【摘要】 本文以铁铈氧化物(Fe-Ce,FC)为研究对象,评估其对中国3种典型砷(As)污染土壤的稳定化修复效果,并通过电子扫描显微镜能散X线分析仪(SEM-EDS)和X射线光电子能谱仪(XPS)等光谱学技术探索FC对As(Ⅴ)的微观吸附特征.结果表明,FC能使土壤毒性浸出As含量显著降低84. 1%～98. 3%,且在碱性土壤中表现出较强的高p H适应性,能显著增加吸附态As(F1+F2)向水合铁铝氧化物结合态(F3+F4)的稳定化. FC能使不同类型土壤的有效态P含量显著下降47. 13%～60. 32%,不仅能缓解P竞争土壤As(Ⅴ)吸附位点,而且能有效预防周边水体的面源污染.通过SEM-EDS和XPS分析,发现As(Ⅴ)吸附产物表面均检测到Fe、Ce和As这3种元素,且As主要吸附于Fe原子表面. FC在我国土壤砷污染稳定化修复领域具有较好地应用前景.更多还原

【Abstract】 The mining and smelting of arsenic-containing metal minerals,and the large-scale use of chemicals and pesticides,has resulted in the widespread pollution of soils in southwestern and southern China. In this study,the stabilizing effect of Fe-Ce oxide( FC) on three representative arsenic-contaminated soils was evaluated. The microscopic adsorption characteristics of FC and As( Ⅴ)were explored by scanning electron microscopy and energy disperse spectroscopy( SEM-EDS) and X-ray photoelectron spectroscopy( XPS). The results showed that FC can significantly reduce arsenic concentrations by 84. 1%-98. 3% during the Toxicity Characteristic Leaching Procedure( TCLP),and showed strong p H adaptability in alkaline soil. It efficiently transformed( non-)specifically sorbed arsenic( F1 + F2) into hydrous oxides phases of Fe and Al( F3 + F4). FC also significantly reduced available P by47. 13%-60. 32% in different types of soil. FC can not only release As( Ⅴ) adsorption sites occupied by P in soils,but also effectively prevents non-point source pollution of the surrounding water. SEM-EDS and XPS analysis detected Fe,Ce,and As on the surface of As( Ⅴ) adsorption products,and As was mainly adsorbed on the surface of Fe atoms. The results of this study provide a scientific basis for soil arsenic stabilization in China.更多还原