Fe对土壤As活性的影响及作用机理研究进展

Research Progress on the Effect and Mechanism of Fe on Soil As Activity

砷(As)是仅次于镉(Cd)的第二大农田重金属污染物.As在土壤中具有多种价态,且土壤As的不同存在形态受土壤pH值、Eh值、中微量元素等因子的影响,而具有不同的环境效应.其中,铁(Fe)对As具有强亲和性,可生成难溶的沉淀,具有良好的固As能力.因此,综合当前国内外研究结果,详细阐述了土壤As的形态及生物有效性、铁氧化物和铁盐对土壤As的钝化效果及作用机理,从土壤pH值、Eh值、共存离子、铁盐用量及类型等方面对Fe固化As的效果及影响机制进行了归纳总结,并对当前用含Fe材料固As研究中存在的问题进行探讨,对研究方向进行了展望,为As污染农田的修复治理,尤其是含Fe材料修复As污染土壤提供科学指导.

Arsenic (As) is the second largest heavy metal pollutant in farmland after cadmium (Cd). As has many valence states in soil, and the different forms of As in soil are affected by soil pH, Eh value, trace elements and other factors, resulting in different environmental effects. While, iron (Fe) has strong affinity for As, can produce insoluble precipitation due to its good As fixation capacity. Based on the current research results at home and abroad, the morphology and bioavailability of As in soil, the passivation effect of iron oxides and iron salts on As in soil and its mechanism are elaborated in detail. The effects and influencing mechanism of Fe-As in soil are summarized from the aspects of soil pH, Eh, coexisting ions, and the amount and type of iron salts, also the existing problems in the current research of Fe-containing materials are summarized. The research direction is prospected to provide scientific guidance for the remediation of Ascontaminated farmland, especially for the remediation of As-contaminated soil with Fe-containing materials.