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土壤中As的不同存在形态影响着其毒性、可移动性、生物有效性,且产生不同的环境影响.本研究以粉煤灰、干化污泥、硫酸亚铁、碎花生壳为稳定剂,探讨其对土壤As的稳定化效果以及p H、有机质和阳离子交换量与土壤As形态的关系.结果表明添加稳定剂后,土壤p H及有机质含量上升,残渣态砷含量升高.添加10%粉煤灰、10%干化污泥后,可交换态As、碳酸盐结合态As、铁锰氧化物结合态As、有机结合态As分别下降了34.2%、17.5%、19.9%、53.7%,并转化为残渣态As,其含量增长了1.14%.当同时添加10%粉煤灰、10%干化污泥和1%硫酸亚铁后,土壤中可交换态As、碳酸盐结合态As、铁锰氧化物结合态As、有机结合态As含量的降幅分别为62.3%、55.2%、29.6%、58.2%,残渣态As含量增加8.1%.添加10%粉煤灰、10%干化污泥、1%硫酸亚铁和1%粉碎花生壳后,可交换态As下降最显著,最大降幅为73.3%.施用适量的粉煤灰、干化污泥、硫酸亚铁能使土壤中的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态As的一部分转化为残渣态As,降低其毒性.提高p H,残渣态As含量上升,可交换态As、碳酸盐结合态As、铁锰结合态As、有机结合态As含量下降,As在接近中性的环境中稳定性最好;提高有机质含量,碳酸盐结合态As与残渣态As含量上升,可交换态As、铁锰结合态As、有机结合态As含量下降,有机结合态As含量下降明显;阳离子交换量上升,残渣态As含量上升,可交换态As、碳酸盐结合态As、铁锰结合态As、有机结合态As含量下降.
Different forms of As in soils affect their toxicity, mobility and bioavailability, and have different environmental impacts.In this study, fly ash, dried sludge, ferrous sulfate and peanut shells were used as stabilizers , And discussed the effect of stabilizing As on soils and the relationship between p H, organic matter and cation exchange capacity and As forms of soil.The results showed that the content of p H and organic matter increased and the content of residual arsenic increased after the addition of stabilizer % Fly ash and 10% dry sludge, exchangeable As, carbonate bound As, Fe-Mn oxide bound As and organic bound As decreased by 34.2%, 17.5%, 19.9% and 53.7% respectively % And converted to residual As, the content increased by 1.14% .When 10% fly ash, 10% dry sludge and 1% ferrous sulfate were added at the same time, the exchangeable As and carbonate in the soil As, As and Fe, Mn, As and As in organic-bound As were decreased by 62.3%, 55.2%, 29.6% and 58.2%, respectively, and As content increased by 8.1% After the sludge, 1% ferrous sulfate and 1% crushed peanut shells, the exchangeable As decreased the most significantly, the maximum decrease was 73.3% Ash, dried sludge and ferrous sulfate can convert a part of exchangeable, carbonate-bound, Fe-Mn oxide-bound and organic-bound As in the soil to residual As and decrease the toxicity of p H, the content of As in the residue increased, the exchangeable As, carbonate bound As, Fe-Mn bound As and organic-bound As decreased, As showed the best stability in nearly neutral environment; The contents of As and CO in the carbonate bound and the residual As increased, the content of exchangeable As, Fe and Mn bound As and organic bound As decreased, while the content of organic bound As decreased significantly. The cation exchange capacity increased, Exchangeable As, carbonate-bound As, Fe-Mn bound As and organic-bound As decreased.