Mechanism, efficiency and environmental impact of biochar in soil remediation

Soil pollution resulting from the accumulation of heavy metals, pesticides, and organic pollutants is a global concern. This review article explores biochar as an effective method for soil remediation, with a particular focus on its role in the immobilization of heavy metals, reduction of pesticide toxicity, enhancement of soil fertility, and stimulation of microbial activity. The high specific surface area and porous structure of biochar make it a highly efficient biomaterial for reducing pollutant activity and improving soil quality. The review also highlights the important role of biochar in carbon sequestration and mitigating the effects of climate change, thereby supporting sustainable agricultural practices. Key aspects discussed include the application rate and depth of biochar incorporation into the soil, its impact on crop yield across different soil types, and its contribution to ecosystem improvement. Additionally, biochar enhances microbial activity, regulates nutrient cycling and organic matter decomposition, improves soil structure, increases water retention capacity and cation exchange capacity (CEC), maintains soil fertility, and reduces susceptibility to erosion. Thus, the potential of biochar in sustainable agriculture and environmental management is evident, and numerous studies emphasize its significant role in improving soil quality and mitigating the impacts of soil pollution.

1. Food and Agriculture Organization of the United Nations (FAO). The future of food and agriculture: Trends and challenges. – Rome: FAO, 2017.

2. Liu Y., Chen Z., Wang L., Zhang H. Heavy metal contamination in agricultural soils and its impact on food safety in China: A review// Environmental Pollution. – 2022. – Vol. 301. – P. 119026.

3. Li J., Sun R., Huang Y., Zhao X. Impact of heavy metals on soil microbial diversity and agricultural productivity: Challenges and perspectives // Journal of Hazardous Materials. – 2023. – Vol. 443. – P. 130255.

4. Zhang C., Nie S., Liang J., Zeng G. Impacts of pesticide residues on soil microbial communities and ecosystem functions: A review // Chemosphere. – 2020. – Vol. 242. – P. 125535.

5. Kameyama K., Miyamoto T., Shiono T. Biochar application to contaminated soils: A promising strategy for soil remediation and carbon sequestration // Agriculture. – 2021. – Vol. 11, № 1. – P. 34.

6. Alloway B. J. Heavy metals in soils: Trace metals and metalloids in soils and their bioavailability. 3rd ed. – Springer, 2013.

7. Zhang M., Song W., Wang H. Influence of biochar on heavy metal speciation and bioavailability in soil: A review // Journal of Environmental Management. – 2019. – Vol. 232. – P. 123–130.

8. McGrath S. P., Zhao F. J., Lombi E. Plant and rhizosphere processes involved in phytoremediation of metal-contaminated soils // Plant and Soil. – 2015. – Vol. 232. – P. 207–214.

9. Li H., Dong X., da Silva E. B., de Oliveira L. M., Chen Y., Ma L. Q. Mechanisms of metal sorption by biochars: Biochar characteristics and modifications // Chemosphere. – 2020. – Vol. 246. – P. 125609.

10. Lehmann J., Rillig M. C., Thies J., Masiello C. A., Hockaday W. C., Crowley D. Biochar effects on soil biota – A review // Soil Biology and Biochemistry. – 2011. – Vol. 43, № 9. – P. 1812–1836.

11. Zhao L., Cao X., Mašek O., Zimmerman A. Heterogeneity of biochar properties as a function of feedstock sources and production temperatures // Journal of Hazardous Materials. – 2018. – Vol. 350. – P. 93–102.

12. Liang B., Lehmann J., Solomon D., Kinyangi J., Grossman J., O’Neill B., Skjemstad J. O., Thies J., Luizão F. J., Petersen J., Neves E. G. Black carbon increases cation exchange capacity in soils // Soil Science Society of America Journal. – 2006. – Vol. 70, № 5. – P. 1719–1730.

13. Clough T. J., Condron L. M., Kammann C., Müller C. A review of biochar and soil nitrogen dynamics // Agronomy. – 2013. – Vol. 3, № 2. – P. 275–293.

14. Jeffery S., Verheijen F. G. A., van der Velde M., Bastos A. C. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis // Agriculture, Ecosystems & Environment. – 2011. – Vol. 144, № 1. – P. 175–187.

15. Sohi S. P., Krull E., Lopez-Capel E., Bol R. A review of biochar and its use and function in soil // Advances in Agronomy. – 2010. – Vol. 105. – P. 47–82.

16. Gao S., DeLuca T. H., Cleveland C. C. Biochar additions alter phosphorus and nitrogen availability in agricultural ecosystems: A meta-analysis // Science of The Total Environment. – 2018. – Vol. 643. – P. 926–935.

17. Ameloot N., Graber E. R., Verheijen F. G. A., De Neve S. Interactions between biochar stability and soil organisms: Review and research needs // European Journal of Soil Science. – 2013. – Vol. 64, № 4. – P. 379–390.

18. Chen L., Xu S., Liu Y., Zhang W., Shen C. Effects of pyrolysis temperature on the properties of biochar and its adsorption behavior for heavy metals // Bioresource Technology. – 2021. – Vol. 329. – P. 124839.

19. Tan X., Liu Y., Zeng G., Wang X., Hu X., Gu Y., Yang Z. Biochar as potential sustainable precursors for activated carbon production: Multiple applications in environmental protection and energy storage // Bioresource Technology. – 2020. – Vol. 293. – P. 122070.

20. Wang S., Gao B., Zimmerman A. R., Li Y., Ma L. Q., Harris W. G. Removal of arsenic by magnetic biochar prepared from pinewood and natural hematite // Bioresource Technology. – 2021. – Vol. 299. – P. 122622.

21. Zhang X., Wang H., He L., Lu K., Sarmah A., Li J., Bolan N. S., Pei J., Huang H. Using biochar for remediation of soils contaminated with heavy metals and organic pollutan-ts // Environmental Science and Pollution Research. – 2020. – Vol. 27. – P. 22126–22141.

22. Mukherjee A., Lal R., Zimmerman A. R. Impacts of biochar and other amend-ments on the sorption and leaching of pharmaceuticals and personal care products from soils: A review // Science of The Total Environment. – 2021. – Vol. 757. – P. 143937.

23. Zhou Y., Gao B., Zimmerman A. R., Fang J., Sun Y., Cao X. Sorption of organic pollutants by biochars: Sorption mechanisms, influencing factors, and environmental implications // Environmental Science & Technology. – 2022. – Vol. 56, № 3. – P. 1430–1442.

24. Jia X., Zhuang J., Ye H., Yang W., Chen X., Zhang W. Synergistic effects of biochar and organic amendments on the remediation of heavy metal contaminated soils: A review // Journal of Hazardous Materials. – 2021. – Vol. 416. – P. 125776.

25. Chen T., Jing W., Feng G., Ying L., YuHuan S., Yongming L. Biochar and bacteria inoculated biochar enhanced Cd and Cu immobilization and enzymatic activity in a polluted soil // Environmental International. – 2020. – Vol. 137. – P. 105576.

26. Yan Z., Liu X., Li R., Huang J., Zheng J., Zhang X. Effects of biochar application on greenhouse gas emissions from agricultural soils: A meta-analysis // Science of The Total Environment. – 2021. – Vol. 753. – P. 142020.

27. Liu Y., Chen Z., Wang L., Zhang H. Biochar's role in enhancing soil fertility and agroforestry sustainability: A review // Journal of Environmental Management. – 2022. – Vol. 310. – P. 114758.

28. Cao X., Ma L., Gao B., Harris W. Dairy-manure derived biochar effectively sorbs lead and atrazine // Environmental Science & Technology. – 2009. – Vol. 43(9). – P. 3285–3291.

29. Ryu C., Kim Y., Park J., Kim Y. S. Effect of biochar application on heavy metal mobility and microbial activity in contaminated soil // Chemosphere. – 2018. – Vol. 195. – P. 467–474.

30. Mukherjee A., Zimmerman A. R., Harris W. Surface chemistry variations among a series of laboratory-produced biochars // Geoderma. – 2011. – Vol. 163, № 3–4. – P. 247–255.

31. Rajapaksha A.U., Chen S.S., Tsang D.C.W., Zhang M., Vithanage M., Mandal S., Gao B., Bolan N.S., Ok Y.S. Engineered/designer biochar for contaminant removal/immobilization from soil and water: Potential and implication of biochar modification // Chemosphere. – 2016. – Vol. 148. – P. 276–291.

32. Johnson M. G., Wang X., Xu J., Liu Q., Chen Y. Biochar enhances heavy metal immobilization and microbial activity in contaminated sandy soils // Environmental Pollution. – 2021. – Vol. 273. – P. 116510.