TY - JOUR
T1 - Formation and hydration enthalpies of the hydrosodalite family of materials
AU - Moloy, Eric C.
AU - Liu, Qingyuan
AU - Navrotsky, Alexandra
N1 - Funding Information:
We thank May Nyman for advice about synthesis and Miaojun Wang for taking the SEM photographs. This work was supported by the US Department of Energy EMSP Program, grant DE-FG07-01ER63298.
PY - 2006/1/21
Y1 - 2006/1/21
N2 - The four end-member structures of the hydrosodalite family of materials (Na6+x(OH)x[Al6Si6O 24](H2O)N) are synthesized via hydrothermal techniques and characterized using X-ray diffraction, thermal analysis, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. High-temperature drop-solution calorimetry in molten 2PbO • B2O3 at 975 K is used to measure the formation and hydration enthalpies. We report the formation enthalpies, from both the oxides and the elements, for a total of eight samples, two for each end-member. The average formation enthalpy (from oxides) is -88.1 ± 1.0 kJ/mol-TO 2 for basic sodalite{ideally Na8(OH)2[Al 6Si6O24](H2O)4},-79.6 ± 1.2 kJ/mol-TO2 for hydroxysodalite{ideally Na 8(OH)2[Al6Si6O24]},-68.0 ± 1.1 kJ/mol-TO2,for hydrosodalite{ideally Na 6[Al6Si6O24](H2O) 8},and -54.9 ± 1.1 kJ/mol-TO2, for sodalite{ideally Na6[Al6Si6O24]}.The corresponding average hydration enthalpies are -76.7 ± 5.3 kJ/mol-H2O and -37.0 ± 2.4 kJ/mol-H2O for the Na8 and Na6 series, respectively.
AB - The four end-member structures of the hydrosodalite family of materials (Na6+x(OH)x[Al6Si6O 24](H2O)N) are synthesized via hydrothermal techniques and characterized using X-ray diffraction, thermal analysis, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. High-temperature drop-solution calorimetry in molten 2PbO • B2O3 at 975 K is used to measure the formation and hydration enthalpies. We report the formation enthalpies, from both the oxides and the elements, for a total of eight samples, two for each end-member. The average formation enthalpy (from oxides) is -88.1 ± 1.0 kJ/mol-TO 2 for basic sodalite{ideally Na8(OH)2[Al 6Si6O24](H2O)4},-79.6 ± 1.2 kJ/mol-TO2 for hydroxysodalite{ideally Na 8(OH)2[Al6Si6O24]},-68.0 ± 1.1 kJ/mol-TO2,for hydrosodalite{ideally Na 6[Al6Si6O24](H2O) 8},and -54.9 ± 1.1 kJ/mol-TO2, for sodalite{ideally Na6[Al6Si6O24]}.The corresponding average hydration enthalpies are -76.7 ± 5.3 kJ/mol-H2O and -37.0 ± 2.4 kJ/mol-H2O for the Na8 and Na6 series, respectively.
KW - Formation enthalpy
KW - Hydration enthalpy
KW - Hydrothermal synthesis
KW - Sodalite
KW - Zeolite
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U2 - 10.1016/j.micromeso.2005.09.020
DO - 10.1016/j.micromeso.2005.09.020
M3 - Article
AN - SCOPUS:29244466115
SN - 1387-1811
VL - 88
SP - 283
EP - 292
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
IS - 1-3
ER -