乙二胺四乙酸
化学
非闪锌矿
粘土矿物
铀
蒙脱石
配体(生物化学)
环境修复
无机化学
核化学
环境化学
螯合作用
污染
矿物学
有机化学
生态学
生物化学
材料科学
受体
冶金
生物
作者
Runjie Li,Limin Zhang,Yu Chen,Qingyin Xia,Dong Liu,Ying Huang,Hailiang Dong
标识
DOI:10.1021/acs.est.3c07385
摘要
Bioreduction of soluble U(VI) to sparingly soluble U(IV) is proposed as an effective approach to remediating uranium contamination. However, the stability of biogenic U(IV) in natural environments remains unclear. We conducted U(IV) reoxidation experiments following U(VI) bioreduction in the presence of ubiquitous clay minerals and organic ligands. Bioreduced Fe-rich nontronite (rNAu-2) and Fe-poor montmorillonite (rSWy-2) enhanced U(IV) oxidation through shuttling electrons between oxygen and U(IV). Ethylenediaminetetraacetic acid (EDTA), citrate, and siderophore desferrioxamine B (DFOB) promoted U(IV) oxidation via complexation with U(IV). In the presence of both rNAu-2 and EDTA, the rate of U(IV) oxidation was between those in the presence of rNAu-2 and EDTA, due to a clay/ligand-induced change of U(IV) speciation. However, the rate of U(IV) oxidation in other combinations of reduced clay and ligands was higher than their individual ones because both promoted U(IV) oxidation. Unexpectedly, the copresence of rNAu-2/rSWy-2 and DFOB inhibited U(IV) oxidation, possibly due to (1) blockage of the electron transport pathway by DFOB, (2) inability of DFOB-complexed Fe(III) to oxidize U(IV), and (3) stability of the U(IV)-DFOB complex in the clay interlayers. These findings provide novel insights into the stability of U(IV) in the environment and have important implications for the remediation of uranium contamination.
科研通智能强力驱动
Strongly Powered by AbleSci AI