Persson P, Nordin J, Rosenqvist J, Lövgren L, Öhman LO, Sjöberg S
Department of Inorganic Chemistry, Umeå University, Umeå, S-901 87, Sweden
J Colloid Interface Sci. 1998 Oct 1;206(1):252-266. doi: 10.1006/jcis.1998.5668.
This work is concerned with the adsorption of o-phthalate (1,2-benzenedicarboxylate) at the water-metal (hydr)oxide interface. Previously published infrared spectroscopic, potentiometric, and adsorption data characterizing the boehmite (gamma-AlOOH) system are compared with new data collected for o-phthalate adsorption on aged gamma-Al2O3 and goethite (alpha-FeOOH). The study focuses on identifying bonding mechanisms, stoichiometries, and stabilities of the formed complexes, and comparing these among the three systems. Furthermore, the effects of ionic strength and composition of the ionic medium are investigated. The infrared spectroscopic data provided direct, molecular-level evidence for the existence of two dominating surface complexes on all three solids. One was shown to be a deprotonated outer-sphere species and the other was an inner-sphere surface complex. The inner-sphere complexes on the three solids were structurally related, and they were tentatively assigned to a mononuclear, chelating structure involving both carboxylate groups. The outer-sphere complexes were shown to increase in relative importance at high pH and low ionic strengths, while low pH and high ionic strengths favored the inner-sphere complexes. The information gained from the infrared spectroscopic investigations was used as qualitative input in the formulation of the surface complexation models. New models, based on the extended constant capacitance approach, were presented for the o-phthalate/aged gamma-Al2O3 and o-phthalate/goethite systems. Copyright 1998 Academic Press.
本研究工作关注邻苯二甲酸酯（1,2 - 苯二甲酸酯）在水 - 金属（氢）氧化物界面的吸附情况。将先前发表的用于表征勃姆石（γ - AlOOH）体系的红外光谱、电位滴定和吸附数据，与新收集的关于邻苯二甲酸酯在老化γ - Al₂O₃和针铁矿（α - FeOOH）上吸附的数据进行了比较。该研究着重于确定所形成配合物的键合机制、化学计量比和稳定性，并在这三种体系之间进行比较。此外，还研究了离子强度和离子介质组成的影响。红外光谱数据为所有三种固体上存在两种主要表面配合物提供了直接的分子水平证据。其中一种被证明是去质子化的外层配合物，另一种是内层表面配合物。三种固体上的内层配合物在结构上相关，并且初步认定为涉及两个羧基的单核螯合结构。外层配合物在高pH值和低离子强度下相对重要性增加，而低pH值和高离子强度则有利于内层配合物。从红外光谱研究中获得的信息被用作表面络合模型公式中的定性输入。基于扩展恒电容方法，提出了针对邻苯二甲酸酯/老化γ - Al₂O₃和邻苯二甲酸酯/针铁矿体系的新模型。版权所有1998年学术出版社。
