磷改性生物炭对Pb、Cd复合污染土壤的钝化效果

The passivation effect of Pb,Cd composite polluted soil by phosphorus-modified biochar

中国存在着较大面积受重金属污染土壤,尤其是Pb、Cd两种重金属的复合污染较常见。利用磷改性生物炭对Pb、Cd复合污染土壤展开修复研究。结果表明:(1)磷改性生物炭可使土壤中Pb、Cd由弱酸提取态向可氧化态、残渣态转变,Pb的可氧化态和残渣态分别增加了19.4、16.9百分点,Cd的可氧化态、残渣态分别增加了17.4、9.9百分点;(2)磷改性生物炭可提高土壤有效磷,有效磷最终稳定在39 mg/kg左右;(3)磷改性生物炭能显著增加土壤阳离子交换量至19.3 cmol/kg。磷改性生物炭不仅能有效钝化重金属,还能有效改善土壤质量。

There was a relative large area of heavy metal contaminated soil in China,the Pb,Cd combined pollution was common,so the phosphorus modified biochar was used in this kind of heavy metal contaminated soil remediation in this research. The experimental results indicated that:( 1) Phosphorus modified biochar could lower weak acid dissolvable heavy metal contents and enhance oxidizable and residual heavy metal contents in soil,the oxidation state and residual state of lead increased 19.4,16.9 percent point,respectively,the oxidation state and residual state of cadmium increased 17.4,9.9 percent point,respectively.( 2) Phosphorus modified biochar could also increase the content of available phosphorus in soil,the content of available phosphorus in soil reach up to 39 mg/kg.( 3) Phosphorus modified biochar could significantly increase soil cation exchange capacity up to 19.3 cmol/kg. The phosphorus modified biochar could passivate heavy metal and improve the quality of the soil effectively.