污泥生物炭对土壤中Pb和Cd的生物有效性的影响

以污泥为原料，在500 ℃缺氧条件下制备污泥生物炭，结合X射线能谱（EDS）、环境扫描电镜（SEM）和红外光谱（FTIR）等表征手段，分析添加污泥生物炭后污染土壤pH和Pb与Cd化学形态的变化来探究污泥生物炭对土壤中Pb、Cd的固定效果，并用盆栽方式评估添加污泥生物炭对小青菜生物量及体内重金属含量的影响。结果表明：添加污泥生物炭后，污染土壤的pH随平衡时间的延长显著升高；对于单一污染土壤和复合污染土壤，污泥生物炭对Pb和Cd均有较强的固定作用，而污泥生物炭在复合污染土壤中对Pb的固定效果优于在单一污染土壤中；添加污泥生物炭能提高小青菜的生物量，且能有效降低小青菜对污染土壤中Pb和Cd的吸收。

Remediation of Pb and Cd contaminated soil by sludge biochar

Sludge biochar was prepared under anoxic conditions at 500℃ using sludge as raw materials. Combined with EDS, SEM and FTIR, immobilization and remediation effect of sludge biochar on Pb and Cd were investigated by analyzing the variation of pH and heavy metal chemical speciation in contaminated soil after adding sludge biochar. The experiment of potted vegetable was used to assess the influence of adding sludge biochar on the biomass and the heavy metal contents of vegetables. The results show that after adding sludge biochar, the value of pH increased significantly with the increase of the equilibrium time;sludge biochar has a strong immobilization effect for both Pb and Cd either on single or on multi-polluted soil, and sludge biochar has a stronger immobilization effect for Pb on multi-polluted soil than on single polluted soil. Besides, adding sludge biochar can increase the biomass of vegetables and reduce the absorption of Pb and Cd effectively in contaminated soil.