Synthesis of zeolite NaA nano-crystalls; effect of synthesis parameters on crystallinity and crystal size

Document Type: Full article

Author

Mechanical and Energy Department, Shahid Beheshti University A.C., Tehran, Iran

Abstract

Abstract
In this work hydrothermal synthesis of zeolite NaA crystals with a composition of Al2O3:aSiO2:bNa2O:cH2O was investigated. Effects of SiO2/Al2O3, Na2O/Al2O3 and H2O/Al2O3 ratios and crystallization temperature and time were studied on crystallinity and crystal size of zeolite NaA crystals. It was tried to understand the interactions between these parameters. The crystal species of zeolite NaA were characterized by XRD and SEM.
Considering the interactions between these parameters showed that effects of increasing SiO2/Al2O3 and Na2O/Al2O3 ratios simultaneously neutralize each other so that their overall effect is not significant. On the other hand, the effects of increasing SiO2/Al2O3 and H2O/Al2O3 ratios reinforce each other and significantly affect crystallinity and crystal size. Increasing alkalinity increases crystallization rate and reduces synthesis time. Also, effects of increasing crystallization temperature and time simultaneously reinforce the effects of each other.
The effect of decreasing alkalinity is moderated with that of increasing Na+ content in the synthesis gel.

Keywords

Main Subjects


[1]      Cejka, J., Van Bekkum, H., Corma, A. and Schüth, F., Introduction to zeolite science and practice, 3rd ed., Elsevier Science, Hungary, (2007).

[2]      Yin, C., Wen, G., Tian, D., Bao, X. and Chen, Y., “One-pot synthesis of hierarchically nanoporous zeolite beta via resin template”, Synth. React. Inorg. M., 44 (3), 413 (2014).

[3]      Shah, D., Kissick, K., Ghorpade, A., Hannah, R. and Bhattacharyya, D., “Pervaporation of alcohol-water and dimethylformamide-water mixtures using hydrophilic zeolite NaA membranes: Mechanisms and experimental results”, J. Membr. Sci.,179, 185 (2000).

[4]      Nunes, S. P. and Peinemann, K. V., Membrane technology in the chemical industry, John Wiley and Sons, New York, (2001).

[5]      Chapman, P. D., Oliveira, T., Livingston, A. G. and Lia, K., “Review: Membranes for the dehydration of solvents by pervaporation”, J. Membr. Sci.,318, 5 (2008).

[6]      Sato, K., Aoki, K., Sugimoto, K., Izumi, K., Inoue, S., Saito, J., Ikeda, Sh. and Nakane, T., “Dehydrating performance of commercial LTA zeolite membranes and application to fuel grade bio-ethanol production by hybrid distillation/vapor permeation process, Micropor. Mesopor. Mat.,115, 184 (2008).

[7]      Kyotani, T., Mizuno, T., Katakura, Y., Kakui, S., Shimotsuma, N., Saito, J. and Nakane, T., “Characterization of tubular zeolite NaA membranes prepared from clear solutions by FTIR-ATR, GIXRD and FIB-TEM-SEM”, J. Membr. Sci.,296, 162 (2007).

[8]      Li, Y., Zhoua, H., Zhua, G., Liu, J. and Yang, W., “Hydrothermal stability of LTA zeolite membranes in pervaporation”, J. Membr. Sci.,297, 10 (2007).

[9]      Goryainov, S. V., Secco, R. A., Huang, Y. and Liu, H., “Amorphization and post-amorphous phases of NaA Zeolite at high P–T conditions”, High Pressure Res.,26, 395 (2006).

[10]  Treacy, M. M. J. and Higgins, J. B., Collection of simulated XRD powder patterns for zeolites, 4th ed., Elsevier Science, (2001).

[11]  Corma, A., Rey, F., Rius, J., Sabater, M. J. and Valencia, S., “Supramolecular self-assembled molecules as structure directing agents for the synthesis of zeolites”, Nature, 431, 287 (2004).

[12]  Xiao-Yong, Q., Qian, W., Hui-Jun, X., Jian-Chun, Z. and Qing-Yang, D., “Effect of the aging temperature on the synthesis of small crystal LTA zeolites”, Mater. Res. Innov.,20, 161 (2015).

[13]  Cundy, C. S., Lowe, B. M. and Sinclair, D. M. J., “Crystallization of zeolitic molecular sieves: Direct measurements of the growth behavior of single crystals as a function of synthesis conditions”, Chem. Faraday Discuss, 95, 235 (1993).

[14]  Vasanth, D., Pugazhenthi, G. and Uppaluri, R., “Preparation, characterization, and performance evaluation of LTA zeolite-ceramic composite membrane by separation of BSA from aqueous solution”, Sep. Sci. Technol.,52, 767 (2016).

[15]  Camblor, M. A., Villaescusa, L. A. and Diaz-Cabanas, M. J., “Synthesis of all silica and high silica molecular sieves on fluoride media”, Top. Catal., 9, 59 (1999).

[16]  Mirfendereski, S. M., Daneshpour, R. and Mohammadi, T., “Synthesis and characterization of T-type zeolite membrane on a porous mullite tube”, Desalination, 200, 77 (2006).

[17]  Maghsoodloorad, H., Mirfendereski, S. M., Mohammadi, T., Pak, A., “Effects of gel parameters on the synthesis and characteristics of W-type zeolite nanoparticles”, Clay Clay Miner., 59 (3), 328 (2011).

[18]  Cichocki, A. and Kos´cielniak, P., “Experimental designs applied to hydrothermal synthesis of zeolite ERI+OFF(T) in the Na2O–K2O–Al2O3–SiO2–H2O system Part 2. Regular study”, Micropor. Mesopor. Mat., 29, 369 (1999).