Heavy metals passivation driven by the interaction of organic fractions and functional bacteria during biochar/montmorillonite-amended composting

• Published in: Bioresource technology 2021-06, Vol.329, p.124923-124923, Article 124923
• Main Authors: Song, Caihong, Zhao, Yue, Pan, Delong, Wang, Shenghui, Wu, Di, Wang, Liqin, Hao, Jingkun, Wei, Zimin
• Format: Article
• Language: English
• Subjects: Bacteria; Bentonite; Biochar; Charcoal; Composting; Driving factor; Heavy metals bioavailability; Metals, Heavy - analysis; Montmorillonite; Soil
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2021.124923

[Display omitted] •Biochar/montmorillonite amended composting was conducted to deactivate HM.•Organic constituents exhibited indivisible relations with Cu/Zn speciation.•The diversity of Cu resistant/actor and Zn actor bacteria increased.•Critical pathway of mitigating Cu/Zn bioavailability was revealed.•Interaction of bacteria and organic components was the most key driving factor. The aim of this study was to identify critical driving factors and pathways of mitigating heavy metals (HM) bioavailability during biochar/montmorillonite-amended composting: emphasize on the interaction effect between organic constituents and functional bacteria. Organic components, such as humus (HS), humic (HA) and fulvic acid (FA) and dissolved organic carbon (DOC), exhibited indivisible links with Cu and Zn speciation, which confirmed their vital roles on deactivating Cu and Zn. Network analysis indicated that biochar/montmorillonite obviously increased the diversity of Cu resistant/actor and Zn actor bacteria, which aided in HM passivation. Although multiple pathways were involved in regulating Cu/Zn passivation, the interaction of bacteria and organic constituents was the most critical driving factor. Given that, promoting potential HM resistant/actor bacteria utilizing and transforming low-humification organic fractions coupling with elevating high-humification constituents were the optimal pathway. This study is helpful to practical application of biochar/montmorillonite to inactivate HM for industrial composting.