Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
Water Res. 2017 Nov 15;125:191-200. doi: 10.1016/j.watres.2017.08.044. Epub 2017 Aug 23.
A 12 days laboratory study on potential desorption of Lanthanum (La) from a commercial La modified clay (Phoslock) was conducted using lake water from 17 Danish lakes with alkalinities between 0.02 and 3.7 meq L and varying concentrations of DOC and humic acids (HA's). A similar study was conducted in artificial lake water with alkalinities from 0 to 2.5 meq Lin order to exclude interference from dissolved HA's. To test if La in solution (FLa) was associated with fine particles, the water samples were filtered sequentially through three filter sizes (1.2 μm, 0.45 μm and 0.2 μm), and finally, ultracentrifugation was used in an attempt to separate colloidal La from dissolved La. The study showed that higher FLa (up to 2.5 mg L or 14% of the total La in the Phoslock) concentrations were found in soft water lakes compared to hard water lakes, probably due to dispersion of the clay at low alkalinities. In addition, this study showed that HA's seem to increase the FLa concentrations in soft water lakes, most likely through complexation of La retained in the Phoslock matrix. In summary, we conclude that elevated La concentrations in lake water after a Phoslock treatment should only be expected in soft water lakes rich in DOC and HA's.
进行了一项为期 12 天的实验室研究，以评估镧（La）从商业镧改性粘土（Phoslock）上解吸的潜力。研究使用了来自丹麦 17 个湖泊的湖水，这些湖泊的碱度在 0.02 到 3.7 meq/L 之间，DOC 和腐殖酸（HA）的浓度也各不相同。在人工湖水中进行了类似的研究，其碱度从 0 到 2.5 meq/L，以排除溶解态 HA 的干扰。为了测试溶液中的 La（FLa）是否与细颗粒有关，将水样依次通过三种不同孔径的过滤器（1.2 μm、0.45 μm 和 0.2 μm）进行过滤，最后采用超速离心法试图将胶体 La 与溶解态 La 分离。研究表明，与硬水湖泊相比，软水中湖泊的 FLa（高达 2.5 mg/L 或 Phoslock 中总 La 的 14%）浓度更高，这可能是由于低碱度下粘土的分散。此外，本研究表明，HA 似乎会增加软水中湖泊的 FLa 浓度，这很可能是由于 Phoslock 基质中保留的 La 与 HA 发生了络合。总之，我们得出结论，Phoslock 处理后，在富含 DOC 和 HA 的软水中湖泊中，预计会出现 La 浓度升高的情况。
