These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Arsenate-reducing bacteria-mediated arsenic speciation changes and redistribution during mineral transformations in arsenate-associated goethite.
    Author: Cai X, Yin N, Wang P, Du H, Liu X, Cui Y.
    Journal: J Hazard Mater; 2020 Nov 05; 398():122886. PubMed ID: 32512445.
    Abstract:
    The fate of Fe(III)-(oxyhydr)oxides-bound As was generally regulated by dissimilatory As(V)-reduction. However, the impact of pH and bacterial conditions on the coupled processes of microbially-mediated As speciation changes and Fe-mineral transformation remains unclear. Our study therefore incubated As(V)-associated goethite with different As(V)-reducing bacteria at a range of pH. Results show that As reduction was most prominent at pH 7 as the bacterial growth was optimal. However, aqueous As concentration was the lowest (0.8-3.7 mg/L), due to rapid microbial Fe(II) formation at pH 7 triggered secondary mineralization and significant As-readsorption. Our study provides the first spectroscopic evidence for mineral-phase temporal evolution, and indicates in the presence of phosphate, vivianite will precipitate first and adsorb large amount of As(III) (40-44% of solid As). Thereafter, continuously increased Fe(II) may catalyze lepidocrocite and eventually magnetite formation, which further sequestrate aqueous As(III). Conversely, at pH 5 and 9, bacterial growth was inhibited, the corresponding lower microbially-derived Fe(II) concentrations caused no secondary minerals formation. Released As(III) was therefore largely remained in solution (6-9.7 mg/L). Our study demonstrates that As-bound Fe(III)-(oxyhydr)oxides could pose greater risks under acidic or alkaline conditions in biotic reactions. Additionally, bacterial species could strongly impact Fe-mineral transformation pathways and As solid-solution redistribution.
    [Abstract] [Full Text] [Related] [New Search]