Department of Agricultural, Food and Environmental Sciences (D3A), Polytechnic University of Marche, Via Brecce Bianche 10, 60131, Ancona, Italy.
Department of Agricultural, Food and Environmental Sciences (DSA3), University of Perugia, Borgo XX Giugno, Perugia, Italy.
Environ Sci Pollut Res Int. 2020 May;27(15):18803-18809. doi: 10.1007/s11356-020-08469-x. Epub 2020 Mar 23.
A laboratory trial was performed to test the sequestration capacity of two minerals (bentonite and zeolite) at three initial concentrations (2.5, 5 and 10%) in order to counter water-soluble nickel (Ni) exceeding the Italian legal limit (10 μg L) in carbonation lime disposed of in a field and sampled for an 85-day lab study. The results show a noticeable reduction in water-soluble and bioavailable Ni in lime after the addition of sequestrants, especially at the dose of 5% bentonite or zeolite, thereby indicating a "ceiling effect" of the sequestrant, i.e., an increasing dose could reduce the adsorption capacity and be less effective. The alkaline pH and the presence of organic matter could be the main factors affecting the good performance of sequestrant addition, causing an increase in the negative charge of the organic and mineral colloids and the formation of unavailable Ni precipitates. The 85-day experiment seems to be sufficient to reach an adsorption equilibrium for water-soluble nickel, while for the bioavailable form a longer period appears to be necessary.
进行了一项实验室试验，以测试两种矿物质（膨润土和沸石）在三个初始浓度（2.5、5 和 10%）下的螯合容量，以应对碳酸石灰中水溶性镍（Ni）超过意大利法律限值（10μg/L）的情况，这些石灰被置于野外并取样进行为期 85 天的实验室研究。结果表明，在添加螯合剂后，石灰中的水溶性和生物可利用性 Ni 明显减少，特别是在 5%膨润土或沸石的剂量下，表明螯合剂存在“上限效应”，即增加剂量可能会降低吸附能力且效果较差。碱性 pH 值和有机物的存在可能是影响螯合剂添加性能的主要因素，导致有机和矿物胶体的负电荷增加，并形成不可用的 Ni 沉淀物。85 天的实验似乎足以达到水溶性镍的吸附平衡，而对于生物可利用形式，似乎需要更长的时间。
