Sorption of oxyanions, such as pentavalent vanadium (V(V)), by reactive, poorly crystallized clay minerals and Fe-(hydr)oxides surfaces significantly contributes to the nutrient and pollutant transport in soils. However, only a few studies yet exist, which evaluate and quantify the role of such common soil substituents on V sorption. In this contribution, the uptake of V(V) by allophane with molar Al/Si ratios of 1.5 (ALO-1) and 1.8 (ALO-2) and by montmorillonite-beidellite (MNT-BEI) clays was investigated using kinetic and equilibrium experiments. The effects of pH, V speciation, contact time and presence of 6-line ferrihydrite (FHY) were evaluated at 25 °C. The clayey substrates with(out) FHY were characterized using X-ray diffraction, X-ray fluorescence, high-resolution transmission electron microscopy with energy-dispersive X-ray spectroscopy and selected area electron diffraction and N₂-Brunauer-Emmett-Teller physisorption methods. Fast (≥ 15 min) adsorption of V(V) was followed by pseudo-first-order reaction kinetics and progressed through instantaneous diffusion processes at the exterior surface. Subsequently, V(V) transportation and adsorption within the interior substrate, as inferred from Weber-Morris intra-particle diffusion model plots, was observed. The presence of FHY had a positive effect on V(V) adsorption ([V]_T = 0.02 mmol/L), which followed in the order MNT-BEI-FHY and MNT-BEI (≥ 95% removal), ALO-1-FHY and ALO-2-FHY (≥ 90% removal), ALO-1 (≥ 70% removal) and ALO-2 (≥ 40% removal) in the pH range from ~6 to ~8. The results of this study demonstrate the high affinity of ferrihydrite as well as allophanic and smectitic clays for V(V) adsorption, suggesting that these components can limit the V mobility in soils over a wide pH range.

氧阴离子，如五价钒 (V(V))，通过反应性、结晶差的粘土矿物和 Fe-(氢) 氧化物表面对土壤中的养分和污染物运输有显着贡献。然而，目前只有少数研究评估和量化了这些常见土壤取代物对 V 吸附的作用。在此贡献中，使用动力学和平衡法研究了摩尔 Al/Si 比为 1.5 (ALO-1) 和 1.8 (ALO-2) 的水铝英石和蒙脱石-贝得石 (MNT-BEI) 粘土对 V(V) 的吸收实验。在 25 °C 下评估了 pH、V 形态、接触时间和 6 线水铁矿 (FHY) 存在的影响。使用 X 射线衍射、X 射线荧光、₂ -Brunauer-Emmett-Teller 物理吸附方法。V(V) 的快速（≥ 15 分钟）吸附之后是准一级反应动力学，并通过外表面的瞬时扩散过程进行。随后，观察到从 Weber-Morris 粒子内扩散模型图中推断出的内部基板内的 V(V) 传输和吸附。FHY 的存在对 V(V) 吸附 ([V] _T = 0.02 mmol/L), 依次为 MNT-BEI-FHY 和 MNT-BEI (≥ 95% 去除), ALO-1-FHY 和 ALO-2-FHY (≥ 90% 去除), ALO-1 ( ≥ 70% 去除）和 ALO-2（≥ 40% 去除）在 pH 值范围从 ~6 到 ~8。这项研究的结果证明了水铁矿以及脲基和蒙脱石粘土对 V(V) 吸附的高亲和力，这表明这些组分可以在较宽的 pH 值范围内限制土壤中的 V 迁移率。