Bioleaching and immobilizing of copper and zinc using endophytes coupled with biochar-hydroxyapatite: Bipolar remediation for heavy metals contaminated mining soils. (February 2023)

• Record Type: Journal Article
• Authors: Feng, Weiran; Xiao, Xiao; Li, Junjie; Xiao, Qicheng; Ma, Li; Gao, Qifeng; Wan, Yuke; Huang, Yutian; Liu, Ting; Luo, Xubiao; Luo, Shenglian; Zeng, Guisheng; Yu, Kai
• Is Part Of: Chemosphere. Volume 315(2023)
• Publication Date: 2023-02
• Subjects: Endophytes -- Bioleaching -- Immobilization -- Bipolar remediation -- Heavy metal -- Mining; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.137730
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Copper and zinc are toxic heavy metals in soils that require development of feasible strategies for remediation of contaminated soils around the mine areas. In this study, the processing conditions and mechanisms of immobilization and bioleaching for remediation of highly contaminated soils with heavy metals are investigated. Soil remediation is carried out using a bioleaching-immobilization bipolar method. The results show that LSE03 bacteria provide efficient leaching result and immobilization on Cu 2+ and Zn 2+ . Among the bacterial metabolites, cis, cis -muconic acid and isovaleric acid play major roles in the bioleaching process. The bacterial extracellular polymeric substances are rich in a variety of organic acids that show a significant decrease in content after the adsorption process, indicating that all of these substances are involved in the binding of heavy metals. Characterization of the endophytes and immobilizing agents with FTIR, TEM-mapping, and XPS techniques reveal the ability of both bacteria and composites to adsorb Cu–Zn as well as the main functional groups of –OH, –COOH, –PO4 3–, and –NH. According to the heavy metals species analyses, competitive adsorption experiments, and bioleaching desorption experiments, it is planned to carry out the bipolar remediation of contaminated soil through immobilization followed by bioleaching process. After bipolar remediation processing, 97.923% and 96.387% of available Cu and Zn are respectively removed. Soils fertility significantly increases in all cases. Our study provides a green, practical, and environmentally friendly treatment method for soils contaminated with high concentrations of heavy metals. Graphical abstract: Image 1 Highlights: Studied remediation processing and mechanism of contaminated soils with heavy metals. Carried out soil remediation using a bioleaching-immobilization bipolar method. Endophytes LSE03 exhibited good performance in both bioleaching and immobilization. Achieved remediation of heavy metals contaminated mine soils by immobilization and bioleaching. Immobilization followed by bioleaching revealed best effect on remediation of contaminated soil.