Chihara, Kazuyuki

Saito, Kenta

Teramura, Yuki

Tomita, Shinji

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 0 200 400 600 800 1000Time after impluse [sec]Concentration90 Ž120 Ž150 Ž180 ŽMomentanalysis 0.010 0.100 1.000 10.000 0.0017 0.0022 0.0027 0.0032 K*M/RT [1/atm]1/T [1/K]DCM [USY-6.18]DCM [PQ-USY]DCM [HSZ-390HUD]DCM [Na-Y]DCM [Pentasil-1]DCM [Pentasil-2]1.E-111.E-101.E-091.E-081.E-071.E-061.E-050.0017 0.0022 0.0027 0.0032 D [cm2/sec]1/T [1/K]DCM [USY-6.18]DCM [PQ-USY]DCM [HSZ-390HUD]DCM [Na-Y]DCM [Pentasil-1]DCM [Pentasil-2]Fig.3 Typical Arrhenius’ Plot Fig.1 Typical chromatographic peaks Adsorbate:chloroform[TCM] Adsorbent:Y-type zeolite[HSZ-390HUD]  Fig.2 Typical Van’t Hoff Plot  Diffusion of Chlorinated Hydrocarbons in High Silica Zeolite - Comparison Between Chromatographic Data and Molecular Dynamic Simulation Kazuyuki Chihara, Yuki Teramura, Shinji Tomita, Kenta Saito Department of Applied Chemistry, Meiji University, 1-1-1 Higashi-mita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan, E-mail:chihara@isc.meiji.ac.jp 1. Introduction In this study, we investigated diffusion of chlorinated hydrocarbons in high silica zeolite by chromatographic method and molecular dynamics simulation.                 Adsorption measurement of various chlorinated hydrocarbons on FAU-type and MFI-type zeolites were performed using the chromatographic method to examine the adsorption phenomena. Dichloromethane (DCM), chloroform (TCM), trichloroethylene (TCE), and tetrachloroethylene (PCE), were used as adsorbate, and HSZ-390HUD, PQ-USY, USY-6.18, Na-Y, Pentasile-2 and Pentacile-1 were used as adsorbent. By introducing the concentration pulse of adsorbate to the carrier gas stream at the inlet of the adsorbent column, the concentration elution curve at the outlet of the column was measured. Chromatographic peaks were analyzed by moment analysis equation. Van’t Hoff plot and Arrhenius’ plot were drawn with the use of adsorption equilibrium constant K* and micropore diffusivity D.                    The Open-Access Journal for the Basic Principles of Diffusion Theory, Experiment and Application © 2009, K. Chiharadiffusion-fundamentals.org 11 (2009) 24, pp 1-2 30 35 40 45 50 55 60 65 70 Isosteric heat of adsorption , q st[kJ/mol]Heat of vaporization ,  Δ H [kJ/mol] Pentasil-2Pentasil-1Na-YUSY-6.18PQ-USYHSZ-390HUDslope = 120 4030Fig. 4 Correlation of isosteric heat of adsorption with heat of vaporization Pentasil-2Pentasil-1Na-YUSY-6.18PQ-USYHSZ-390HUD30 50 7040 601020806040100120Activation energy of diffusion in micropore , E [kJ/mol]Isosteric heat of adsorption , qst[kJ/mol]Fig. 5 Correlation of activation energy of micropore diffusion with isosteric heat of adsorption Fig. 6 Dynamic behavior of TCM in FAU-type zeolite at 423 K 2. Result and Discussion                                                                                      Isosteric heat of adsorption qst and activation energy in micropore diffusion E were determined by the slope. The amount adsorbed and isosteric heats of adsorption became low, when SiO2/Al2O3 ratio of zeolite became high. The isosteric heats of adsorption were roughly 1.4 to 2.0 of the heats of vaporization. The activation energies of diffusion in the micropore of zeolite were found to be almost 130 % to 150 % of the isosteric heats of adsorption. Figs. 4 and 5 show “Correlation of Isosteric Heat of Adsorption with Heat of Vaporization” and “Correlation of activation energy of the micropore diffusion with isosteric heat of adsorption”.                3. Conclusion In addition Molecular Dynamics (MD) simulations for diffusion of the chlorinated hydrocarbons in the zeolites were performed using the Accelrys® MATERIALS STUDIO 4.3 simulation package. Self-diffusion coefficients were calculated from Mean Square Displacement (MSD) using the Einstein equations. The computed results were also compared with the experimental data.         0 ps                                          100 ps                                           200 ps   

Diffusion of chlorinated hydrocarbons in high silica zeolite - comparison between chromatographic data and molecular dynamic simulation

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Diffusion of chlorinated hydrocarbons in high silica zeolite - comparison between chromatographic data and molecular dynamic simulation

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