生物炭协同微生物矿化技术修复复合重金属污染农田土壤

以复合重金属污染农田土壤为研究对象,采用生物炭协同微生物矿化修复技术修复复合重金属污染农田土壤。通过调查污染区重金属含量及营养指标分布情况,验证生物炭协同微生物矿化修复技术对复合形态的Pb、Zn、Cd三种重金属的固定效率,同时采取添加钙组和不添加钙的实验方式,解析Ca和Cd竞争成核位点的机制。结果表明:污染区属于Pb、Zn、Cd三种重金属复合污染场地,且土壤养分含量N、P、K等级分布不均匀。处理组较空白组重金属Pb、Zn、Cd的浸出率分别降低了42.49%、45.95%、30.43%,重金属Pb、Cd的可交换态分别下降了25.06%、26.42%,显著降低了土壤中重金属的迁移转化。且生物炭协同微生物矿化修复技术可有效改善土壤的物理结构,导气性及导水性升高,降低土壤容重,同时提升了土壤氮磷钾、有机质等营养指标。该研究为复合重金属污染农田土壤规模化治理提供了科学依据和理论参考。

Remediation of farmland soil polluted by complex heavy metals by biochar combined with microbial mineralization

In this study, the compound heavy metal contaminated farmland soil was taken as the research object, and biochar combined with microbial mineralization remediation technology was used to repair the compound heavy metal contaminated farmland soil. By investigating the content of heavy metals and the distribution of nutritional indicators in the polluted area, the fixation efficiency of biochar assisted microbial mineralization and remediation technology for three kinds of heavy metals, Pb, Zn and Cd, in composite form, was verified. At the same time, the experimental method of adding calcium group and not adding calcium was adopted to analyze the mechanism of competition between Ca and Cd nucleation sites. The results indicate that the polluted area belongs to a complex pollution site of Pb, Zn, and Cd heavy metals, and the distribution of soil nutrient content N, P, and K levels is uneven. The leaching rates of heavy metals Pb, Zn, and Cd in the treatment group decreased by 42.49%, 45.95%, and 30.43%, respectively, compared to the blank group. The exchangeable states of heavy metals Pb and Cd decreased by 25.06% and 26.42%, respectively, significantly reducing the migration and transformation of heavy metals in the soil. Moreover, the biochar assisted microbial mineralization remediation technology can effectively improve the physical structure of soil, increase the gas conductivity and water conductivity, reduce the soil bulk density, and improve the soil nitrogen, phosphorus, potassium, organic matter and other nutritional indicators. This study provides a scientific basis and theoretical reference for the large-scale treatment of farmland soil contaminated by composite heavy metals.