TY - JOUR

T1 - Synthesis of a Sulfate Enclathrated Zeolite with Intermediate Framework Structure between Sodalite and Cancrinite

AU - Buhl, Josef Christian

PY - 2017/7/17

Y1 - 2017/7/17

N2 - A sulfate enclathrated microporous zeolite of composition Na7.4[SiAlO4]6(SO4)0.7(H2O)4.8 with intermediate framework structure (INT) between the well known zeolites sodalite (SOD) and cancrinite (CAN) can be prepared by the autothermal synthesis, a method first demonstrated in reference. The product (abbreviated as “SO4-INT”) was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX-analysis), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TG). SO4-INT was found to crystallize as spheres with 1–6 μm in diameter with a rough surface. Sometimes the spheres are agglutinated to each other by a few amount of amorphous material within the sample. The thermal behavior of the new phase was further studied. At elevated temperature (1000 °C) a transformation of SO4-INT into a large amount of nosean was observed beside some parts of nepheline, formed by crystallization of the amorphous byproduct. The nosean phase was found to be stable up to 1250 °C, before the onset of a total destruction by melting during further heating. Finally a re-crystallization of the melt during cooling yielded carnegieite as the final product (low form at room temperature). This unusual thermal behavior of SO4-INT is discussed in terms of structural interactions of the sulfate guests inside the aluminosilicate host-framework and in comparison with literature data of the intermediate phases CO3-INT, as well as NO3-INT.

AB - A sulfate enclathrated microporous zeolite of composition Na7.4[SiAlO4]6(SO4)0.7(H2O)4.8 with intermediate framework structure (INT) between the well known zeolites sodalite (SOD) and cancrinite (CAN) can be prepared by the autothermal synthesis, a method first demonstrated in reference. The product (abbreviated as “SO4-INT”) was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX-analysis), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TG). SO4-INT was found to crystallize as spheres with 1–6 μm in diameter with a rough surface. Sometimes the spheres are agglutinated to each other by a few amount of amorphous material within the sample. The thermal behavior of the new phase was further studied. At elevated temperature (1000 °C) a transformation of SO4-INT into a large amount of nosean was observed beside some parts of nepheline, formed by crystallization of the amorphous byproduct. The nosean phase was found to be stable up to 1250 °C, before the onset of a total destruction by melting during further heating. Finally a re-crystallization of the melt during cooling yielded carnegieite as the final product (low form at room temperature). This unusual thermal behavior of SO4-INT is discussed in terms of structural interactions of the sulfate guests inside the aluminosilicate host-framework and in comparison with literature data of the intermediate phases CO3-INT, as well as NO3-INT.

KW - Microporous solids

KW - Structural intermediates of SOD and CAN

KW - Sulfate enclathrated zeolites

KW - Thermal stability

KW - Zeolites

UR - http://www.scopus.com/inward/record.url?scp=85024487333&partnerID=8YFLogxK

U2 - 10.1002/zaac.201700101

DO - 10.1002/zaac.201700101

M3 - Article

AN - SCOPUS:85024487333

VL - 643

SP - 1030

EP - 1036

JO - Zeitschrift fur Anorganische und Allgemeine Chemie

JF - Zeitschrift fur Anorganische und Allgemeine Chemie

SN - 0044-2313

IS - 15

ER -