Enhance U(VI) reduction on natural pyrite surfaces by gamma irradiation

Kang, Mingliang; Kang, Yixiao; Jin, Wujian; She, Jingye; Qin, Danwen; Wu, Hanyu; Weng, Hanqin; Chen, Chao; Li, Jiuqiang

doi:10.1016/j.cej.2024.151473

Cited by 3 publications

(1 citation statement)

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“…This process enhances the presence of F in the stable FAP phase (Figure b) and notably releases P into solution (Figure b). Previous studies have extensively discussed the nucleation and phase transformation of Fe (hydr)oxides, MnO x , UO x , and others on heterogeneous mineral surfaces, − emphasizing irreversible electron transfer leading to homogeneous oxidation . Typically, anionic species facilitate mineralization through bridging coordination at active sites on heterogeneous interfaces, similar to the immobilization of arsenate and phosphate, where limestone and iron oxide act as bridges. , This parallels the bridging role observed for Ca sites in our study.…”

Section: Discussionsupporting

confidence: 82%

In Situ Evolution of Ionic Sites at Clay Mineral Interfaces Facilitates Fluoride and Phosphorus Mineralization

Zhang,

Zhu,

Niu

et al. 2024

Environ. Sci. Technol.

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Soil minerals influence the biogeochemical cycles of fluoride (F) and phosphorus (P), impacting soil quality and bioavailability to plants. However, the cooperative mechanisms of soil minerals in governing F and P in the soil environment remain a grand challenge. Here, we reveal the essential role of a typical soil mineral, montmorillonite (Mt), in the cycling and fate of F and P. The results show that the enrichment of metal sites on the Mt surface promotes the mineralization of F to the fluorapatite (FAP) phase, thereby remaining stable in the environment, simultaneously promoting P release. This differential behavior leads to a reduction in the level of F pollution and an enhancement of P availability. Moreover, solid-state NMR and HRTEM observations confirm the existence of metastable F−Ca−F intermediates, emphasizing the pivotal role of Mt surface sites in regulating crystallization pathways and crystal growth of FAP. Furthermore, the in situ atomic force microscopy and theoretical calculations reveal molecular fractionation mechanisms and adsorption processes. It is observed that a competitive relationship exists between F and P at the Mt interface, highlighting the thermodynamically advantageous pathway of forming metastable intermediates, thereby governing the activity of F and P in the soil environment at a molecular level. This work paves the way to reveal the important role of clay minerals as a mineralization matrix for soil quality management and offers new strategies for modulating F and P dynamics in soil ecosystems.

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