毛竹遗态Fe/C复合材料对As(Ⅴ)污染土壤的钝化修复性能

Remediation Performance via the Passivation of a Porous Biomorph Genetic Composite ofα-FeO/FeO/C Using a Bamboo Template on As(Ⅴ)Contaminated Soils

选择广西红壤为背景土壤,以自制毛竹遗态Fe/C复合材料(PBGC-Fe/C)为钝化剂,对As(Ⅴ)污染土壤进行钝化修复,结合扫描电镜(SEM)、X射线衍射(XRD)和红外光谱(FT-IR)的表征结果对钝化机制展开分析.结果表明:PBGC-Fe/C能有效钝化修复高浓度As(Ⅴ)污染土壤,在投加比例为5%、含水量为25%和材料粒径为100目的条件下,PBGC-Fe/C对500mg·kg^-1和1000 mg·kg^-1As(Ⅴ)污染土壤的稳定率分别可达80.95%和73.49%;毛竹炭遗态结构有吸附点位多的优势,酸性条件有利于土壤中As(Ⅴ)的钝化.PBGC-Fe/C不仅可吸附固定砷,同时可促使砷的形态转向稳定化,化学络合和离子交换在钝化修复过程中起主要作用.

Red soil from Guangxi,China was selected as the background soil,and a porous biomorphic genetic composite ofα-Fe2O3/Fe3O4/C comprising a bamboo template(PBGC-Fe/C)was used as a passivator to remediate As(Ⅴ)contaminated soils.The performance of PBGC-Fe/C was characterized by Scanning electron microscopy(SEM),X-ray diffraction(XRD),and Fouriertransform infrared spectroscopy(FT-IR).The results showed that PBGC-Fe/C could improve the passivation effect of As(Ⅴ)from the contaminated soils compared with a single passivation material.Under the conditions of a 5%dose addition,25%water content,and particle size of 100 mesh,the stability rates of PBGC-Fe/C on As(Ⅴ)contaminated soils with different concentrations of 500 mg·kg^-1 and 1000 mg·kg^-1 could reach 80.95%and 73.49%,respectively.The porous biomorphic genetic composite of bamboo charcoal provided a large number of adsorption sites for As(Ⅴ),and the acidity of the soil was favorable for the remediation of As(Ⅴ)via passivation.Moreover,PBGC-Fe/C could not only adsorb and fix As(Ⅴ),but also promoted the stabilization of As species.Chemical complexation and ion exchange played major roles in this passivation process.