Center for the Development of Nanoscience and Nanotechnology, CEDENNA, 9170124, Santiago, Chile; Facultad de Química y Biología, Universidad de Santiago de Chile, Av. B. O'Higgins, 3363, Santiago, Chile.
Center for the Development of Nanoscience and Nanotechnology, CEDENNA, 9170124, Santiago, Chile.
J Hazard Mater. 2015 Dec 15;299:675-84. doi: 10.1016/j.jhazmat.2015.08.007. Epub 2015 Aug 6.
Modification of surface charge and changes in the isoelectric point (IEP) of synthetic imogolite were studied for various cations in the background electrolyte (K(+), NH4(+), Mg(2+), and Ca(2+)). From the electrophoretic mobility data, it was established that the K(+) (KCl) concentration does not affect the IEP of imogolite; therefore, KCl is a suitable background electrolyte. In terms of the magnitude of changes in the IEP and surface charge, the cations may be ranked in the following order: Mg(2+)≈Ca(2+)>>NH4(+)>>K(+). Four different kinetic models were used to evaluate the influence of Mg(2+), Ca(2+), NH4(+), and K(+) on the adsorption of Cd and Cu on synthetic imogolite. When adsorption occurs in the presence of cations with the exception of K(+), the kinetics of the process is well described by the pseudo-first order model. On the other hand, when adsorption is conducted in the presence of K(+), the adsorption kinetics is well described by the pseudo-second order, Elovich, and Weber-Morris models. From the surface charge measurements, the affinity between imogolite and the cations and their effect on the adsorption of trace elements, namely Cu and Cd, were established.
研究了不同背景电解质（K(+)、NH4(+)、Mg(2+)和 Ca(2+)）中阳离子对合成埃洛石表面电荷和等电点（IEP）的修饰作用。从电泳迁移率数据可知，K(+)（KCl）浓度不影响埃洛石的 IEP；因此，KCl 是一种合适的背景电解质。从 IEP 和表面电荷变化的大小来看，阳离子的排序如下：Mg(2+)≈Ca(2+)>>NH4(+)>>K(+)。使用了四种不同的动力学模型来评估 Mg(2+)、Ca(2+)、NH4(+)和 K(+)对合成埃洛石吸附 Cd 和 Cu 的影响。当除 K(+)以外的阳离子存在时，吸附过程的动力学很好地用准一级模型描述。另一方面，当在 K(+)存在下进行吸附时，吸附动力学很好地用准二级、Elovich 和 Weber-Morris 模型描述。通过表面电荷测量，确定了埃洛石与阳离子之间的亲和力及其对痕量元素（即 Cu 和 Cd）吸附的影响。
