H Maghsoodloorad | Iran University of Science and Technology (IUST) (original) (raw)

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Papers by H Maghsoodloorad

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and numb... more In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W-type zeolite membranes synthesized over flat SUS supports for O 2 /SF 6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O 2 /SF 6 , however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O 2 /SF 6 , and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W-type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.

International Journal of Applied Ceramic Technology, 2012

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and numb... more In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W-type zeolite membranes synthesized over flat SUS supports for O 2 /SF 6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O 2 /SF 6 , however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O 2 /SF 6 , and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W-type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.

Clays and Clay Minerals, 2011

ABSTRACT The objectives of this study were to investigate the effects of chemical parameters on t... more ABSTRACT The objectives of this study were to investigate the effects of chemical parameters on the characterization of W-type zeolite crystals and their intergrowths with other types of zeolites. The crystal size and purity of W-type zeolites are affected significantly by the gel composition with respect to the molar ratios of SiO2 /Al2O3 (aluminosilicate module, a), H2O/K2O (alkainity, b), and water content (H2O/SiO2 ,g). The effects of these gel parameters on the synthesis and characterization of W-type zeolite were investigated. Crystalline W-type zeolite of high purity was synthesized using a gel with a molar ratio of Al2O3 :6.4SiO2:5.6K2O:164.6H2O at T = 165ºC for a period of 72 h. The effect of excess K2O/SiO2 ratio in a mono-cation (K)-SiO2 -Al2O3 gel-composition system on the nanoparticle size and purity of the product was also investigated. Experiments were carried out using the following levels of alkalinity: 21.4, 29.4, and 51.9; aluminosilicate module: 5.0, 6.4, and 10.0; water content: 16.5, 25.7, and 32.9; and excess K2O/SiO 2 ratio : from 0.65 to 3.33. The results showed that by increasing the aluminosilicate module at high K2O/SiO2 ratio, the crystallinity and crystal size of the zeolite synthesized increased, while at low alkalinity, the crystallinity and crystal size decreased. Decreasing alkalinity at low aluminosilicate module increased the crystallinity and decreased the crystal size, while at high aluminosilicate module, both decreased. Finally, by increasing the water content at all aluminosilicate module and alkalinity values, the crystallinity and crystal size of the W-type zeolite increased. Excess K2O/SiO2 ratio was the key factor that should be adjusted in the range 0.7À1.0 for synthesis of pure crystals of W-type zeolite.

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and numb... more In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W-type zeolite membranes synthesized over flat SUS supports for O 2 /SF 6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O 2 /SF 6 , however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O 2 /SF 6 , and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W-type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.

International Journal of Applied Ceramic Technology, 2012

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and numb... more In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W-type zeolite membranes synthesized over flat SUS supports for O 2 /SF 6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O 2 /SF 6 , however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O 2 /SF 6 , and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W-type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.

Clays and Clay Minerals, 2011

ABSTRACT The objectives of this study were to investigate the effects of chemical parameters on t... more ABSTRACT The objectives of this study were to investigate the effects of chemical parameters on the characterization of W-type zeolite crystals and their intergrowths with other types of zeolites. The crystal size and purity of W-type zeolites are affected significantly by the gel composition with respect to the molar ratios of SiO2 /Al2O3 (aluminosilicate module, a), H2O/K2O (alkainity, b), and water content (H2O/SiO2 ,g). The effects of these gel parameters on the synthesis and characterization of W-type zeolite were investigated. Crystalline W-type zeolite of high purity was synthesized using a gel with a molar ratio of Al2O3 :6.4SiO2:5.6K2O:164.6H2O at T = 165ºC for a period of 72 h. The effect of excess K2O/SiO2 ratio in a mono-cation (K)-SiO2 -Al2O3 gel-composition system on the nanoparticle size and purity of the product was also investigated. Experiments were carried out using the following levels of alkalinity: 21.4, 29.4, and 51.9; aluminosilicate module: 5.0, 6.4, and 10.0; water content: 16.5, 25.7, and 32.9; and excess K2O/SiO 2 ratio : from 0.65 to 3.33. The results showed that by increasing the aluminosilicate module at high K2O/SiO2 ratio, the crystallinity and crystal size of the zeolite synthesized increased, while at low alkalinity, the crystallinity and crystal size decreased. Decreasing alkalinity at low aluminosilicate module increased the crystallinity and decreased the crystal size, while at high aluminosilicate module, both decreased. Finally, by increasing the water content at all aluminosilicate module and alkalinity values, the crystallinity and crystal size of the W-type zeolite increased. Excess K2O/SiO2 ratio was the key factor that should be adjusted in the range 0.7À1.0 for synthesis of pure crystals of W-type zeolite.