改性生物炭土壤钝化试验研究

Experimental Study on Soil Passivation of Modified Biochar

摘要: 秸秆作为基体原料，具有来源广零成本和避免其焚烧引起大气污染等优点。制备出改性后的钝化材料PFBC和KFBC，采用SEM-EDS、FTIR、XRD测试手段，对钝化材料样品的化学成分、形貌特征进行表征分析，并证明零价铁负载在改性材料。钝化预实验和土壤钝化实验结果表明，改性材料PFBC和KFBC较比于BC的钝化效果显著提高，其中KFBC钝化效果最佳。土壤钝化实验中，在钝化时间40天时，KFBC改性材料高投入量时钝化后土壤浸出上清液中砷、铬含量低于5 mg/kg。以实验结果为基础推测出钝化材料的反应机理：BC为吸附沉淀等作用；PFBC为氧化–还原和离子交换等作用；KFBC为氧化–还原和表面沉淀等作用。

Abstract: As a substrate raw material, straw has the advantages of zero cost from the source and avoiding air pollution caused by its incineration. The modified passivated materials PFBC and KFBC were prepared, and the chemical composition and morphological characteristics of the passivated material samples were characterized and analyzed by SEM-EDS, FTIR, XRD test methods, and the zero-valent iron load was proved in the modified materials. The passivation pre-experiment and soil passivation experiment showed that the passivation effect of PFBC and KFBC of the modified materials was significantly improved compared with BC, and the passivation effect of KFBC was the best. In the soil passivation experiment, at the passivation time of 40 days, the arsenic and chromium content in the supernatant leached from the soil after passivation of KFBC modified materials was less than 5 mg/kg. Based on the experimental results, the reaction mechanism of the passivated material is inferred: BC is the role of adsorption precipitation, and so on; PFBC is for oxidation-reduction and ion exchange and other functions; KFBC is responsible for oxidation-reduction and surface precipitation.