Unlocking the potential of surface modification with phosphate on ball milled zero-valent iron reactivity:Implications for radioactive metal ions removal.

Numerous investigations have illuminated the profound impact of phosphate on the adsorption of uranium, however, the effect of phosphate-mediated surface modification on the reactivity of zero-valent iron (ZVI) remained enigmatic. In this study, a phosphate-modified ZVI (P-ZVI _bm ) was prepared with a facile ball milling strategy, and compared with ZVI _bm , the U(VI) removal amount (435.2 mg/g) and efficiency (3.52×10 ^-3 g·mg ^-1 ·min ^-1 ) of P-ZVI _bm were disclosed nearly 2.0 and 54 times larger than those of ZVI _bm respectively. The identification of products revealed that the adsorption mechanism dominated the removal process for ZVI _bm , while the reactive modified layer strengthened both the adsorption pattern and reduction performance on P-ZVI _bm . DFT calculation result demonstrated that the binding configuration shifted from bidentate binuclear to multidentate configuration, further shortening the Fe-U atomic distance. More importantly, the electron transferred is more accessible through the surface phosphate layer, and selectively donated to U(VI), accounting for the elevated reduction performance of P-ZVI _bm . This investigation explicitly underscores the critical role of ZVI's surface microenvironment in the domain of radioactive metal ion mitigation and introduces a novel methodology to amplify the sequestration of U(VI) from aqueous environments.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yuhui Liu reports financial support was provided by National Natural Science Foundation of China.
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