污泥与污泥生物炭对比修复铜、镉污染土壤

Restoration of Cu and Cd heavy metal contaminated soil by sludge and sludge-derived biochar

探讨污泥和污泥生物炭(SDBC)修复铜(Cu)、镉(Cd)复合污染土壤的效果,在模拟的Cu、Cd复合污染土壤中按照1%,5%,10%的质量比例分别施加污泥与SDBC,对比分析土壤中Cu、Cd总量及形态分配的变化。结果显示,污泥与SDBC施用后,会造成土壤中重金属含量升高,但添加污泥和SDBC不同程度地降低重金属的弱酸提取态和可还原态占比,提高可氧化态和残渣态占比,有效降低Cu、Cd在土壤中的迁移性和可生物利用性。对Cu和Cd修复效果最好的污泥和SDBC添加比例分别为5%和10%,Cu在添加比例为5%质量分数的污泥处理后,弱酸提取态占比降低26.80%,残渣态占比增长60.39%;而在添加10%SDBC后,可还原态占比降低77.21%,可氧化态占比增长175.52%。Cd在5%污泥处理下的残渣态占比增幅为25.49%,10%SDBC处理,使可氧化态占比增幅达153.17%。污泥与SDBC可用于Cu、Cd重金属污染土壤的修复,且10%SDBC施用比5%污泥施用修复效果好。

The different amounts(1%,5%,10%)of sludge and sludge-derived biochar(SDBC)were added to the Cu and Cd compound contaminated soil to study the feasibility of using them as passivation agent.Then the transformation of morphology distribution of Cu and Cd in soil were compared and analyzed.The results showed that sludge and SDBC increased the content of heavy metals in soil while reduced the acid extractable state and reducible state contents of heavy metals and increased the oxidized state and residue state contents to different degrees from the respect of morphological transformation,which reduced the mobility and bioavailability of Cu and Cd.The ratios of 5%and 10%were the optimal amount of addition of sludge and SDBC,respectively.The acid extractable state of Cu in the 5%sludge treatment group decreased by 26.80%,while the residue state increased by 60.39%.With the treatment group of the 10%SDBC,there was a reduce of 77.21%for the reducible state and an increase of 175.52%for the oxidized state.As for Cd,the residue state proportion was increased by 25.49%with the 5%sludge treatment while the proportion of oxidized state was increased by 153.17%with the 10%SDBC.Sludge and SDBC can be used for the remediation of Cu and Cd contaminated soil,and the effect of 10%SDBC is better than 5%sludge.