Synthesis, deposition and characterization of magnesium hydroxide nanostructures on zeolite 4A

Koh, Pei‐Yoong; Yan, Jing; Ward, Jason; Koros, William J.; Teja, Amyn S.; Xu, Bo

doi:10.1016/j.materresbull.2010.12.003

Cited by 11 publications

(10 citation statements)

References 48 publications

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“…The obtained peaks shown in Figure were in accordance with ref. . Figure (a) shows the EDS analysis of zeolite 4A after the conversion reaction.…”

Section: Resultsmentioning

confidence: 99%

“…The following steps were then carried out: (1) 1 g of zeolite 4A was added to the MgCl 2 solution, (2) an NH 4 OH solution was slowly titrated with the mixture during stirring, and (3) the resulting mixture was allowed to sit under ambient conditions for 72 h. After that, the zeolite sample was collected by a Buckner funnel and washed with excess deionized water. The treated zeolites were dried in an oven at 200 °C for 12 h …”

Section: Methodsmentioning

confidence: 99%

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Experimental study of the effect of zeolite 4A treated with magnesium hydroxide on the characteristics and gas‐permeation properties of polysulfone‐based mixed‐matrix membranes

Pakizeh

Hokmabadi

2016

J of Applied Polymer Sci

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Nowadays, new methods for gas-separation processes are being quickly developed. The separation of CH 4 /CO 2 and CH 4 /H 2 is usually the subject of most related research studies, especially in the membrane gas-separation process, because of their important role in industry. In this study, we attempted to improve the separation properties of a polysulfone/zeolite 4A mixed-matrix membrane by modifying the zeolite particle surface. The method included a simple ion-exchange reaction of magnesium chloride with ammonium hydroxide that yielded the formation and precipitation of magnesium hydroxide whiskers on the surface of the zeolites. The whiskers could omit most of the nonselective voids by interlocking the polymer chains through them and, consequently, improve the permeability, selectivity, and elastic modulus of the membranes. X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and dynamic mechanical analysis proved all the changes recorded after the particle and membrane treatments. SEM images showed the petal-like morphology of the whiskers that formed on the surface of the particles after the reaction against the smooth surface of the untreated zeolite. At a 30 wt % loading of particles in the polymeric matrix, the selectivities for H 2 /CH 4 and CO 2 /CH 4 increased by 69 and 56%, respectively; in contrast, the H 2 and CO 2 permeabilities decreased by 2.5 and 10%, respectively. The modulus of elasticity for the treated membrane also increased by 14 and 30% compared to those of the pure and untreated membranes, respectively.

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“…The obtained peaks shown in Figure were in accordance with ref. . Figure (a) shows the EDS analysis of zeolite 4A after the conversion reaction.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Experimental study of the effect of zeolite 4A treated with magnesium hydroxide on the characteristics and gas‐permeation properties of polysulfone‐based mixed‐matrix membranes

Pakizeh

Hokmabadi

2016

J of Applied Polymer Sci

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“…Therefore, the basic Mg(OH) 2 interacts with the bridging hydroxyl protons via an acid-base reaction. The acidic bridging hydroxyl group donates a proton to Mg(OH) 2 forming MgOH þ and water molecules [22]. The resulting MgOH þ will then accept a lone pair of electrons from the deprotonated bridging hydroxyl, which now acts as a Lewis base.…”

Section: Discussionmentioning

confidence: 99%

“…The resulting MgOH þ will then accept a lone pair of electrons from the deprotonated bridging hydroxyl, which now acts as a Lewis base. The precipitated MgOH groups then undergo condensation with each other via oxolation [22], leading to the formation of a hydroxide network. In the oxolation reaction, a nucleophilic substitution takes place with Mg-OH as the nucleophile and OH À or H 2 O as the leaving group.…”

Section: Discussionmentioning

confidence: 99%

“…The TGA curve of virgin zeolite 4A shows weight loss intervals at 443 and 683 K, corresponding to the exclusion of adsorbed water and occluded water molecules [22]. In treated zeolite 4A, the first weight loss stage at 443 K corresponds to the desorption of physisorbed water from the surface of zeolite and Mg(OH) 2 nanopetals [22]. All of the treated zeolite 4A obtained from experiments A2, A6, A9, A10, A11, and A12 experienced similar weight loss at this stage.…”

Section: Thermogravimetric Analysis (Tga)mentioning

confidence: 99%

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Precipitation and growth of magnesium hydroxide nanopetals on zeolite 4A surfaces

Koh¹,

Yan²,

Teja³

2011

Journal of Crystal Growth

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Synthesis and characterization of NaA zeolite powder/film deposited on alumina beads by dip-coating method

Keerthana¹,

Agilan²,

Muthukumarasamy³

et al. 2014

J Sol-Gel Sci Technol

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Linde Type A (LTA) zeolites have been synthesized in the current study by simple sol-gel technique. The crystal growth has been controlled by varying the hydrogel synthesis time and annealing temperature. The resulting products obtained at various crystallization times and temperatures have been studied using X-ray powder diffraction (XRD) method, High resolution transmission electron microscopy images, scanning electron microscopy (SEM) micrographs, energy dispersive study and Brunauer-Emmett-Teller (BET) analysis. The TEM images of the final LTA zeolite annealed at 500°C revealed the formation of cubic structure. XRD analysis revealed that the crystallinity improved with annealing. BET analysis revealed that the synthesized LTA is a well crystallized 4A zeolite. LTA zeolites were dispersed in poly ethylene glycol in the ratio 3:100 and 5:100 and coated on porous alumina beads for the formation of membrane. The SEM images revealed excellent formation of fine structure LTA zeolite membrane with uniform coating. The membrane consisted of a top layer with thickness of 1.14-2.0 lm. Crystals in the top layer showed cubic morphology and amorphous phase was observed at the grain boundaries present between LTA zeolite and alumina substrate.

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Synthesis, deposition and characterization of magnesium hydroxide nanostructures on zeolite 4A

Cited by 11 publications

References 48 publications

Experimental study of the effect of zeolite 4A treated with magnesium hydroxide on the characteristics and gas‐permeation properties of polysulfone‐based mixed‐matrix membranes

Experimental study of the effect of zeolite 4A treated with magnesium hydroxide on the characteristics and gas‐permeation properties of polysulfone‐based mixed‐matrix membranes

Precipitation and growth of magnesium hydroxide nanopetals on zeolite 4A surfaces

Synthesis and characterization of NaA zeolite powder/film deposited on alumina beads by dip-coating method

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