PHASE TRANSFORMATIONS OF NATURAL ZEOLITES under ACID AND ALKALI TREATMENTS
Abstract
The change of zeolite properties of the ‘Noyemberyanskoe’ deposit (Armenia) after their processing with alkaline and acidic solutions (16 mol/dm3 ) has been studied by Xray diffraction and dip pycnometry. It has been established that chemical composition and specific total pore volume of clinoptilolite were changed, and also new phases, such as sodalite, gismondine and fillipsite, were formed at sodium hydroxide concentration of ≥ 2 mol/dm3 . It has been found that increasing the hydrochloric acid concentration up to ≈ 6 mol/dm3 leads to size and form change of clinoptilolite sorption channels, and further increase causes its destruction. The method of lowtemperature nitrogen adsorptiondesorption proved the presence of mesoporous constituent in a clinoptilolite rock.
Keywords
About the Authors
A. O. Sargsyan
Yerevan State University
Armenia
Armenia
O. A. Sargsyan
Yerevan State University
Armenia
Armenia
L. R. Harutyunyan
Yerevan State University
Armenia
Armenia
G. G. Badalyan
Yerevan State University
Armenia
Armenia
I. A. Petrosyan
Yerevan State University
Armenia
Armenia
R. S. Harutyunyan
Yerevan State University
Armenia
Armenia
T. F. Kouznetsova
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus
Belarus
Belarus
A. I. Ivanets
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus
Belarus
Belarus
References
1. Armbruster, T. Dehydration Mechanism of Clinoptilolite and Heulandite: Single-Crystal X-Ray Study of Na-Poor, Ca-, K-, Mg-Rich Clinoptilolite at 100 K // Amer. Mineralog. – 1993. – Vol. 78. – P. 260–265.
2. Баррер, Р. Гидротермальная химия цеолитов / Р. Баррер. – М.: Мир, 1985. – 420 с.
3. Химия цеолитов и катализ на цеолитах: под ред Дж. Рабо. В 2-х т. М.: Мир, 1980.
4. Lin, H. Physicochemical Properties and Mechanism Study of Clinoptilolite Modified by NaOH / H. Lin, Q. Liu, Y. Dong, He Yin-hai [et al.] // Microp. Mesopor. Mater. – 2015. – Vol. 218. – P. 174–179.
5. Брек, Д. Цеолитовые молекулярные сита / Д. Брек. – М.: Мир, 1976. – 781 с.
6. Ivanova, E. Ethanol Vapours Adsorption by Natural Clynoptilolite / E. Ivanova, M. Karsheva // J. Univer. Chem. Technol. and Metallurgy. – 2007. – Vol. 42, N 4. – P. 391–398.
7. Onal, M. Preparation and Characterization of Acid-activated Bentonite Powders / M. Onal, Y. Sarıkaya // Powder Technology. – 2007. – Vol. 172, N 1. – P. 14–18.
8. Epelde, E. Controlling Coke Deactivation and Cracking Selectivity of MFI Zeolite by H3PO4 or KOH Modification / E. Epelde, J. I. Santos, P. Florian [et al.] // Appl. Cat. A: General. – 2015. – Vol. 505. – P. 105–115.
9. Jin, Y. Ch. Mesopore Modification of Beta Zeolites by Sequential Alkali and Acid Treatments: Narrowing Mesopore Size Distribution Featuring Unimodality and Mesoporous Texture Properties Estimated Upon a Mesoporous Volumetric Model / Y. Ch. Jin, J. Liu [et al.] // Micropor. and Mesopor. Mater. – 2015. – Vol. 218. – P. 180–191.
Review
Views: 602
Email this article 