A FAU-X-rich porous monolith has been obtained by means of an unconventional two-stage method consisting of the production of a foamed geopolymeric precursor and its subsequent conversion by means of a hydrothermal method. The influence of the conversion process parameters, such as NaOH concentration (0.1–2 M), treatment temperature (40–80 °C) and time (24–72 h) on the FAU-X crystallization was studied. Collected data revealed that the highest yield in terms of zeolite content and FAU-X/LTA ratio was obtained performing the hydrothermal treatment with a 0.5 M NaOH solution at 60 °C. The crystallization kinetics of FAU-X inside the geopolymer precursor was investigated by means of Synchrotron Radiation X-Ray Diffraction Quantitative Phase Analysis (SR-XRD-QPA). Results showed that the crystallization starts after an induction time of about 3 days, and the weight percentage of the zeolite in the sample raises up to about 78% after 20 days of treatment. The highest yield in terms of zeolite content, about 80% of FAU-X and 6% of LTA, was reached at 20 days. Finally, Scanning Electron Microscopy (SEM) analysis showed the presence of well-defined octahedral crystals either on the pore surface or in the bulk of the sample starting from 3 days of hydrothermal treatment.
From geopolymers to zeolites: Synthesis and characterization of foamed FAU-X monoliths / Campanile, Assunta; Liguori, Barbara; Ferone, Claudio; Caputo, Domenico; Gigli, Lara; Aprea, Paolo. - In: MICROPOROUS AND MESOPOROUS MATERIALS. - ISSN 1387-1811. - 349:(2023), p. 112426. [10.1016/j.micromeso.2022.112426]
From geopolymers to zeolites: Synthesis and characterization of foamed FAU-X monoliths
Assunta Campanile;Barbara Liguori;Domenico Caputo;Paolo Aprea
2023
Abstract
A FAU-X-rich porous monolith has been obtained by means of an unconventional two-stage method consisting of the production of a foamed geopolymeric precursor and its subsequent conversion by means of a hydrothermal method. The influence of the conversion process parameters, such as NaOH concentration (0.1–2 M), treatment temperature (40–80 °C) and time (24–72 h) on the FAU-X crystallization was studied. Collected data revealed that the highest yield in terms of zeolite content and FAU-X/LTA ratio was obtained performing the hydrothermal treatment with a 0.5 M NaOH solution at 60 °C. The crystallization kinetics of FAU-X inside the geopolymer precursor was investigated by means of Synchrotron Radiation X-Ray Diffraction Quantitative Phase Analysis (SR-XRD-QPA). Results showed that the crystallization starts after an induction time of about 3 days, and the weight percentage of the zeolite in the sample raises up to about 78% after 20 days of treatment. The highest yield in terms of zeolite content, about 80% of FAU-X and 6% of LTA, was reached at 20 days. Finally, Scanning Electron Microscopy (SEM) analysis showed the presence of well-defined octahedral crystals either on the pore surface or in the bulk of the sample starting from 3 days of hydrothermal treatment.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.