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Surface Enthalpy of Boehmite

Published online by Cambridge University Press:  28 February 2024

Juraj Majzlan ,
Alexandra Navrotsky  and
William H. Casey
Juraj Majzlan*
Affiliation:
Thermochemistry Facility, Department of Geology, University of California at Davis, Davis, California 95616, USA
Alexandra Navrotsky
Affiliation:
Thermochemistry Facility, Department of Geology, University of California at Davis, Davis, California 95616, USA
William H. Casey
Affiliation:
Land, Water, and Air Resources, University of California at Davis, Davis, California 95616, USA
*
E-mail of corresponding author: [email protected]
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Abstract

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The persistence of many seemingly metastable mineral assemblages in sediments and soils is commonly attributed to their sluggish transformation to the stable-phase assemblage. Although undoubtedly kinetics plays a major role, this study shows that thermodynamic factors, particularly surface energy, significantly influence the free energy. Enthalpies of formation of boehmite samples with variable surface area were derived using high-temperature oxide-melt calorimetry. The average surface enthalpy for all faces terminating boehmite particles was calculated at +0.52 ± 0.12 J/m2. This value represents the surface enthalpy for surfaces exposed to vacuum assuming that H2O adsorbed on the surface of boehmite is loosely bound. These results show that the enthalpy of formation of boehmite may vary by ≤8 kJ/mol as a function of particle size. An overview of published values of surface energies of gibbsite, γ-Al2O3, corundum, and the results here indicates that the hydrated phases (boehmite, gibbsite) have lower surface energies than the anhydrous phases (corundum, γ-Al2O3). Lower surface energies allow the hydrated phases to maintain high surface area, i.e., small particle size. Similar surface energies of boehmite and gibbsite suggest kinetic control favoring the crystallization of boehmite or gibbsite from aqueous solution. The enthalpy of formation of bulk boehmite from the elements was calculated at −994.0 ±1.1 kJ/mol. Combining this result with the data in existing thermodynamic databases, we confirm that bulk boehmite is metastable with respect to bulk diaspore at ambient conditions.

Keywords

BoehmiteEnthalpy of FormationSurface Enthalpy
Type
Research Article
Information
Clays and Clay Minerals , Volume 48 , Issue 6 , December 2000 , pp. 699 - 707
Copyright
Copyright © 2000, The Clay Minerals Society

References

Anovitz, L.M. Allard, L.F. Porter, W.D. Coffey, D.W. Benezeth, P. Palmer, D.A. and Wesolowski, D.J., (1999) Microstructural characterization of water-rich boehmite (AlO(OH)): TEM correlation of apparently divergent XRD and TGA results Microscopy and Microanalysis: Proceedings of Microscopy and Microanalysis’ 99, Volume 5, Supplement 2 540–541.CrossRefGoogle Scholar
Anovitz, L.M. Perkins, D. and Essene, E.J., (1991) Metastability in near-surface rocks of minerals in the system Al, Or SiO2-H2O Clays and Clay Minerals 39 225–233 10.1346/CCMN.1991.0390301.CrossRefGoogle Scholar
Apps, J.A. Neil, J.M. and Jun, C.-H., (1989) Thermochemical Properties of Gibbsite, Bayerite, Boehmite, Diaspore, and the Aluminate Ion Between 0 and 350°C Washington, D.C. U.S. Nuclear Regulatory Commission 10.2172/6481805.CrossRefGoogle Scholar
Baker, B.R. and Pearson, R.M., (1974) Water content of pseudoboehmite: A new model for its structure Journal of Catalysis 33 265–278 10.1016/0021-9517(74)90270-X.CrossRefGoogle Scholar
Bardossy, G. and Aleva, G.J.J., (1990) Lateritic bauxites Developments in Economic Geology, Volume 27 .Google Scholar
Bellotto, M. Rebours, B. and Euzen, P., (1998) Mechanism of pseudo-boehmite dehydration: Influence of reagent structure and reaction kinetics on the transformation sequence Materials Science Forum Volumes 278 572–577 10.4028/www.scientific.net/MSF.278-281.572.CrossRefGoogle Scholar
Blonski, S. and Garofalini, S.H., (1993) Molecular dynamics simulation of a-alumina and y alumina surfaces Surface Science 295 263–274 10.1016/0039-6028(93)90202-U.CrossRefGoogle Scholar
Bloom, P.R. and Weaver, R.M., (1982) Effect of removal of reactive surface material on the solubility of synthetic gibbsites Clays and Clay Minerals 30 281–286 10.1346/CCMN.1982.0300405.CrossRefGoogle Scholar
Bradley, S.M. Kydd, R.A. and Howe, R.F., (1993) The structure of Al-gels formed through base hydrolysis of Al3+ aqueous solutions Journal of Colloid Interface Science 159 405–412 10.1006/jcis.1993.1340.CrossRefGoogle Scholar
Bradley, S.M. and Hanna, J.V., (1994) Al and 23Na MAS NMR and powder X-ray diffraction studies of sodium aluminate spéciation and the mechanistics of aluminum hydroxide precipitation upon acid hydrolysis Journal of the American Chemical Society 116 7771–7783 10.1021/ja00096a038.CrossRefGoogle Scholar
Buol, S.W. Hole, F.D. and McCracken, R.J., (1989) Soil Genesis and Classification. Iowa State University Press .Google Scholar
Brunauer, S. Emmett, P.H. and Teller, E., (1938) Adsorption of gases in multimolecular layers Journal of the American Chemical Society 60 309–319 10.1021/ja01269a023.CrossRefGoogle Scholar
Causa, M. Dovesi, R. Pisani, C. and Roetti, C., (1989) Ab initio characterization of the (0001) and (1010) crystal faces of a-alumina Surface Science 215 259–271 10.1016/0039-6028(89)90713-9.CrossRefGoogle Scholar
Chesworth, W., (1972) The stability of gibbsite and boehmite at the surface of the Earth Clays and Clay Minerals 20 369–374 10.1346/CCMN.1972.0200604.CrossRefGoogle Scholar
Dyer, C. Hendra, P.J. Forsling, W. and Ranheimer, M., (1993) Surface hydration of aqueous γ-Al2O3, studied by Fourier transform Raman and infrared spectroscopy-I. Initial results Spectrochimica Acta 49A 691–705 10.1016/0584-8539(93)80092-O.CrossRefGoogle Scholar
Efron, B. and Tibshirani, R.J., (1993) An Introduction to the Bootstrap. Chapman and Hall 10.1007/978-1-4899-4541-9.CrossRefGoogle Scholar
Fleming, S. Rohl, A. Lee, M.-Y. Gale, J. and Parkinson, G., (2000) Atomistic modeling of gibbsite: Surface structure and morphology Journal of Crystal Growth 209 159–166 10.1016/S0022-0248(99)00479-0.CrossRefGoogle Scholar
Fu, G. Lazar, L.F. and Bain, A.D., (1991) Aging processes of alumina sol-gels: Characterization of new aluminum polycations by 27A1 spectroscopy Chemistry of Materials 3 602–610 10.1021/cm00016a009.CrossRefGoogle Scholar
Gregg, S.J. and Sing, K.S.W., (1982) Adsorption, Surface Area and Porosity .Google Scholar
Gribb, A.A. and Banfield, J.F., (1997) Particle size effects on transformation kinetics and phase stability in monocrystalline TiO2 American Mineralogist 82 717–728 10.2138/am-1997-7-809.CrossRefGoogle Scholar
Haas, K.C. Schneider, W.F. Curioni, A. and Andreoni, W., (1998) The chemistry of water on alumina surfaces: Reaction dynamics from first principles Science 282 265–268 10.1126/science.282.5387.265.CrossRefGoogle Scholar
Hemingway, B.S. Robie, R.A. and Apps, J.A., (1991) Revised values for the thermodynamic properties of boehmite, AlO(OH), and related species and phases in the system Al-H-O American Mineralogist 76 445–457.Google Scholar
Langel, W. and Parrinello, M., (1995) Ab initio molecular dynamics of H2O adsorbed on solid MgO Journal of Chemical Physics 103 3240–3252 10.1063/1.470256.CrossRefGoogle Scholar
Lindan, P.J.D. Harrison, N.M. Holender, J.M. and Gillan, M.J., (1996) First-principles molecular dynamics simulation of water dissociation on TiO2 (110) Chemical Physics Letters 261 246–252 10.1016/0009-2614(96)00934-7.CrossRefGoogle Scholar
Mackrodt, W.C. Davey, R.J. and Black, S.N., (1987) The morphology of α-Al2O3, and α-Fe2O3: The importance of surface relaxation Journal of Crystal Growth 80 441–446 10.1016/0022-0248(87)90093-5.CrossRefGoogle Scholar
McHale, J.M. Auroux, A. Perrotta, A.J. and Navrotsky, A., (1997) Surface energies and thermodynamic phase stability in nanocrystalline aluminas Science 277 788–791 10.1126/science.277.5327.788.CrossRefGoogle Scholar
McHale, J.M. Navrotsky, A. and Perrotta, A.J., (1997) Effects of increased surface area and chemisorbed H2O on the relative stability of nanocrystalline γ-Al2O3 and α-Al2O3 The Journal of Physical Chemistry B 101 603–613 10.1021/jp9627584.CrossRefGoogle Scholar
McHardy, W.J. and Thomson, A.P., (1971) Conditions for the formation of bayerite and gibbsite Mineralogical Magazine 38 358–368 10.1180/minmag.1971.038.295.11.CrossRefGoogle Scholar
May, H.M. Helmke, P.A. and Jackson, M.L., (1979) Gibbsite solubility and thermodynamic properties of hydroxy-aluminum ions in aqueous solutions at 25°C Geochimica et Cosmochimica Acta 43 861–868 10.1016/0016-7037(79)90224-2.CrossRefGoogle Scholar
National Bureau of Standards Certificate: Standard Reference Material 720, (1982) Synthetic sapphire (α-Al2O3). Washington, D.C., April 1982.Google Scholar
Navrotsky, A., (1997) Progress and new directions in high temperature calorimetry revisited Physics and Chemistry of Minerals 24 222–241 10.1007/s002690050035.CrossRefGoogle Scholar
Navrotsky, A. Rapp, R.P. Smelik, E. Burnley, P. Circone, S. Liang, C. and Kunal, B., (1994) The behavior of H2O and CO2 in high-temperature lead borate solution calorimetry of volatile-bearing phases American Mineralogist 79 1099–1109.Google Scholar
Packter, A., (1979) Studies on recrystallized aluminium trihydroxide precipitates: The energetics of dissolution by sodium hydroxide solutions Colloid and Polymer Science 257 977–980 10.1007/BF01520724.CrossRefGoogle Scholar
Penn, R.L. Banfield, J.F. and Kerrick, D.M., (1999) TEM investigation of Lewiston, Idaho, fibrolite: Microstructure and grain boundary energetics American Mineralogist 84 152–159 10.2138/am-1999-1-217.CrossRefGoogle Scholar
Peryea, F.J. and Kittrick, J.A., (1988) Relative solubility of corundum, gibbsite, boehmite, and diaspore at standard state conditions Clays and Clay Minerals 36 391–396 10.1346/CCMN.1988.0360502.CrossRefGoogle Scholar
Robie, R.A. and Hemingway, B.S., (1995) Thermodynamic Properties of Minerals and Related Substances at 298.15 K and 1 bar (105 pascals) and at Higher Temperatures Washington, D.C. U.S. Geological Survey Bulletin 2131.Google Scholar
Robie, R.A. Hemingway, B.S. and Fisher, J.R., (1978) Thermodynamic Properties of Minerals and Related Substances at 298.15 K and 1 bar (HP pascals) and at Higher Temperatures Washington, D.C. U.S. Geological Survey Bulletin 1452.Google Scholar
Russell, A.S. Edwards, J.D. and Taylor, C.S., (1955) Solubility of hydrated aluminas in NaOH solutions Journal of Metals 203 1123–1128.Google Scholar
Seichter, W. Mögel, H.-J. Brand, P. and Saleh, D., (1998) Crystal structure and formation of the aluminum hydroxide chloride [All3(OH)24)(H2O)24]Cl15·13H2O European Journal of Inorganic Chemistry 1998 795–797 10.1002/(SICI)1099-0682(199806)1998:6<795::AID-EJIC795>3.0.CO;2-A.3.0.CO;2-A>CrossRefGoogle Scholar
Smith, R.W. and Hem, J.D., (1972) Effect of Aging on Aluminum Hydroxide Complexes in Dilute Aqueous Solutions Washington, D.C. Geological Survey Water-Supply Paper 1827-D.Google Scholar
Tasker, P.W. and Kingery, W.D., (1984) Surfaces of magnesia and alumina Structure and Properties of MgO and Al2O3 Ceramics, Advances in Ceramics, Volume 10 176–189.Google Scholar
Tettenhorst, R.T. and Hofmann, D.A., (1980) Crystal chemistry of boehmite Clays and Clay Minerals 28 373–380 10.1346/CCMN.1980.0280507.CrossRefGoogle Scholar
Tosi, M.P., (1964) Cohesion of ionic solids in the Bom model Solid State Physics 16 1–120 10.1016/S0081-1947(08)60515-9.CrossRefGoogle Scholar
Tsukada, T. Segawa, H. Yasumori, A. and Okada, K., (1999) Crystallinity of boehmite and its effect on the phase transition temperature of alumina Journal of Materials Chemistry 9 549–553 10.1039/a806728g.CrossRefGoogle Scholar
Wesolowski, D.J. and Palmer, D.A., (1994) Aluminum spéciation and equilibria in aqueous solution: V. Gibbsite solubility at 50°C and pH 3–9 in 0.1 molal NaCl solutions (a general model for aluminum spéciation; analytical methods) Geochimica et Cosmochimica Acta 58 2947–2969 10.1016/0016-7037(94)90171-6.CrossRefGoogle Scholar