Guangzhou University (GU), Key Laboratory of Waters Safety & Protection in the Pearl River Delta, Ministry of Education, 510006 Guangzhou, China.
Chemosphere. 2011 Feb;82(6):866-71. doi: 10.1016/j.chemosphere.2010.10.089. Epub 2010 Nov 20.
The sorption behaviour of the severely toxic heavy metal thallium (Tl) as a monovalent cation onto three representative materials (goethite, pyrolusite and a natural sediment sampled from a field site) was examined as a function of pH in the absence and presence of two natural humic acids (HAs), using 204Tl(I) as a radiotracer. In order to obtain a basic understanding of trends in the pH dependence of Tl(I) sorption with and without HA, sorption of HAs and humate complexation of Tl(I) as a function of pH were investigated as well. In spite of the low complexation between Tl(I) and HAs, the presence of HAs results in obvious alterations of Tl(I) sorption onto pyrolusite and sediment. An influence on Tl(I) sorption onto goethite was not observed. Predictions of Kd (distribution coefficient) for Tl(I) on goethite in the presence of HAs, based on a linear additive model, agree well with the experimental data, while a notable disagreement occurs for the pyrolusite and sediment systems. Accordingly, it is suggested that HAs and goethite may act as a non-interacting sorbent mixture under the given conditions, but more complex interactions may take place between the HAs and the mineral phases of pyrolusite or sediment.
作为一价阳离子，将剧毒重金属铊（Tl）的吸附行为研究了三种代表性物质（针铁矿、软锰矿和从野外地点采集的天然沉积物）在不存在和存在两种天然腐殖酸（HA）时的 pH 值的函数关系，使用 204Tl（I）作为放射性示踪剂。为了基本了解在有和没有 HA 的情况下，Tl（I）吸附随 pH 值的变化趋势，还研究了 HA 的吸附和腐殖酸配合物对 Tl（I）的 pH 值依赖性。尽管 Tl（I）与 HA 之间的络合作用很低，但 HA 的存在会导致 Tl（I）在软锰矿和沉积物上的吸附明显改变。对 Tl（I）在针铁矿上的吸附没有影响。基于线性加和模型，预测在存在 HA 的情况下，Tl（I）在针铁矿上的 Kd（分配系数）与实验数据吻合良好，而在软锰矿和沉积物系统中则存在明显差异。因此，建议在给定条件下，HA 和针铁矿可能作为非相互作用的吸附剂混合物起作用，但 HA 与软锰矿或沉积物的矿物相之间可能发生更复杂的相互作用。
