秸秆生物炭修复电镀厂污染土壤的效果和作用机理初探

以某电镀厂污染场地重污染区域土壤为研究对象,利用秸秆生物炭对污染土壤进行稳定化试验,研究不同生物炭添加量(0、10、30、50、70和100 g.kg-1)条件下土壤中重金属全量和形态变化。结果表明,秸秆生物炭能够改变污染土壤中重金属的形态分布,对该污染土壤有明显的稳定化作用。其中对铬的作用效果最明显,随生物炭添加量的增加,残渣态铬含量明显上升,100 g.kg-1生物炭添加量处理残渣态铬含量较对照(1 098.75 mg.kg-1)增幅最大,增加59.51 mg.kg-1;对铜和镍的稳定化效果受添加量的影响,当生物炭添加量分别在70和30g.kg-1以上时,对铜和镍有一定稳定化作用;对该污染土壤中锌则无明显稳定化作用。当生物炭添加量为50 g.kg-1时,4种重金属残渣态总量较对照(1 745 mg.kg-1)明显增加,为1 805.95 mg.kg-1,添加量也较为合理。

Effects and Mechanisms of Straw Biochar on Remediation Contaminated Soil in Electroplating Factory

Soil samples were collected from a heavily contaminated zone in an electroplating plant site for stabilization test using biochar derived from straw.Variation of the heavy metals in amount and form with the rate of biochar amended into the soil was analyzed.Results show that biochar changed the forms and distribution of heavy metals in the soil and had some significant effect stabilizing the polluted soil,particularly on Cr.With increasing biochar amendment rate,the content of residual form of Cr increased significantly.Especially in the treatment of 100 g·kg-1 biochar,the content of residual Cr increased by 59.51 mg·kg-1,as compared with that in CK(1 098.75 mg·kg-1),being the largest increment.The effect of stabilizing Cu and Ni was closely related to biochar amendment rate: when biochar was added up to or over 70 and 30 g·kg-1,its remediation effect on Cu and Ni was quite obvious,but not on Zn in the soil.When biochar amendment rate was 50 g·kg-1,the total content of the 4 heavy metals(Cu,Cr,Ni and Zn) in residual form increased up to 1 805.95 mg·kg-1,much higher than 1 745 mg·kg-1 in CK.The biochar amendment rate was quite reasonable.