• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.446-451
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• 1999

This study was carried out to investigate some mineralogical characteristics of Artificial Granular Zeolite (AGZ) and effect of AGZ on purification and alleviation of rice seedling damages of mine wastewater containing heavy metals. AGZ had mainly representative Na-P1 peaks and some $C_3S$ peaks of Portland cement in X-ray diffractogram. Differential thermal analysis represented that AGZ had weak endothermic peak around $130^{\circ}C$ and new deep endothermic peak around $750^{\circ}C$ as compared to powdery artificial zeolite. The ranking of heavy metals removals by AGZ, was lead> copper> cadmium> zinc in the synthetic wastewater. Root growth of rice seedling was greatly inhibited in the mine wastewater, and died after all. As AGZ treated into the mine wastewater with the ratio 1 : 50 (W : V) for one day or 1 : 100 for 4 days, the concentrations of heavy metals in the mine wastewater were decreased to below the critical concentration for agricultural use. And rice seedlings were grew with little damages in the purified water by AGZ.

• Membrane Journal
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• v.28 no.6
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• pp.432-443
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• 2018

In this study, propylene/propane separation behavior of Na-type faujasite zeolite membranes is predicted by observing gravimetric adsorptions of propylene and propane on zeolite 13X. The gravimetric adsorptions were measured by using a magnetic suspension balance (MSB) at temperatures of 323, 343, 363 K and a pressure range of 0.02-1 bar. The pressure was increased at 0.1 bar intervals. As adsorption temperature increased, adsorptions of propylene and propane decreased and propylene/propane adsorption selectivity increased. Also, the diffusion coefficients of propylene and propane were increased as the adsorption temperature increased, following the Arrhenius equation. The maximum propylene/propane diffusion selectivity was 0.9753 at 323 K. The perm-selectivity was calculated from the adsorption data of zeolite 13X and compared with the perm-selectivity measured in the single gas permeation experiment for the Na-type faujasite zeolite membrane. The maximum values for the calculated and measured perm-selectivities were observed at a temperature of 323 K. It could be concluded that the prediction of propylene/propane separation of surface diffusion-based membrane by using gravimetric adsorption data is reasonable. Therefore, it is expected that this prediction method can be applied to the screening of adsorption-based microporous membrane for propylene/propane separation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.157-158
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• 2020

The present study examined the effectiveness of textile fabrics coated with nano-pore materials on removing the nitrogen oxide (NO_X) and sulfur oxide (SO_X) in the atmospheric environment. The tested approach is favorable for absorbing NO_X and SO_X, even under the washing condition.

• Journal of radiological science and technology
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• v.29 no.3
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• pp.147-155
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• 2006

The crystal structures of fully dehydrated $K_3Na_8H-A(R_1=0.0478,\;R_2=0.0458\;and\;a=12.257(1){\AA})$ have been studied by single-crystal x-ray diffraction methods in the cubic space group. Pm3m in order to understand the structure of the zeolite as a gas storage medium and the mechanisms based on the encapsulation and decapsulation processes of gas molecules. In the crystal structures of dehydrated $K_3Na_8H-A$, three $K^+$ ions per unit cell are located on the 8-oxygen ring(0.0, 0.4531, 0.4531) and eight $Na^+$ ions per unit cell are located near the centers of 6-oxygen rings. Each $K^+$ ions on the 8-ring is $2.87(2){\AA}$ and $2.79(1){\AA}$ away from two kinds of framework oxygen atoms. These values are more realistic than previously known values in $K_{12}Na-A$. The exact positions of $K^+$ ions are ca. $0.8{\AA}$ away from the centers of the 8-rings which are previously reported as the preferred location of $K^+$ ions. Because the zeolites frameworks are stabilized as the results, more effective controls of gas molecules at encapsulation, decapsulation, and storage are achieved. Additionally, the available storage volumes are also maximized and more volume of gases can be stored in the materials. Therefore, oxygen storage bottles in hospital can be minimized and portable oxygen bottles for patients in emergency can be developed by using the materials.

• Clean Technology
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• v.21 no.3
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• pp.153-163
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• 2015

The effects of H₂O and residue SO₂ in flue gases on the activity of the Fe/zeolite catalysts for low-temperature NH₃-SCR of NO were investigated. And the addition effect of Mn, Zr and Ce to Fe/zeolite for low-temperature NH₃-SCR of NO in the presence of H₂O and SO₂ was investigated. Fe/zeolite catalysts were prepared by liquid ion exchange and promoted Fe/zeolite catatysts were prepared by liquid ion exchange and doping of Mn, Zr and Ce by incipient wetness impregnation. Zeolite NH₄-BEA and NH₄-ZSM-5 were used to adapt the SCR technology for mobile diesel engines. The catalysts were characterized by BET, X-ray diffraction (XRD), SEM/EDS, TEM/EDS. The NO conversion at 200 ℃ over Fe/BEA decreased from 77% to 47% owing to the presence of 5% H₂O and 100 ppm SO₂ in the flue gas. The Mn promoted MnFe/BEA catalyst exhibited NO conversion higher than 53% at 200 ℃ and superior to that of Fe/BEA in the presence of H₂O and SO₂. The addition of Mn increased the Fe dispersion and prevented Fe aggregation. The promoting effect of Mn was higher than Zr and Ce. Fe/BEA catalyst exhibited good activity in comparison with Fe/ZSM-5 catalyst at low temperature below 250 ℃.

• Korean Journal of Crystallography
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• v.1 no.2
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• pp.76-83
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• 1990

The structures of dehydrated fully Ca2+ _exchanged zeolite A (a: 12.2a3(2) A and of its iodine sorption complex (a=12.258(2) A) have been determined by single-crystal X-ray diffraction methods in the cubic space group. Pm3m at 21(1)℃.the structures were refined to final R(weighted) indices of 0.081 with 206 reflections and 0.084 with 173 reflections, respectively for which I>3 w (I). In each structure. six divalent cations are located on three different theefold axes associated with 6-ring oxygens. Dehydrated Ca2+_A sorbs ca. 6.0 diiodine molecules per unit cell at 80℃(vapor pressure of I: is ca. 14.3 Torr). Each iodine molecule makes a close approach. along its ahs to framework oxygen atom with I-I distance of 2.71(2) A, I-O distance of 3.32(3) k. and I-I-0=180℃. The result indicates that diiodine molecule forms charge transfer complex with framework oxygen.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.129.2-129
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• 2003

• Analytical Science and Technology
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• v.16 no.5
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• pp.375-390
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• 2003

A single crystal of fully indium-exchanged zeolite A (In-A) was brought into contact with antimony in a fine Pyrex capillary at $350^{\circ}C$ for 6 days. The reaction was monitored by electron-probe X-ray microanalysis (EPXMA). The crystal structure of antimony-sorbed indium-exchanged zeolite A has been determined by single-crystal X-ray diffraction techniques at $21^{\circ}C$ in the cubic space group Pm ${\bar{3}}m$. The crystal structure of $In_8Si_{12}Al_{12}O_{48}{\cdot}(In)_{1.35}(Sb)_{0.7}$ ($a=12.111(2){{\AA}}$, $R_1=0.071$, and $R_2=0.067$) has 8 indium cations, 1.35 indium atoms, and 0.7 antimony atoms per unit cell. Unit cell 1 ($In_8-A{\cdot}In$, 65% of unit cells) contain the $(In_5)^{8+}$ cluster. In unit cell 2 ($In_8-A{\cdot}(In)_2(Sb)_2$, 35% of unit cells), two $(In_3)^{2+}$ cluster and one $(In_3Sb_2)^{7+}$ cluster are found in the large cavity.

• Journal of the Korean institute of surface engineering
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• v.26 no.6
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• pp.334-340
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• 1993

The physico-chemical properties and characteristics after thermal treatment of natural zeolite from Kampo area were studied. The physico-chemical properties of natural zeolite were studied by investigating chemical composition, x-ray diffraction pattern(XRD), scanning electronic microscope(SEM), infrared spec-tra(IR), thermal analysis(TA), and cation exchange capacity(C.E.C.), and the characteristics of natural zeo-lite after thermal treatment from $400^{\circ}C$ to $900^{\circ}C$ were compared with the natural zeolite. This study showed that clinoptilolite was the predominant costituent in natural zeolite, and the natural zeolite contained a little amount of quartz and feldspar as impurities. Zeolite mineral was seen to develop slowly by the natural alternation of volcanic ash considering the almost amorphous crystal structure. The more temperature of ther-mal treatment increased, the more adsorption capacity decreased, considering the fact that the hydroxy peak diminished on infrared spectra, and that cation exchange capacity also decreased distinctly.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.201-209
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• 2006

Various desorption methods were investigated for an activated carbon and zeolite 13X packed bed after benzene adsorption. Desorption experiments using hot steam, purge gas, and evacuation were performed. As a result, the desorption with hot steam showed the best performance. Hot steam makes the temperature in the adsorption column increase and gives arise to the desorption. Drying process should be accompanied to increase the efficiency because steam vapor prevents the adsorption later. The vacuum desorption showed poor performance and it reveals that temperature swing operation is more effective than pressure swing operation. In the purge gas desorption, good performance was achieved using evacuation.