Effects of α-Fe2O3 modified chicken manure biochar on the availability of multiple heavy metals and soil biochemical properties

作者：Li, Yingchao; Yin, Hua^*; Guo, Zhanyu; Zhu, Minghan; Yan, Caiya; Li, Xiaoqin; Dang, Zhi

来源：Journal of Environmental Chemical Engineering, 2023, 11(3): 109922.

DOI：10.1016/j.jece.2023.109922

• alpha-Fe2O3
• Biochar
• Heavy metals
• Soil amendment

The problem of increasingly severe soil heavy metals contamination is of great concern worldwide. Herein, chicken manure and potassium ferrocyanide were used as raw materials to prepare a alpha-Fe2O3 loaded biochar (Fe2O3/BC) composite material through a simple calcination method. We found Fe2O3/BC obtained at 350 degrees C (Fe2O3/BC-350) exhibited excellent immobilization efficiency on multiple heavy metals in soil. And then density functional theory (DFT) calculations explained the reason of Fe2O3/BC-350 exhibited better remediation performance than the Fe2O3/BC-250 and Fe2O3/BC-550. When cultured for 90 days, the passivation effect of the 1% Fe2O3/BC-350 dosage treatment achieved the highest with the immobilization rates for Cu(II), Cd(II) and Pb(II) reaching 62.5%, 45.56% and 42.56%, respectively. The composite material increased soil pH and cation exchange capacity (CEC), and promoted the transformation of Cu(II), Cd(II) and Pb(II) ions from acid-soluble to more stable forms through ion exchange, precipitation and complexation. The soybean pot experiment further verified that Fe2O3/BC-350 could reduce the phytoavailable fractions of heavy metal soil remediation material. In addition, Fe2O3/BC-350 increased the activity of soil urease and sucrase. Meanwhile, the diversity and richness of the soil microbial community were improved. These results demonstrated that Fe2O3/BC-350 not only had an excellent immobilization effect on heavy metals in the soil, but also Fe2O3/BC-350 exhibited environmentally friendly in soil. As a result, Fe2O3/BC can serve as a promising remediation agent for multiple heavy metal polluted soils.