Soil Geography/Soil Science, Department of Geosciences, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany.
Chemosphere. 2013 Nov;93(9):2108-15. doi: 10.1016/j.chemosphere.2013.07.055. Epub 2013 Aug 22.
Steel slags are industrial by-products which are generated in large amounts worldwide, e.g. 150-230×10(6) Mg in 2012, and which are partly used for construction. Molybdenum (Mo) can be added during steel processing in order to harden the steel. The objective of this study was to evaluate the adsorption behaviour of molybdate (MoO4(2-)) from slag eluates in subsoils. Molybdate batch adsorption experiments were carried out with eluates obtained from two different kinds of steel slags (i) LD slag (Linz-Donawitz operation, LDS) and (ii) electric arc furnace slag (EAF) to assess the risk that may arise from the contamination of groundwater by the leaching of molybdate. Six different subsoils were chosen in order to provide a wide range of chemical properties (pH 4.0-7.6; dithionite-extractable Fe 0.73-14.7 g kg(-1)). Molybdate adsorption experiments were carried out at the pH of the steel slag eluates (pH 11-12) as well as at pH values adjusted to the soil pH. The data were evaluated with the Freundlich equation. Molybdate adsorption exhibited a maximum near pH 4 for steel slag eluates adjusted to the soil pH, and decreased rapidly with increasing pH until adsorption was virtually zero at pH>11. Adsorption was greater for soils with high amounts of dithionite-extractable Fe oxides. The extent and behaviour of molybdate adsorption from both eluates was similar. After a reaction time of 24h, the pH of the EAF slag eluate was lower than that of the LD steel slag eluate, which was caused by different acid buffer capacities. Some soils were able to decrease the pH of the EAF slag eluates by about 4 pH units, enhancing the adsorption of molybdate. Transport simulations indicated that molybdate discharge is low in acidic soils.
钢渣是一种工业副产品，在全球范围内大量产生，例如在 2012 年产生了 150-230×10(6) Mg，其中一部分用于建筑。在炼钢过程中可以添加钼（Mo）以提高钢的硬度。本研究的目的是评估从渣浸出液中吸附亚土中钼酸盐（MoO4(2-）的行为。使用从两种不同类型的钢渣（i）LD 渣（林茨-多纳维茨操作，LDS）和（ii）电弧炉渣获得的浸出液进行钼酸盐批量吸附实验，以评估因浸出钼酸盐而污染地下水的风险。选择了六种不同的亚土，以提供广泛的化学性质（pH 4.0-7.6；二硫代碳酸盐可提取铁 0.73-14.7 g kg(-1））。在钢渣浸出液的 pH（pH 11-12）以及调整为土壤 pH 的 pH 值下进行钼酸盐吸附实验。用 Freundlich 方程评价数据。对于调整为土壤 pH 的钢渣浸出液，钼酸盐吸附在 pH 近 4 时表现出最大吸附，随着 pH 的增加迅速下降，直到 pH>11 时吸附几乎为零。对于二硫代碳酸盐可提取铁氧化物含量较高的土壤，吸附作用更强。两种浸出液的钼酸盐吸附程度和行为相似。反应 24h 后，EAF 渣浸出液的 pH 低于 LD 钢渣浸出液，这是由于不同的酸缓冲能力所致。一些土壤能够将 EAF 渣浸出液的 pH 降低约 4 个单位，从而增强钼酸盐的吸附。运移模拟表明，钼酸盐在酸性土壤中的排放量较低。
