Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008, USA.
J Colloid Interface Sci. 2009 Nov 15;339(2):302-9. doi: 10.1016/j.jcis.2009.07.053. Epub 2009 Jul 28.
Cadmium adsorption was measured as a function of ionic strength (0.001-0.1M NaNO(3)), and spanning a range of sorbate/sorbent ratios, on pure hydrous ferric oxide (HFO), kaolinite, and quartz and also on binary and ternary mixtures of the three solids. Diffuse- layer surface complexation models (DLMs) were parameterized to fit Cd sorption data for the pure kaolinite and quartz systems. Cd adsorption on kaolinite was modeled using a two-site DLM, with formation of a monodentate Cd complex on a variable charge site and Cd binding to a permanent exchange site; Cd adsorption on quartz was described using a one-site DLM with formation of a mondentate Cd complex on a variable charge site. These DLMs, together with the Dzombak and Morel DLM for HFO, were used to predict Cd adsorption on the binary and ternary mineral mixtures using a simple component additivity approach. In general, the predicted adsorption edges were in good agreement with measured data, with statistically similar goodness of fit compared to that obtained for the pure mineral systems. However, in some cases the model overpredicted Cd sorption, possibly indicating that interaction of the solids may prevent Cd from accessing all of the sorption sites.
镉吸附作为离子强度的函数（0.001-0.1M NaNO(3)）进行了测量，并跨越了一系列吸附剂/吸附剂比，在纯水合氧化铁（HFO）、高岭石和石英上，以及在三种固体的二元和三元混合物上进行了测量。扩散层表面络合模型（DLM）被参数化以拟合纯高岭石和石英体系的 Cd 吸附数据。高岭石上的 Cd 吸附采用双位点 DLM 进行建模，其中在可变电荷位点上形成单齿 Cd 络合物，Cd 结合到永久交换位点；石英上的 Cd 吸附采用单位点 DLM 进行描述，其中在可变电荷位点上形成单齿 Cd 络合物。这些 DLM 与 Dzombak 和 Morel 用于 HFO 的 DLM 一起，用于使用简单的组分加和方法预测二元和三元矿物混合物上的 Cd 吸附。一般来说，预测的吸附边缘与测量数据吻合良好，拟合优度与纯矿物体系相当。然而，在某些情况下，模型会过高地预测 Cd 吸附，这可能表明固体之间的相互作用可能会阻止 Cd 进入所有吸附位点。
