AUTHOR=Wang Zhen , Chen Jinhui , Tan Jiaqi , Lu Zijing , Wang Xizhuo , Jianbo Li  

TITLE=The bio-immobilization of Pb(II) induced by the Chlorella–montmorillonite composite in the Ca(II) environment

JOURNAL=Frontiers in Environmental Science

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2022.983430

DOI=10.3389/fenvs.2022.983430

ISSN=2296-665X

ABSTRACT=<p>The clay–microbial consortium is ubiquitous in the soil near the mining area and plays an important role in the transport of heavy metals. In this study, <italic>Chlorella sorokiniana</italic> FK was separated from lead–zinc mine tailings. The montmorillonite–<italic>Chlorella sorokiniana</italic> FK system as a typical case was applied to study Pb(II) biomineralization in the presence of usually co-existent Ca(II) and further reduce the migration and transformation of Pb(II) in the Ca(II) environment. <italic>Chlorella sorokiniana</italic> FK showed good resistance to Pb(II), and the addition of montmorillonite provided a more stable pH environment, which is conducive to the stability of Pb(II)-bearing bio-minerals. Montmorillonite created a low-biotoxicity environment in the overall process, especially less Pb(II) bio-adsorption capacity of individual <italic>Chlorella</italic> to protect the process of mineralization effectively. Batch experiment results also demonstrated that montmorillonite as the formation site of bio-minerals results in dispersed minerals on the surface of <italic>Chlorella</italic> and <italic>Chlorella</italic>–MMT composite, which is beneficial to the survival of <italic>Chlorella</italic>. Moreover, Pb(II)-bearing phosphate minerals tended to form in the Ca(II) environment rather than without Ca(II). This study demonstrated the mechanism of Pb(II) immobilization induced by <italic>Chlorella</italic> in the Ca(II) environment, further presenting a green, sustainable, and effective strategy for Pb(II) bio-immobilization combining clay minerals and microorganisms.</p>