Pedosphere 33(1): 23--33, 2023
ISSN 1002-0160/CN 32-1315/P
©2023 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Insight into modified biochars and their immobilizing effects on heavy metal(loid)s in contaminated soils: Mechanisms and influencing factors
Ehma Rose GUERET YADIBERET MENZEMBERE1,2, Yinhai HE1,2, Yingbo DONG1,2, Bing LI1,2, Chenjing LIU1,2, Hai LIN1,2, and Lengue SAMBIANI3
1 School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083(China)
2 Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing 100083(China)
3 University of International Business and Economics, Beijing 100029(China)
Corresponding Author:Ehma Rose GUERET YADIBERET MENZEMBERE
      Soil contamination by heavy metal(loid)s is a considerable environmental concern, and immobilization is a promising way to reduce toxicity. In recent years, modified/engineered biochars have gained enormous attention for their use in soil remediation, and various studies have reported notable results from their application and their ability to immobilize heavy metal(loid)s. In this review, a summary of publications on the utilization of modified biochars is presented to address the heavy metal(loid) threat in soils. Various modified/engineered biochars were described from the review of relevant publications. Modification causes great changes in biochar surface chemistry, such as increases in pore volume, surface functional groups, and metal binding sites, which can be observed through various analytical techniques, including Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and magnetism. Such analytical approaches elucidate immobilization mechanisms of adsorption, precipitation, surface complexation, and cation exchange between biochar and metal(loid) ions. In addition, the performance of biochar in remediating heavy metal(loid)s also leads to considerable improvements in soil conditions. Additionally, many factors that influence metal(loid) immobilization by biochar in soil, such as pH, redox potential, microorganisms, and climate regime, are highlighted. Finally, this paper emphasizes that using modified biochars as an immobilizing agent for remediation of heavy metal(loid)-polluted soils is promising and would be practicable if a comprehensive mechanism of their long-term stability in soil is well elucidated.
Key Words:  amendment,immobilization,pollutant,strategy,surface chemistry
Citation: Gueret Yadiberet Menzembere E R, He Y H, Dong Y B, Li B, Liu C J, Lin H, Sambiani L. 2023. Insight into modified biochars and their immobilizing effects on heavy metal(loid)s in contaminated soils: Mechanisms and influencing factors. Pedosphere. 33(1): 23-33.
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