INDUROT, Environmental Technology, Biotechnology, and Geochemistry Group, Universidad de Oviedo, Campus de Mieres, 33600 Mieres, Asturias, Spain.
IMIDRA, Instituto Madrileño de Investigación y Desarrollo Rural, Agrario y Alimentación, Finca "El Encín", Alcalá de Henares, 28800, Madrid, Spain.
Chemosphere. 2020 Jan;238:124624. doi: 10.1016/j.chemosphere.2019.124624. Epub 2019 Aug 22.
The capacity of two iron-based nanomaterials, namely goethite nanospheres (nGoethite) and zero valent iron nanoparticles (nZVI), to immobilize As in a polluted soil was evaluated and compared. The composition and morphology of the products were studied by energy dispersive X-ray analysis and transmission electron microscopy, while zeta potential and average sizes were determined by dynamic light scattering. To assess As immobilization, soil subsamples were treated with nGoethite or nZVI at a range of Fe doses (0.5%, 2%, 5% and 10%) and then studied by the TCLP test and the Tessier sequential extraction procedure. The influence of both nanoparticles on As speciation was determined, as was impact on soil pH, electrical conductivity, Fe availability and phytotoxicity (watercress germination). For nZVI, notable results were achieved at a dose of 2% (89.5% decrease in As, TCLP test), and no negative effects on soil parameters were detected. Indeed, even soil phytotoxicity was reduced and only at the highest dose was a slight increase in As detected. In contrast, excellent results were obtained for nGoethite at the lowest dose (0.2%) (82.5% decrease in As, TCLP test); however, soil phytotoxicity was increased at higher doses, probably due to a marked enhancement of electrical conductivity. For both types of nanoparticle, slight increases in Fe availability were observed. Thus, our results show that both nZVI and nGoethite have the capacity to effectively immobilize As in this brownfield. The use of lower doses of nGoethite emerges as a promising soil remediation strategy for soils affected by As pollution.
评估并比较了两种基于铁的纳米材料（针铁矿纳米球（nGoethite）和零价铁纳米颗粒（nZVI））在污染土壤中固定砷的能力。通过能谱分析和透射电子显微镜研究了产物的组成和形态，通过动态光散射法测定了动电电位和平均粒径。为了评估砷的固定化，用 nGoethite 或 nZVI 处理土壤亚样本，铁剂量范围为 0.5%、2%、5%和 10%，然后通过TCLP 测试和 Tessier 连续提取程序进行研究。确定了两种纳米颗粒对砷形态的影响，以及对土壤 pH 值、电导率、铁可用性和植物毒性（西洋菜发芽）的影响。对于 nZVI，在 2%的剂量下（TCLP 测试中砷减少 89.5%）取得了显著的结果，且未检测到对土壤参数的负面影响。事实上，即使土壤植物毒性降低，仅在最高剂量下才检测到砷的轻微增加。相比之下，在最低剂量（0.2%）下，nGoethite 取得了优异的结果（TCLP 测试中砷减少 82.5%）；然而，在更高剂量下，土壤植物毒性增加，可能是由于电导率的显著增强。对于这两种类型的纳米颗粒，都观察到铁可用性的轻微增加。因此，我们的结果表明，nZVI 和 nGoethite 都有能力有效地固定这种棕色地带中的砷。使用较低剂量的 nGoethite 作为受砷污染土壤的土壤修复策略具有广阔的前景。
