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Formation of crystalline Zn-Al layered double hydroxide precipitates on γ-alumina: the role of mineral dissolution.
Environ Sci Technol. 2012 Nov 06; 46(21):11670-7.ES

Abstract

To better understand the sequestration of toxic metals such as nickel (Ni), zinc (Zn), and cobalt (Co) as layered double hydroxide (LDH) phases in soils, we systematically examined the presence of Al and the role of mineral dissolution during Zn sorption/precipitation on γ-Al(2)O(3) (γ-alumina) at pH 7.5 using extended X-ray absorption fine structure spectroscopy (EXAFS), high-resolution transmission electron microscopy (HR-TEM), synchrotron-radiation powder X-ray diffraction (SR-XRD), and (27)Al solid-state NMR. The EXAFS analysis indicates the formation of Zn-Al LDH precipitates at Zn concentration ≥0.4 mM, and both HR-TEM and SR-XRD reveal that these precipitates are crystalline. These precipitates yield a small shoulder at δ(Al-27) = +12.5 ppm in the (27)Al solid-state NMR spectra, consistent with the mixed octahedral Al/Zn chemical environment in typical Zn-Al LDHs. The NMR analysis provides direct evidence for the existence of Al in the precipitates and the migration from the dissolution of γ-alumina substrate. To further address this issue, we compared the Zn sorption mechanism on a series of Al (hydr)oxides with similar chemical composition but differing dissolubility using EXAFS and TEM. These results suggest that, under the same experimental conditions, Zn-Al LDH precipitates formed on γ-alumina and corundum but not on less soluble minerals such as bayerite, boehmite, and gibbsite, which point outs that substrate mineral surface dissolution plays an important role in the formation of Zn-Al LDH precipitates.

Authors+Show Affiliations

Environmental Soil Chemistry Group, Delaware Environmental Institute and Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19717, USA. weili@udel.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

23043294

Citation

Li, Wei, et al. "Formation of Crystalline Zn-Al Layered Double Hydroxide Precipitates On Γ-alumina: the Role of Mineral Dissolution." Environmental Science & Technology, vol. 46, no. 21, 2012, pp. 11670-7.
Li W, Livi KJ, Xu W, et al. Formation of crystalline Zn-Al layered double hydroxide precipitates on γ-alumina: the role of mineral dissolution. Environ Sci Technol. 2012;46(21):11670-7.
Li, W., Livi, K. J., Xu, W., Siebecker, M. G., Wang, Y., Phillips, B. L., & Sparks, D. L. (2012). Formation of crystalline Zn-Al layered double hydroxide precipitates on γ-alumina: the role of mineral dissolution. Environmental Science & Technology, 46(21), 11670-7. https://doi.org/10.1021/es3018094
Li W, et al. Formation of Crystalline Zn-Al Layered Double Hydroxide Precipitates On Γ-alumina: the Role of Mineral Dissolution. Environ Sci Technol. 2012 Nov 6;46(21):11670-7. PubMed PMID: 23043294.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Formation of crystalline Zn-Al layered double hydroxide precipitates on γ-alumina: the role of mineral dissolution. AU - Li,Wei, AU - Livi,Kenneth J T, AU - Xu,Wenqian, AU - Siebecker,Matthew G, AU - Wang,Yujun, AU - Phillips,Brian L, AU - Sparks,Donald L, Y1 - 2012/10/25/ PY - 2012/10/10/entrez PY - 2012/10/10/pubmed PY - 2013/4/20/medline SP - 11670 EP - 7 JF - Environmental science & technology JO - Environ Sci Technol VL - 46 IS - 21 N2 - To better understand the sequestration of toxic metals such as nickel (Ni), zinc (Zn), and cobalt (Co) as layered double hydroxide (LDH) phases in soils, we systematically examined the presence of Al and the role of mineral dissolution during Zn sorption/precipitation on γ-Al(2)O(3) (γ-alumina) at pH 7.5 using extended X-ray absorption fine structure spectroscopy (EXAFS), high-resolution transmission electron microscopy (HR-TEM), synchrotron-radiation powder X-ray diffraction (SR-XRD), and (27)Al solid-state NMR. The EXAFS analysis indicates the formation of Zn-Al LDH precipitates at Zn concentration ≥0.4 mM, and both HR-TEM and SR-XRD reveal that these precipitates are crystalline. These precipitates yield a small shoulder at δ(Al-27) = +12.5 ppm in the (27)Al solid-state NMR spectra, consistent with the mixed octahedral Al/Zn chemical environment in typical Zn-Al LDHs. The NMR analysis provides direct evidence for the existence of Al in the precipitates and the migration from the dissolution of γ-alumina substrate. To further address this issue, we compared the Zn sorption mechanism on a series of Al (hydr)oxides with similar chemical composition but differing dissolubility using EXAFS and TEM. These results suggest that, under the same experimental conditions, Zn-Al LDH precipitates formed on γ-alumina and corundum but not on less soluble minerals such as bayerite, boehmite, and gibbsite, which point outs that substrate mineral surface dissolution plays an important role in the formation of Zn-Al LDH precipitates. SN - 1520-5851 UR - https://www.unboundmedicine.com/medline/citation/23043294/Formation_of_crystalline_Zn_Al_layered_double_hydroxide_precipitates_on_γ_alumina:_the_role_of_mineral_dissolution_ L2 - https://doi.org/10.1021/es3018094 DB - PRIME DP - Unbound Medicine ER -