• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.6-13
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• 1999

NaX zeolite crystal were grown from seed elements of synthetic NaX(2~3$\mu\textrm{m}$) Powder in a mother liquor having an approximate reactant composition ${4.12{Na}_{2}O{\cdot}{Al}_{2}{O}_{3}{\cdot}3.5{SiO}_{2}{\cdot}593{H}_{2}O$.The result was that crystallization time of NaX zeolite was reduced with adding seed materials to the initial mixture and crystal size was reduced . but with increasing crystallization time, NaX zeolite. In this study, We investigated detailed factors which NaX crystal has been determined by a combination of SEM, XRD, FT-IR, and BET.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.13-21
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• 2023

X-ray powder diffraction study was conducted on the bulk modulus and phase transition behavior of synthetic zeolite X under high temperature and high pressure. Water and HCO₃^- solution were used as a PTM. Sample was heated and pressurized up to 250 ℃ and 5.18 GPa. The change of unit cell volume and phase transition were observed by X-ray diffraction. The lattice constants and unit cell volume of zeolite X, gmelinite, natrolite, and smectite were calculated using the GSAS2 program to which Le Bail's whole powder pattern decomposition (WPPD) method was applied. The bulk modulus of each zeolite X and smectite were calculated using the EosFit program to which the Birch-Murnaghan equation was applied. The bulk modulus of zeolite X is 89(3) GPa in water run, and zeolite X is 92(3) GPa in HCO₃^- solution run. In both run, pressure induced hydration (PIH) occurred due to the inflow of PTM into the zeolite X framework at initial pressure. Zeolite X transited to gmelinite, natrolite, and smectite in water run. Zeolite X, however, transited to smectite in HCO₃^- solution run. Interzeolite transformation occurred in water run, and did not occur in HCO₃^- solution run, which is assumed that conflict between the environment to form zeolite and the pH of the HCO₃^- solution.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.594-603
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• 2018

The effects of operating conditions such as benzene concentration, nitrogen flow rate, steam flow rate, and bed temperature on TSA process were experimentally investigated as a potential VOC removal technology using two kinds of beds packed with activated carbon and zeolite 13X. The TSA cycle studied was composed of the adsorption step, steam desorption step, and drying and cooling step. At 2% benzene concentration, the total adsorption amounts of zeolite 13X and activated carbon were 4.44 g and 3.65 g, respectively. Since the zeolite 13X has a larger packing density than that of the activated carbon, the larger benzene amount could be adsorbed in a single cycle. Increasing the water vapor flow rate to 75 g/hr at 2% benzene concentration reduced the desorption time from 1 hr to a maximum of 33 min. If the desorption time is shortened, the drying and cooling step period can be relatively increased. Accordingly, the steam removal and bed cooling could be sufficiently performed. The desorption amounts increased with the increase of the bed temperature. However, the energy consumption increased while the desorption amount was almost constant above $150^{\circ}C$. In the continuous cycle process, when the amount of remained benzene at the completion of the regeneration step increased, it might cause a decrease in the working capacity of the adsorbent. The continuous cycle process experiment for zeolite 13X showed that the amount of remained benzene at the end of regeneration step maintained a constant value after the fourth cycle.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.358-367
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• 2019

Adsorption equilibrium and intraparticle diffusion characteristics of benzene, toluene, and xylene vapors on activated carbon and zeolite 13X were investigated. Static adsorption experiments were carried out under the pressure range of 0.01~0.07 bar while changing the adsorption temperature to 293.15 K, 303.15 K, and 313.15 K, respectively. Adsorption equilibrium was analyzed by Langmuir, Freundlich and Toth models. The adsorption energy was 5.26~31.0 kJ/mol representing physical adsorption characteristics. The maximum adsorption capacity on activated carbon was the largest for benzene, and the smallest for xylene. Toluene was in between. In the case of zeolite 13X, the maximum adsorption capacity was the largest for xylene, and the smallest for benzene as opposed to activated carbon. The effective diffusion coefficients of gas adsorbate were measured to be about $10^{-5}{\sim}10^{-4}cm^2/s$, and increased with temperature. As the pressure increased, the effective diffusion coefficients were decreased. The dependence of effective diffusion coefficients on temperature and pressure was greater in zeolite 13X particles than in activated carbon. Therefore, it is necessary to express the diffusion coefficients as a function of pressure in order to predict the precise dynamic behavior of the adsorption process using zeolite 13X where the pressure fluctuation occurs abruptly.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.838-846
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• 2016

Most of combustion processess used in industries require recovering or removing flue gas components. Recently a new MBA (moving bed adsorption) process for recovering $CO_2$ using zeolite 13X was developed. In this study, adsorption experiments for carbon dioxide, nitrogen, sulfur dioxide, and water vapor on zeolite 13X were carried out. Adsorption equilibrium and adsorption rate into solid particle were investigated. Langmuir, Toth, and Freundlich isotherm parameters were calculated from the experiment data at various temperatures. Experimental results were consistent with the theoretically predicted values. Also $CO_2$ adsorption amount was measured under the conditions with impurities such as $SO_2$ and $H_2O$. Binary adsorption data were well fitted to the extended Langmuir isotherm using parameters obtained from pure component experiment. However, $H_2O$ impurity less than, roughly, ${\sim}10^{-5}H_2O\;mol/g$ zeolite 13X enhanced slightly $CO_2$ adsorption. Spherical particle diffusion model well described experimentally measured adsorption rate. Diffusion coefficients and activation energies of $CO_2$, $SO_2$, $N_2$, $H_2O$ were obtained. Diffusion coefficients of $CO_2$ and $SO_2$ decreased with small amount of preadsorbed impurity. Parameter values from this study will be helpful to design of real commercial adsorption process.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.131-138
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• 2005

Freundlich isotherms and Toth isotherms were obtained for benzene adsorption on activated carbon and zeolite 13X in static experiments. Breakthrough curves of benzene were measured in adsorption bed packed with the same adsorbents. Relation between breakthrough times and partial pressure of benzene was analyzed and the Freundlich isotherm parameters were determined. Adsorption amount of benzene predicted by the analysis of breakthrough experimental results was relatively consistent with that predicted by the static experimental results. Dynamic experiments for activated carbon bed, where more symmetric breakthrough curves were obtained, produced smaller errors with zeolite bed.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.307-312
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• 2008

Rietveld analysis using synchrotron X-ray powder diffraction data collected at 15 K reveals that CFC-13 ($CF_{3}Cl;$ chlorotrifluoromethane) sorbed on Na,K-LSX binds through fluorine to sodium ions around the single 6-ring aperture in the supcrgage.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.123-130
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• 2005

Zeolite X adsorbents with large surface area were prepared for using oxygen PSA adsorbent. Selective adsorption performance of nitrogen on the synthesized zeolite X adsorbent was improved by the cation exchange of adsorbent. The zeolite X which had over $650m^2/g$ surface area was synthesized at the conditions of $SiO_2\;:\;Na_2O\;:\;H_2O\;:\;Al_2O_3$ = 2.5 : 3.5 : 150 : 1 mole ratio, $98^{\circ}C$ temperature and 18 h synthesized time in 50 L reactor. The metal ions Li, Ag, Ca, Br, Sr, etc. were investigated for ion exchange with zeolite X. Ag ion was showed the highest ion exchange rate among these metal ions and all metal ions were exchanged with Na ion at equivalent rate. Compared with the NaX adsorbent, the ion exchanged zeolite X adsorbent remarkably improved its adsorption performance of nitrogen at the conditions of $10{\sim}40^{\circ}C$ temperature and 0~9 atm pressure. At an equilibrium pressure under 0.5 atm, adsorption performance of nitrogen on the ion exchanged zeolite adsorbent increased in the order of Ag > Li > Ca > Sr> Ba > K, whereas at an equilibrium pressure over 1 atm showed in the order of Li > Ag > Ca > Sr > Ba > K. Nitrogen/oxygen separation factor of Li ion exchanged zeolite X adsorbent was 13.023 at the partial pressure of nitrogen/oxygen gas mixture similar to air and $20^{\circ}C$ adsorption temperature.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.172.1-172.1
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• 2011

본 연구에서는 매립지에서 발생하는 주요한 가스인 $CO_2$(47~55%)와 $CH_4$(47~55%)가스를 분리하기 위하여 여러 $CO_2$ capture 방법 중 Zeolite를 사용한 흡착법을 이용하였다. 국내에서 시판되고 있는 powder형 Zeolite 13X에 Inorganic binder와 organic binder를 최적의 비율로 혼합한 후 증류수를 이용하여 Pellet type 흡착제를 제조하였다. 또한 최종적으로 $CO_2$의 흡착능을 높이기 위하여 양이온(1M의 KCl, NaCl, $CaCl_2$, $LiCl_2$)으로 이온교환을 하였다. 매립지 모사가스($CO_2$:40%, $CH_4$:60%)를 이용하여 실시간 분석기(Delta1600S)를 이용 두 가스의 분리와 $CO_2$ 흡착성능(mg-CO2/g-흡착제)을 확인하였다. 개발된 흡착제(AjouEpl 13X)는 ICP, XRD, XRF, BET 분석으로 제올라이트의 구조와 성분을 분석하였다.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.949-956
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• 1994

The objective of this study is to experimentally investigate the ion exchange characteristics of five types of Zeolite(Zeolite-A, 13X, Y, Mordenite, Chabazite) for effective removal of Cs, Sr and Co ions in water solution at low concentration(0.01 N and 0.005 N). Total ion exchange capacity and equilibrium isotherm are measured, and free-energy change(${\Delta}G^0$) and enthalpy change(${\Delta}H^0$) in ion exchange reaction are calculated from experimental results. In addition the ion exchange equilibrium in the three-component system for three types of zeolite showing better efficiency is measured and plotted in triangle coordinates. It is shown from experimental results that the magnitude of free-energy change increases with the increasing ion selectivity, and the difference of free energy change between ions correlates closely with that of ion selectivity. The results also shows that Chabazite is effective for the adsorption of Cs ion, and Zeolite-A and Zeolite-13X for that of Sr and Co ions.