不同粒径生物炭对黔西北土法炼锌区土壤重金属污染修复效果研究

Effect of biochar with different particle size on remediation of soil heavy metal pollution in native zinc smelting area in northwest of Guizhou province

为了探究生物炭对土壤的理化性质及典型重金属(Pb、Zn和Cd)钝化修复效果的影响,实验对竹子茎生物炭(700℃)进行不同粒径(BC1:0.5~1 mm、BC2:1~3 mm、BC3:3~5 mm)处理,向供试土壤加入质量分数为1%不同粒径的生物炭,通过土壤培育实验,分析生物炭添加对污染土壤的理化性质及重金属钝化修复的影响。实验结果表明,同空白对照组相比,向供试土壤加入生物炭后:土壤的pH、有机质及全磷含量均减小,导电率均增加,阳离子交换量无明显变化规律;对Pb、Zn和Cd的形态分布产生影响,使其向更稳定的形态变化,其中Pb的可氧化态占比升高,Zn和Cd的残渣态占比升高;除添加BC1和BC2会使Pb钝化修复效率降低且潜在风险指数(PRI)增大外,均能提高Pb、Zn和Cd的修复效率,降低其在土壤中的生物有效性,从而减轻重金属对土壤环境的危害。

In order to explore the effects of biochar on soil physical and chemical properties and passivation of typical heavy metals(Pb,Zn and Cd),bamboo stem biochar(700℃)was treated with different particle sizes(BC1:0.5~1 mm,BC2:1~3 mm,BC3:3~5 mm),then 1%biochar with different particle sizes was added to the tested soil to analyz the effects of biochar addition on the physical and chemical properties and heavy metal passivation remediation of contaminated soil through soil cultivation experiment.The experimental results showed that compared with the blank control group:The pH,organic matter and total phosphorus contents of the soil decreased,the electrical conductivity increased,and the cation exchange capacity had no obvious change rule.The morphology distribution of Pb,Zn and Cd has changed to a more stable form.The proportion of oxidized state of Pb increased,and the proportion of residual state of Zn and Cd increased.The addition of BC1 and BC2 can reduce the passivation restoration efficiency of Pb and increase the potential risk index(PRI),while improving the restoration efficiency of Pb,Zn and Cd and reducing bioavailability in soil,thus reducing the harm of heavy metals to the soil environment.