Liu A, Gonzalez RD
Chemical Engineering Department, Tulane University, New Orleans, Louisiana, 70118
J Colloid Interface Sci. 1999 Oct 1;218(1):225-232. doi: 10.1006/jcis.1999.6419.
Metal adsorption/desorption in a system consisting of humic acid, metal ions, and clay minerals is described. Montmorillonite and purified humic acid were selected as a prototype materials for this study. At a constant ionic strength, the amount of humic acid adsorbed on montmorillonite decreases when pH is increased. A slight increase in humic acid adsorption on montmorillonite is observed when there are bivalent metals present in the system. The metal adsorption on montmorillonite does not correlate to the amount of humic acid adsorbed on montmorillonite. Montmorillonite with preadsorbed humic acid does not show a significant change in the capacity of adsorbed metal ions. An increase in the ionic strength at a pH of 6.5 results in an increase in the adsorption of lead on montmotillonite in the presence of humic acid, while at a lower pH, the increase in ionic strength results in a decrease in metal adsorption. The bridging of bivalent metal ions between montmorillonite and humic acid is proposed as the dominant adsorption mechanism. Copyright 1999 Academic Press.
本文描述了由腐殖酸、金属离子和粘土矿物组成的体系中的金属吸附/解吸情况。本研究选用蒙脱石和纯化腐殖酸作为原型材料。在恒定离子强度下，随着pH值升高，蒙脱石上吸附的腐殖酸量减少。当体系中存在二价金属时，观察到蒙脱石对腐殖酸的吸附略有增加。蒙脱石对金属的吸附与蒙脱石上吸附的腐殖酸量无关。预先吸附了腐殖酸的蒙脱石在吸附金属离子的能力上没有显著变化。在pH值为6.5时，离子强度的增加导致在腐殖酸存在下铅在蒙脱石上的吸附增加，而在较低pH值下，离子强度的增加导致金属吸附减少。二价金属离子在蒙脱石和腐殖酸之间的桥联作用被认为是主要的吸附机制。版权所有1999年学术出版社。
