Synthesis and characterization of zeolites from sodium aluminosilicate solution
Loading...
Date
2007
Authors
Siti Aida, Ibrahim
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A series of synthetic zeolites were successfully synthesized from sodium
aluminosilicate solutions with varying Si concentration from 1 to 8 molar using fumed
silica and sodium aluminate. The order of mixing and the effect of varying amount of Si
in the sodium aluminosilicate solution towards gelation, crystallization, phases,
physico-chemical characteristics and surface morphology were studied. Data concerning the in-situ monitoring of sodium aluminosilicate gelation behavior and the
crystallization time at room temperature are reported. XRD results showed that the
phases of zeolites synthesized are similar to FAU, LTA, SOD and GIS framework. The
crystallite size was found to vary from 3 to nearly 20 nm. The physico-chemical
characteristics of the product were obtained from Malvern particle size analyzer, BET
and FTIR. From Malvern analysis, it was found that the average particle sizes (d50) of
synthetic zeolites were varied from 12 micron to 95 micron while the highest surface
area values obtained from BET was about 9.84 m2/g. Meanwhile, FTIR spectra
exhibited the presence of internal Si-O-(Si) and Si-O-(Al) vibrations in the tetrahedra or
alumino- and silico-oxygen bridge in the range of 1200 – 400 cm-1, while the presence
of zeolite water in the range of 1600- 3700 cm-1 and the pseudo-lattice vibrations of
structural unit in the range of 500-700 cm-1. Surface morphological studies obtained
from SEM photomicrographs showed the powdered synthetic zeolite have a lamellar
structure with cubical edge and the crystal size was estimated to be 1 to 1.2 micron.
TEM photomicrographs showed the presence of pores with the pore sizes estimation at
13-23 nm (width) and 18-43 nm (length). Finally, the highest CEC value of the
synthesized zeolites against ammonium was obtained at 66.3 meq/100g meanwhile the
lowest was at 7.65 meq/100g at optimum contact of 12 hours.
Description
Master
Keywords
Materials and Mineral Resources Engineering , Zeolites , Sodium Aluminosilicate Solution