The effects of humic acids (HA) and fulvic acids (FA) on the fate of Cd in anaerobic environment upon microbial reduction of Cd-bearing ferrihydrite (Fh) with Geobacter metallireducens were investigated. The results showed that HA and FA could promote the reductive dissolution of Fh and the formation of vivianite. After incubation of 38 d, vivianite accounted for 47.19%, 59.22%, and 48.53% of total Fe in biological control batch (BCK), HA and FA batches (C/Fe molar ratio of 1.0), respectively, by Mössbauer spectroscopy analysis. In terms of Cd, HA and FA could promote the release of adsorbed Cd during the initial bioreduction process, but reassuringly, after 38 d the dissolved Cd with HA and FA addition batches were 0.58-0.91 and 0.99-1.08 times of the BCK, respectively. The proportions of residual Cd in HA batches were higher than FA and BCK batches, indicating that HA was better than FA in immobilizing Cd. This might be because the quinone groups in HA could act as electron shuttle. This study showed that HA facilitated the transformation of vivianite better than FA, and Cd can be stabilized by resorption or co-precipitation with vivianite, providing a theoretical support for the translocation of Cd in sediment-water interface.
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http://dx.doi.org/10.1016/j.jhazmat.2022.130655 | DOI Listing |
Environ Sci Technol
December 2024
Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, CHN, ETH Zürich, 8092 Zürich, Switzerland.
Coastal sediments are a key contributor to oceanic phosphorus (P) removal, impacting P bioavailability and primary productivity. Vivianite, an Fe(II)-phosphate mineral, can be a major P sink in nonsulfidic, reducing coastal sediments. Despite its importance, vivianite formation processes in sediments remain poorly understood.
View Article and Find Full Text PDFWater Res
January 2025
Key laboratory of the Three Gorges Reservoir Region's Eco-environments, Ministry of Education, Institute of Environment and Ecology, Chongqing University, 174 Shapingba Road, Chongqing, 400045, China.
Vivianite, a notable secondary mineral formed through dissimilatory iron reduction (DIR), demonstrates great potential in addressing both eutrophication and phosphorus deficiency. However, the presence of competition for electrons from the methanogenic pathway and the low rates of Fe(III) reduction limit the creation of vivianite. In this research, H was utilized as electron donor assisted by activated carbon (AC) to promote Fe(Ⅲ) reduction with FePO as electron acceptors.
View Article and Find Full Text PDFWater Res
January 2025
Tianjin Key Lab of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China. Electronic address:
Water Res
November 2024
School of Environmental Science and Engineering, Tianjin University, No. 135 Yaguan Road, Jinnan District, Tianjin, 300350, China. Electronic address:
The reducibility of iron oxides, depending on their properties, influences the kinetics of dissimilatory iron reduction (DIR) during vivianite recovery in sewage. This study elucidated the correlation between properties of iron oxides and kinetics of DIR during the long-term transformation into vivianite, mediated by Geobacter sulfurreducens PCA and sewage. The positive correlation between surface reactivity of iron oxides and reduction rate constant (k) influenced the terminal vivianite recovery efficiency.
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October 2024
Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address:
Iron minerals in nature are pivotal hosts for heavy metals, significantly influencing their geochemical cycling and eventual fate. It is generally accepted that, vivianite, a prevalent iron phosphate mineral in aquatic and terrestrial environments, exhibits a limited capacity for adsorbing cationic heavy metals. However, our study unveils a remarkable phenomenon that the synergistic interaction between sulfide (S) and vivianite triggers an unexpected sulfidation-reoxidation process, enhancing the immobilization of heavy metals such as cadmium (Cd), copper (Cu), and zinc (Zn).
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