• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1570-1576
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• 1994

Effect of Na2O/SiO2 molar ratio, calcining temperature and addition of NaCl were investigated on the hydrothermal formation of X-type zeolite from the natural mordenite, which is a kind of rock deposited abundantly in kuryong po. Pulverized mordenite was first mixed with NaOH or NaOH-NaCl solution, and crystallized under hydrothermal condition at 90~10$0^{\circ}C$ for 10 hrs. Optimum condition for synthesis of the X-type zeolite were \circled1 the ratio Na2O/SiO2, NaCl/Al2O3 and H2O/Na2O:0.68, 11.4 and 40, respectively, \circled2 calcining temperature of starting materials: 90$0^{\circ}C$, \circled3 aging time: 48 hrs. and \circled4 crystallization temperature: 10$0^{\circ}C$. The yield of X-type zeolite under the optimum condition was about 55~60%, and the major crystallized X-type zeolite was faujasite phase. Zeolite of then type X was crystallized when NaCl was added to treating solution with in the limit 14.25 of NaCl/Al2O3 molar ratio. As the calcination temperature (from 50$0^{\circ}C$ to 95$0^{\circ}C$) of starting materials increases, yield of zeolite x increase.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.361-372
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• 1994

Vanadium containing MFI type zeolites have been prepared hydrothermally or by the impregnation method with $NH_4VO_3$ solution after dealumination of HZSM-5. Incorporation of vanadium into the framework of zeolite has been demonstrated by XRD, DTA, FT-IR and ESR analyses. Upon $NH_4VO_3$ impregnation and calcination of dealuminated zeolite, vanadium substitution into the framework could be performed like a hydrothermally synthesized zeolite. Vanadium in zeolite is able to pass redox cycles at high temperatures, and it is shown that vanadium is probably fixed and atomically dispersed in the structure of zeolite. The catalytic benzene hydroxylation, hexanes and alcohols oxidation were used for evaluating the properties of vanadium incorporated MFI zeolite.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.243-248
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• 2005

Membrane pervaporation processes could have advantages over distillation for separation of water/organics mixtures: a low energy demand and the ability to separate azeotropic mixtures or isomers. Zeolite membranes might show better thermal, mechanical and chemical stabilities than polymer membranes. Water could be effectively separated from water/organic mixtures using the NaA zeolite membrane because of its high hydrophilicity. In this study, water was separated by pervaporation using the NaA zeolite membrane from water/ethanol mixtures. As a mole fraction of ethanol increased, the total permeation flux and the water flux decreased while the separation factor increased, reached a maximum point, and decreased. As an experimental temperature increased, the total permeation flux increased while the separation factor increased at the lower mole fraction of ethanol than 0.8 and it decreased at the higher mole fraction of ethanol than 0.8. The total permeation flux and the separation factor could be maintained constant during the long term experiment longer than 160 hours. It was found that the NaA zeolite membrane synthesized in our study showed better performance on water/ethanol separation than that of a distillation process or PVA polymeric pervaporation membranes.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.214-218
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• 2011

Zeolite A was synthesized from coal fly ash by the microwave heating as well as the conventional heating method. The effects of reaction time, the amount of sodium aluminate, and the reaction temperature on the crystallization of zeolite A were investigated. The optimum crystallization time was about 3 to 6 h in the temperature range of $80{\sim}100^{\circ}C$. The amount of sodium aluminate was found to be optimum when the molar ratio $SiO_2/Al_2O_3$ of starting solution was in the range of 0.44 to 1.05 at above $90^{\circ}C$, However, The more amount of sodium aluminate was required to get zeolite A at $80^{\circ}C$. Although the rate of crystallization was slightly faster in the microwave heating than that in the conventional heating, the reaction time need to obtain fully crystallized zeolite A was similar in both methods. Therefore, the influence of the microwave heating was not so large compared with the conventional heating in the synthesis of zeolite A from coal fly ash.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.624-630
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• 1997

Zeolite A helps an increase of detergency performance according to showing the ion exchange effect for polyvalant ions and it's detergency performance could be calculated quantitatively by using the disperse stabilization theory because it is water-insoluble material and is as colloid particles in aqueous solution. In this study, zeta potential of carbon black, cellulose, and Zeolite A were measured in each inorganic salt solutions and applied to the theory of Heterocoagulation in order to evaluate the detergency performance of Zeolite A about the particulate soil at the view point of interaction potential energy. Zeolite A was shown help an increase of detergency performance according to the increasing of the steric repulsion between Zeolite A and cellulose in $Na2CO_3$ solution and the decrease of re-deposition of carbon black on the fabric by rapid coagulation with carbon black in $Na_2SO_4$ solution.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.687-694
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• 2012

Zeolite 4A was synthesized by fusion method from coal fly ash discharged at the thermal power plants. The synthesized zeolite(FAZ) was characterized through particle size analyzer, XRD, XRF and SEM. $N_2$ adsorption-desorption measurement was used to examine surface and pore structures. The adsorption experiments were carried out under dynamic conditions of trace $SO_2$ in $N_2$ to investigate $SO_2$ adsorption capacity of FAZ. The experiments were conducted to characterize the breakthrough characteristics of $SO_2$ in a fixed bed under different operating conditions including temperature(50-$125^{\circ}C$), concentration of $SO_2$(3000-10000 ppm) and FAZ with 4 kinds of commercial zeolite. The adsorption capacity of FAZ was 53.84 $mgSO_2/g$ adsorbent, larger than that of the same type commercial zeolite(WK4A).

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.65-75
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• 2013

In this study, the engineering characteristics of volcanic ash-cement soil mixtures and zeolite-cement soil mixtures are investigated by using unconfined compression test, freezing-thawing test, SEM and XRD analysis. The samples were mixed with volcanic ash from Mt. Baekdusan or porous zeolite, and cement as the ratios of 3.5:1, 4.0:1, 4.5:1, 5.0:1 with and without metakaolin. It is confirmed that compressive strength degraded with increasing of the amount of volcanic ash or zeolite, and increased with addition of metakaolin as a binder. Moreover, test results suggested that the mixtures provided sufficient freezing-thawing resistance. In addition, ettringite as a product of cement hydration was detected by SEM and XRD, and that possibly contributes to the strength of the mixtures.

• Korean Chemical Engineering Research
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• v.44 no.3
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• pp.243-247
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• 2006

MFI zeolite membranes were prepared on anodic alumina (Anodisc) as support. First, silicalite-1(${\approx}1.2{\mu}m$) seed crystals were attached to the surface of the support via chemical bonding, and the a- and b-axis oriented zeolite membranes could be synthesized on the support coated with the monolayer of the seed crystals by secondary growth hydrothermal synthesis. The zeolite membranes prepared were characterized using scanning electron microscope and analyzed by X-ray diffraction.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.505-510
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• 2005

The objective of this study was to remove non-biodegradable matters and ammonia ion in livestock wastewater using Fenton oxidation and Zeolite adsorption process. After coagulation process as 1st treatment, non-biodegradable matters remained after 1st treatment were removed by using OH radical produced in Fenton oxidation process. Zeolite as cation adsoption process was used to remove ammonia ion in 2nd treatment water. As a result of treatment using these processes, NBDCOD removal efficiency was over 90% and ammonia ion was almost removed. Most aromatics or polynuclear aromatics like benzene, phenol and scatol in livestock wastewater wasn't detected after Fenton oxidation process.

• Journal of the Korean institute of surface engineering
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• v.25 no.3
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• pp.144-149
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• 1992

The adsorption and molecular sieve characteristics of water, methanol, ethanol, butanol and benzene on acid-alkali treated natural zeolite from Kampo area were investigated by the Diamond·Kinter method, and it was compared with synthetic zeolite A. Adsorption amount of water increased with the treatment of acid rather than the treatment of alkali. Similar tendency was observedd in adsorption of alcohols such as methanol, ethanol and butanol, but the amount of adsorption decreased. From the views of the molecular size, adsorption amount of benzene decreased because of surface activity according to the cations species rather than chemical treatment. And it was almost same value that the amount of adsorption was compared acid treated natural zeolite with synthetic zeolite A.