tilolite, confirming the results of previous thermal stability study. Three organozeolites (OZ-2, OZ-5, and CZ-10) were prepared with ODMBA surface coverages of 20, 50, and 100 mmol/100 g. The mechanism of ZEN sorption by the three organozeolites was investigated through the determination of the adsorption isotherms at pH 3, 7, and 9. Adsorption of ZEN by organozeolites was best represented by a linear type of isotherm at pH 3, while at pH 7 and 9, adsorption of ZEN by organozeolites followed a nonlinear (Langmuir) type of isotherm. The different shape of the ZEN adsorption isotherms for the three organozeolites with different levels of ODMBA at the zeolitic surface at different pH values suggests that the adsorption mechanism may be dependent on the form of ZEN in solution. Since, at pH 3, ZEN exists in solution as the neutral form, the linear isotherms at pH 3 suggested that hydrophobic interactions are probably responsible for adsorption of neutral, hydrophobic ZEN onto the hydrophobic surface of the organozeolites. At pH 7, the phenolate anion is present in water solution, while at pH 9, ZEN is almost entirely in the anionic form. The nonlinear isotherms obtained for ZEN adsorption by the three organozeolites suggest that sorption appears to be the result of the adsorption process as well as partitioning. (C) 2007 Elsevier Inc. All rights reserved.