School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
SINTEF Industry, Department of Materials and Nanotechnology, Forskningsveien 1, 0373 Oslo, Norway.
J Hazard Mater. 2023 Jan 5;441:129833. doi: 10.1016/j.jhazmat.2022.129833. Epub 2022 Aug 24.
In this study, an integrated system of Fe and hydrogenotrophic microbes mediated by nitrate (nitrate-mediated bio-Fe, NMB-Fe) was established to remediate Cd(II)-contaminated sediment. Solid phase characterization confirmed that aqueous Cd(II) (Cd(II)) was successfully immobilized and enriched on iron surface due to promoted iron corrosion driven by hydrogenotrophic denitrification and subsequent greater biomineral production such as magnetite, lepidocrocite and green rust. Compared to a Cd(II) removal of 21.1% in overlying water of the nitrate-mediated Fe (NM-Fe) system, the NMB-Fe system obtained a much higher Cd(II) removal of 83.1% after 7 d remediation. The leaching test and sequential extraction results also showed that the leachability of Cd(II) decreased by 75.9% while the residual fraction of Cd(II) increased by 185.7% in comparison with untreated sediment. Besides, the Cd(II) removal raised with the increase of nitrate concentration and Fe dosage, further revealing the promotion effect of nitrate on Cd(II) removal by bio-Fe. This study highlighted the involvement of bio-denitrification in the remediation of Cd(II)-contaminated sediment by Fe and provided a new insight to enhance its reactivity and applicability for Cd(II) immobilization.
在这项研究中，建立了一个由硝酸盐介导的铁和氢营养微生物的综合系统（硝酸盐介导的生物铁，NMB-Fe），以修复镉（II）污染的沉积物。固相特征化证实，由于氢营养反硝化驱动的铁腐蚀得到促进，随后生物矿化产物（如磁铁矿、纤铁矿和绿锈）的产量增加，水相中 Cd(II)（Cd(II)）成功地固定和富集在铁表面。与硝酸盐介导的 Fe（NM-Fe）系统中上层水的 Cd(II)去除率为 21.1%相比，NMB-Fe 系统在 7 天修复后获得了更高的 Cd(II)去除率 83.1%。浸出试验和顺序提取结果还表明，与未处理的沉积物相比，Cd(II)的浸出率降低了 75.9%，而 Cd(II)的残留分数增加了 185.7%。此外，Cd(II)去除率随着硝酸盐浓度和 Fe 剂量的增加而提高，进一步揭示了硝酸盐对生物铁去除 Cd(II)的促进作用。本研究强调了生物反硝化在铁修复镉（II）污染沉积物中的作用，并为提高其反应性和适用性以固定 Cd(II)提供了新的见解。
