Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands.
Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Regional Water Authority Brabantse Delta, P.O. Box 5520, 4801 DZ Breda, The Netherlands.
Water Res. 2014 May 1;54:78-88. doi: 10.1016/j.watres.2014.01.059. Epub 2014 Feb 5.
The lanthanum (La) modified bentonite Phoslock(®) has been proposed as dephosphatisation technique aiming at removing Filterable Reactive Phosphorus (FRP) from the water and blocking the release of FRP from the sediment. In the modified clay La is expected the active ingredient. We conducted controlled laboratory experiments to measure the FRP removal by Phoslock(®) in the presence and absence of humic substances, as La complexation with humic substances might lower the effectiveness of La (Phoslock(®)) to bind FRP. The results of our study support the hypothesis that the presence of humic substances can interfere with the FRP removal by the La-modified bentonite. Both a short-term (1 d) and long-term (42 d) experiment were in agreement with predictions derived from chemical equilibrium modelling and showed lower FRP removal in presence of humic substances. This implies that in DOC-rich inland waters the applicability of exclusively Phoslock(®) as FRP binder should be met critically. In addition, we observed a strong increase of filterable La in presence of humic substances reaching in a week more than 270 μg La l(-1) that would infer a violation of the Dutch La standard for surface water, which is 10.1 μg La l(-1). Hence, humic substances are an important factor that should be given attention when considering chemical FRP inactivation as they might play a substantial role in lowering the efficacy of metal-based FRP-sorbents, which makes measurements of humic substances (DOC) as well as controlled experiments vital.
镧（La）改性膨润土 Phoslock(®)已被提议作为除磷技术，旨在去除水中的可过滤性反应磷（FRP）并阻止 FRP 从沉积物中释放。在改性粘土中，La 是预期的有效成分。我们进行了控制实验室实验，以测量 Phoslock(®)在存在和不存在腐殖质物质的情况下对 FRP 的去除效果，因为 La 与腐殖质物质的络合可能会降低 La（Phoslock(®)）结合 FRP 的有效性。我们研究的结果支持这样的假设，即腐殖质物质的存在会干扰 La 改性膨润土对 FRP 的去除。短期（1 天）和长期（42 天）实验均与化学平衡模型预测一致，表明在存在腐殖质物质的情况下 FRP 的去除率较低。这意味着在 DOC 丰富的内陆水域中，仅使用 Phoslock(®)作为 FRP 结合剂的适用性应受到严格限制。此外，我们观察到在存在腐殖质物质的情况下可过滤的 La 含量大幅增加，在一周内达到 270μg La l(-1)以上，这将违反荷兰地表水的 La 标准，即 10.1μg La l(-1)。因此，腐殖质物质是一个重要的因素，在考虑化学 FRP 失活时应引起重视，因为它们可能在降低基于金属的 FRP 吸附剂的效果方面发挥重要作用，这使得腐殖质物质（DOC）的测量以及控制实验变得至关重要。
