Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
J Chromatogr A. 2009 Dec 11;1216(50):8697-704. doi: 10.1016/j.chroma.2009.01.043. Epub 2009 Jan 21.
In this work the activity of three carbohydrates (sucrose, glucose and fructose) in highly concentrated aqueous solutions was studied along with its effect on the adsorption behaviour of the investigated compounds. Activities of individual sugars in aqueous solutions of single solute as well as in binary mixtures were quantified on the basis of solubility properties. Solid-liquid equilibria of sugars were correlated with the NRTL (nonrandom, two liquid) model of activity coefficient formulation. Activities of individual sugars were incorporated into the single component adsorption isotherm model, which reproduced accurately the course of the adsorption equilibria of sugars in aqueous solutions obtained experimentally in previous work using an ion-exchange resin. Activities of sugars determined in binary solute systems along with the single component isotherms were used to predict competitive adsorption equilibria. To calculate adsorbed phase concentrations of individual sugars in binary mixtures the adsorbed solution theory was adopted. The isotherm shapes calculated were compared to the data of competitive adsorption from the former study and found to be able to describe these experimental results.
在这项工作中，研究了三种碳水化合物（蔗糖、葡萄糖和果糖）在高浓度水溶液中的活性及其对所研究化合物吸附行为的影响。基于溶解度性质，定量了单溶质水溶液和二元混合物中各糖的活性。采用非随机两液体（NRTL）活度系数模型对糖的固液平衡进行了关联。各糖的活度被纳入单组分吸附等温线模型，该模型准确地再现了先前使用离子交换树脂在实验中获得的糖在水溶液中吸附平衡的过程。在二元溶质体系中测定的糖的活度以及单组分等温线被用于预测竞争吸附平衡。为了计算二元混合物中各糖在吸附相中浓度，采用了吸附溶液理论。计算得到的等温线形状与之前研究中的竞争吸附数据进行了比较，结果表明能够描述这些实验结果。
