Micro- and macroscopic observations of the nucleation process and crystal growth of nanosized Cs-pollucite in an organotemplate-free hydrosol

Eng-Poh Ng (1) , Aleid Ghadah Mohammad S (2) , Séverinne Rigolet (3) , T. Jean Daou (4) , Svetlana Mintova (5) , Tau Chuan Ling (6)

1 USM - Universiti Sains Malaysia
2 University of Hail
3 IS2M - Institut de Science des Matériaux de Mulhouse
4 LMPC - Laboratoire de Matériaux à Porosité Contrôlée
5 LCS - Laboratoire catalyse et spectrochimie
6 UM - University of Malaya = Universiti Malaya [Kuala Lumpur, Malaisie]

The nucleation and crystal growth of nanoscale cesium pollucite aluminosilicate zeolite (ANA topology) from an organotemplate-free precursor suspension are reported. By using a new and reactive synthesis recipe (5.5SiO2:1Al2O3:6Cs2O:140H2O), zeolite nanocrystals with higher Al content (Si/Al ratio = 2.12) are obtained within 120 min under mild condition (180 °C) which is much faster and safer as compared to those previously reported. The solid initially experiences amorphous phase reorganization before nucleation, crystallization and crystal growth take place. The resulting Cs-pollucite nanocrystals (average size 55 nm) display trapezohedron morphology. The nanocrystals are colloidally stabilized in water and they are very active in base-catalyzed cyanoethylation of dipropylamine reaction, giving 89.6% conversion at 180 °C within 50 min. In addition, high solid yield of nanocrystals (ca. 70%) is also achieved, thus offering a green pathway for synthesizing zeolite nanocrystals with high basicity in large scale.

Domaines: Chimie

Eng-Poh Ng, Aleid Ghadah Mohammad S, Séverinne Rigolet, T. Jean Daou, Svetlana Mintova, et al.. Micro- and macroscopic observations of the nucleation process and crystal growth of nanosized Cs-pollucite in an organotemplate-free hydrosol. New Journal of Chemistry, 2019, 43 (44), pp.17433-17440. ⟨10.1039/C9NJ03151K⟩. ⟨hal-02410473⟩