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Fraccionamiento de isótopos de antimonio dependiente de faceta durante Sb (V) Adsorción en hematita
Weiqing Zhou1,2,3, Jianwei Zhou1,2,3, Yanxin Wang1,2
1School of Environmental Studies, China University of Geosciences, Wuhan 430078, China.
Environmental science & technology
|February 11, 2026
Resumen
Las facetas de la hematita influyen en la adsorción de antimonio (Sb) y la fraccionamiento isotópico. La faceta (012) muestra una adsorción más fuerte que (001), con isótopos de Sb más ligeros que se enriquecen preferentemente en ambas superficies.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- Ciencias ambientales Ciencias ambientales.
- La mineralogía es la Mineralogía.
Sus antecedentes:
- La hematita es prevalente en el suelo y el agua, impactando el destino ambiental del antimonio (Sb) a través de la adsorción.
- Los roles específicos de las diferentes facetas de hematita en la fraccionamiento isotópico de Sb siguen siendo poco conocidos.
Objetivo del estudio:
- Para investigar los mecanismos de adsorción de Sb(V) en las facetas de hematita (001) y (012).
- Para dilucidar los mecanismos de fraccionamiento del isótopo Sb asociados con estos procesos de adsorción.
Principales métodos:
- Se llevaron a cabo experimentos de adsorción por lotes.
- Se empleó la espectroscopia de estructura fina de absorción de rayos X extendida (EXAFS).
- Se utilizaron cálculos de la teoría funcional de la densidad (DFT, por sus siglas en inglés).
Principales resultados:
- La faceta de hematita (012) exhibió una mayor capacidad de adsorción de Sb (V) que la faceta de hematita (001).
- La adsorción de Sb involucró complejos de intercambio de bordes en (001) y complejos de intercambio de bordes / esquinas coexistentes en (012).
- Los isótopos de Sb más ligeros se enriquecieron preferentemente en ambas facetas a través de la fraccionamiento de equilibrio, independientemente del pH y la concentración.
Conclusiones:
- La complejación de la capa de Sb-Fe más débil de la faceta (001) condujo a una mayor fraccionamiento isotópico de Sb (Δ123Sb = 14.11 ± 0.03 ‰) en comparación con la faceta (012) (Δ123Sb = 9.8 ± 0.02 ‰).
- Los hallazgos avanzan en la comprensión de la fraccionamiento del isótopo Sb en las superficies minerales.
- Proporciona información para predecir la adsorción de metales y la fraccionamiento de isótopos en los sistemas ambientales.
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