Application of a radial diffusion model to describe gas/particle sorption kinetics

1990 ◽  
Vol 24 (9) ◽  
pp. 1378-1386 ◽  
Author(s):  
Stewart A. Rounds ◽  
James F. Pankow
Keyword(s):  
Diffusion Model ◽  
Sorption Kinetics ◽  
Radial Diffusion

scholarly journals Radial diffusion modeling with empirical lifetimes: comparison with CRRES observations

2005 ◽  
Vol 23 (4) ◽  
pp. 1467-1471 ◽  
Author(s):  
Y. Y. Shprits ◽  
R. M. Thorne ◽  
G. D. Reeves ◽  
R. Friedel
Keyword(s):  
Diffusion Model ◽  
Radiation Effects ◽  
Outer Zone ◽  
Recovery Phase ◽  
Decay Rates ◽  
Radial Diffusion ◽  
Main Phase ◽  
Relativistic Electrons ◽  
Storm Main Phase ◽  
Order Of Magnitude

Abstract. A time dependent radial diffusion model is used to quantify the competing effects of inward radial diffusion and losses on the distribution of the outer zone relativistic electrons. The rate of radial diffusion is parameterized by Kp with the loss time as an adjustable parameter. Comparison with HEEF data taken over 500 Combined Release and Radiation Effects Satellite (CRRES) orbits indicates that 1-MeV electron lifetimes near the peak of the outer zone are less than a day during the storm main phase and few days under less disturbed conditions. These values are comparable to independent estimates of the storm time loss rate due to scattering by EMIC waves and chorus emission, and also provide an acceptable representation of electron decay rates following the storm time injection. Although our radial diffusion model, with data derived lifetimes, is able to simulate many features of the variability of outer zone fluxes and predicts fluxes within one order of magnitude accuracy for most of the storms and L values, it fails to reproduce the magnitude of flux changes and the gradual build up of fluxes observed during the recovery phase of many storms. To address these differences future modeling should include an additional local acceleration source and also attempt to simulate the pronounced loss of electrons during the main phase of certain storms.

scholarly journals Extended Rate Constants Distribution (RCD) Model for Sorption in Heterogeneous Systems: 2. Importance of Diffusion Limitations for Sorption Kinetics on Cryogels in Batch

Gels ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 15 ◽  
Author(s):  
Irina Malakhova ◽  
Alexey Golikov ◽  
Yuliya Azarova ◽  
Svetlana Bratskaya
Keyword(s):  
Kinetic Parameters ◽  
Diffusion Model ◽  
Residence Time ◽  
Rate Constants ◽  
Heterogeneous Systems ◽  
Sorption Kinetics ◽  
Sorption Rate ◽  
Kinetic Curves ◽  
Dynamic Conditions ◽  
Diffusion Limitations

Here we address the problem of what we can expect from investigations of sorption kinetics on cryogel beads in batch. Does macroporosity of beads indeed help eliminate diffusion limitations under static sorption conditions? Are sorption rate constants calculated using phenomenological kinetic models helpful for predicting sorption properties under dynamic conditions? Applying the rate constants distribution (RCD) model to kinetic curves of Cu(II) ions sorption on polyethyleneimine (PEI) cryogel and gel beads and fines, we have shown that diffusion limitations in highly swollen beads are very important and result in at least ten-fold underestimation of the sorption rate constants. To account for intraparticle diffusion, we have developed the RCD-diffusion model, which yields “intrinsic” kinetic parameters for the sorbents, even if diffusion limitations were important in kinetic experiments. We have shown that introduction of a new variable—characteristic diffusion time—to the RCD model significantly improved the reliability of sorption kinetic parameters and allowed prediction of the minimal residence time in column required for efficient uptake of the adsorbate under dynamic conditions. The minimal residence time determined from kinetic curves simulated using the RCD-diffusion model was in good agreement with experimental data on breakthrough curves of Cu(II) ion sorption on monolith PEI cryogel at different flow rates.

scholarly journals Reanalysis of relativistic radiation belt electron fluxes using CRRES satellite data, a radial diffusion model, and a Kalman filter

2007 ◽  
Vol 112 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
Yuri Shprits ◽  
Dmitri Kondrashov ◽  
Yue Chen ◽  
Richard Thorne ◽  
Michael Ghil ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Diffusion Model ◽  
Satellite Data ◽  
Radiation Belt ◽  
Radial Diffusion

scholarly journals Radial diffusion model for fragrance materials: prediction and validation

AIChE Journal ◽  
2021 ◽  
Author(s):  
Rafael N. Almeida ◽  
Alírio E. Rodrigues ◽  
Rubem M. F. Vargas ◽  
Eduardo Cassel
Keyword(s):  
Diffusion Model ◽  
Radial Diffusion ◽  
Fragrance Materials

General radial diffusion model for heterogeneous sorbents

1999 ◽  
Vol 18 (8) ◽  
pp. 1694-1700 ◽  
Author(s):  
Edward C. Heyse ◽  
Daniel J. Mika ◽  
Thomas P. De Venoge ◽  
David L. Coulliette ◽  
Audrey McGowin
Keyword(s):  
Diffusion Model ◽  
Radial Diffusion

scholarly journals Approximation of a radial diffusion model with a multiple-rate model for hetero-disperse particle mixtures

2008 ◽  
Vol 97 (1-2) ◽  
pp. 55-66 ◽  
Author(s):  
Arash Massoudieh ◽  
Daeyoung Ju ◽  
Thomas M. Young ◽  
Timothy R. Ginn
Keyword(s):  
Diffusion Model ◽  
Disperse Particle ◽  
Radial Diffusion ◽  
Rate Model
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