Surface Precipitation of Co(II)(aq) on Al2O3

Towle, Steven N.; Bargar, John R.; Brown, Gordon E.; Parks, George S.

doi:10.1006/jcis.1996.4539

Cited by 215 publications

(208 citation statements)

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“…Several laboratory studies of metal ion partitioning identify the precipitation of mixed metal hydroxides known as hydrotalcites as a significant uptake route for metal ions (d'Espinose de la Caillerie et al, 1995;Scheidegger et al, 1997;Towle et al, 1997;Thompson et al, 1999). Although precipitation was shown to (001) showing hydroxide layers (top, middle, and bottom) interlayered with O atoms from hydration water.…”

Section: Introductionmentioning

confidence: 99%

Ambient-Temperature Synthesis, Evolution, and Characterization of Cobalt-Aluminum Hydrotalcite-Like Solids

Thompson

1999

Clays and clay miner.

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Abstract--Double hydroxide solids precipitated homogeneously from three laboratory-synthesized aqueous solutions that simulated mildly contaminated surface or groundwater. Over a limited pH range, precipitates formed rapidly from dissolved ions, and more slowly by incorporating ions dissolving from other solids, including highly soluble aluminous solids. The precipitates were characterized by size and shape via transmission electron microscopy (TEM), by composition via inductively coupled plasma-mass spectrometry (ICP-MS) of mother solutions and analytical electron microscopy (AEM) of precipitates, and by structure via powder X-ray diffraction (XRD), TEM, and extended X-ray absorption fine structure (EXAFS) spectroscopy. They were identified as nanocrystalline cobalt hydrotalcite (CoHT) of the form [Co(II)1 xAl(III)x(OH)~]x+(A " ~/n).mH20, with x = 0.17-0.25, A = CO32 , NO3-, or H3SiO 4 , n = anion charge and m undetermined. Complete solid solution may exist at the macroscopic level for the range of stoichiometries reported, but clustering of Co atoms within hydroxide layers indicates a degree of immiscibility at the molecular scale. Composition evolved toward the Co-rich endmember with time for at least one precipitate. The small layer charge in the x = 0.17 precipitate caused anionic interlayers to be incomplete, producing interstratification of hydrotalcite and brucite-like layers. Solubility products estimated from solution measurements for the observed final CoHT stoichiometries suggest that CoHT is less soluble than the inactive forms of Co(OH)2 and COCO3 near neutral pH. Low solubility and rapid formation suggest that CoHT solids may be important sinks for Co in contact with near neutral pH waters. Because hydrotalcite can incorporate a range of transition metals, precipitation of hydrotalcite may be similarly effective for removing other trace metals from natural waters.

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Section: Introductionmentioning

confidence: 99%

Ambient-Temperature Synthesis, Evolution, and Characterization of Cobalt-Aluminum Hydrotalcite-Like Solids

Thompson

1999

Clays and clay miner.

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“…More recently, LDHs have been shown to be important compounds in water oxidation catalysis 18 . Al-based LDHs occurring in soil environments have been identified for reactions with iron(II), cobalt, Ni and zinc 11,13,[19][20][21][22][23][24][25] .…”

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confidence: 99%

Real-time QEXAFS spectroscopy measures rapid precipitate formation at the mineral–water interface

Siebecker

Khalid

et al. 2014

Nat Commun

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Reactions at the mineral-water interface are central to numerous geochemical processes and have consequences at local, regional and global scales. They are also important in materials science research. Kinetics greatly influences mineral-water interface reactions; however, there are few kinetic data in real-time and at the molecular scale. Here we report real-time data illustrating the rapid formation of nickel aluminium-layered double hydroxide precipitates at the mineral-water interface in a flow environment in as little as 31-40 min. Layered double hydroxides have a variety of applications in environmental remediation and materials science. The real-time data shown here enhance our fundamental understanding of the kinetics of mineral-water interface processes, such as adsorption, dissolution and precipitation, by illustrating their rapid and simultaneous occurrence in a dynamic environment. Both precipitation and adsorption can occur on the same rapid timescale.

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“…Co(II) or Ni(II)) may lead to the surface precipitation of clay-type mixed neophases such as phyllosilicate [25][26][27] or hydrotalcite (layered double hydroxide). 28,29 because of the lack of reference compounds.…”

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confidence: 99%

EXAFS spectroscopy as a tool to probe metal–support interaction and surface molecular structures in oxide-supported catalysts: application to Al2O3-supported Ni(ii) complexes and ZrO2-supported tungstates

Carrier

Marceau

Carabineiro

et al. 2009

Phys. Chem. Chem. Phys.

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Surface Precipitation of Co(II)(aq) on Al2O3

Cited by 215 publications

References 16 publications

Ambient-Temperature Synthesis, Evolution, and Characterization of Cobalt-Aluminum Hydrotalcite-Like Solids

Ambient-Temperature Synthesis, Evolution, and Characterization of Cobalt-Aluminum Hydrotalcite-Like Solids

Real-time QEXAFS spectroscopy measures rapid precipitate formation at the mineral–water interface

EXAFS spectroscopy as a tool to probe metal–support interaction and surface molecular structures in oxide-supported catalysts: application to Al2O3-supported Ni(ii) complexes and ZrO2-supported tungstates

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