scholarly journals Diffusion of CH4 and N2 in Barium-Exchanged Reduced Pore Zorite (Ba-RPZ) and Zeolite 4A

2021 ◽  
Author(s):  
Nicholas S. Wilkins ◽  
James A. Sawada ◽  
Arvind Rajendran
Keyword(s):  
Adsorption Equilibrium ◽  
Diffusion Constant ◽  
Micropore Diffusion ◽  
Complex Diffusion ◽  
Zeolite 4A ◽  
Resistance Model ◽  
Equilibrium Data ◽  
Barrier Resistance ◽  
The One ◽  
Adsorption Equilibrium Data

<pre><p>Barium-exchanged reduced pore zorite (Ba-RPZ) is a titanosilicate molecular sieve that is able to separate CH4 from N2 based on their relative molecular sizes. A detailed study of N2 and CH4 adsorption equilibrium and diffusion on Ba-RPZ was completed using low and high-pressure volumetry. Adsorption equilibrium data for Ba-RPZ from limiting vacuum to 1.2 bar were measured at 30, 40, and 50° C for CH4 and at 30, 50, and 70° C for N2. Constant volume uptake experiments were conducted to estimate the diffusivities of CH4 at 30, 40, and 50° C and N2 -20, -10, and 0° C. Similar experiments were carried out with zeolite 4A to validate the methods used in this study. On the one hand, the transport of N2 in Ba-RPZ was found to be controlled by diffusion in the micropores. On the other hand, the transport of CH4 in Ba-RPZ was described by a dual-resistance model, including a barrier resistance and micropore diffusional resistance. Both the barrier and micropore diffusion coefficients demonstrated concentration dependence. While the micropore diffusion constant followed Darken's relationship, the barrier resistance did not. A concentration-dependent dual-resistance diffusion model for methane was constructed and validated using experimental data across a range of pressures and temperatures. The concentration-dependent dual-resistance model was able to describe the complex diffusion behaviour methane displays as it progressed from the dual-resistance controlled region to the micropore-controlled region of the isotherm. The calculated CH4/N2 kinetic selectivity of Ba-RPZ was shown to be significantly larger than the current benchmark material for CH4/N2 separation.</p></pre>

scholarly journals Diffusion of CH4 and N2 in Barium-Exchanged Reduced Pore Zorite (Ba-RPZ) and Zeolite 4A

2021 ◽  
Author(s):  
Nicholas S. Wilkins ◽  
James A. Sawada ◽  
Arvind Rajendran
Keyword(s):  
Adsorption Equilibrium ◽  
Diffusion Constant ◽  
Micropore Diffusion ◽  
Complex Diffusion ◽  
Zeolite 4A ◽  
Resistance Model ◽  
Equilibrium Data ◽  
Barrier Resistance ◽  
The One ◽  
Adsorption Equilibrium Data

<pre><p>Barium-exchanged reduced pore zorite (Ba-RPZ) is a titanosilicate molecular sieve that is able to separate CH4 from N2 based on their relative molecular sizes. A detailed study of N2 and CH4 adsorption equilibrium and diffusion on Ba-RPZ was completed using low and high-pressure volumetry. Adsorption equilibrium data for Ba-RPZ from limiting vacuum to 1.2 bar were measured at 30, 40, and 50° C for CH4 and at 30, 50, and 70° C for N2. Constant volume uptake experiments were conducted to estimate the diffusivities of CH4 at 30, 40, and 50° C and N2 -20, -10, and 0° C. Similar experiments were carried out with zeolite 4A to validate the methods used in this study. On the one hand, the transport of N2 in Ba-RPZ was found to be controlled by diffusion in the micropores. On the other hand, the transport of CH4 in Ba-RPZ was described by a dual-resistance model, including a barrier resistance and micropore diffusional resistance. Both the barrier and micropore diffusion coefficients demonstrated concentration dependence. While the micropore diffusion constant followed Darken's relationship, the barrier resistance did not. A concentration-dependent dual-resistance diffusion model for methane was constructed and validated using experimental data across a range of pressures and temperatures. The concentration-dependent dual-resistance model was able to describe the complex diffusion behaviour methane displays as it progressed from the dual-resistance controlled region to the micropore-controlled region of the isotherm. The calculated CH4/N2 kinetic selectivity of Ba-RPZ was shown to be significantly larger than the current benchmark material for CH4/N2 separation.</p></pre>

scholarly journals Diffusion of CH4 and N2 in Barium-Exchanged Reduced Pore Zorite (Ba-RPZ) and Zeolite 4A

2021 ◽  
Author(s):  
Nicholas S. Wilkins ◽  
James A. Sawada ◽  
Arvind Rajendran
Keyword(s):  
Adsorption Equilibrium ◽  
Diffusion Constant ◽  
Micropore Diffusion ◽  
Complex Diffusion ◽  
Zeolite 4A ◽  
Resistance Model ◽  
Equilibrium Data ◽  
Barrier Resistance ◽  
The One ◽  
Adsorption Equilibrium Data

<pre><p>Barium-exchanged reduced pore zorite (Ba-RPZ) is a titanosilicate molecular sieve that is able to separate CH4 from N2 based on their relative molecular sizes. A detailed study of N2 and CH4 adsorption equilibrium and diffusion on Ba-RPZ was completed using low and high-pressure volumetry. Adsorption equilibrium data for Ba-RPZ from limiting vacuum to 1.2 bar were measured at 30, 40, and 50° C for CH4 and at 30, 50, and 70° C for N2. Constant volume uptake experiments were conducted to estimate the diffusivities of CH4 at 30, 40, and 50° C and N2 -20, -10, and 0° C. Similar experiments were carried out with zeolite 4A to validate the methods used in this study. On the one hand, the transport of N2 in Ba-RPZ was found to be controlled by diffusion in the micropores. On the other hand, the transport of CH4 in Ba-RPZ was described by a dual-resistance model, including a barrier resistance and micropore diffusional resistance. Both the barrier and micropore diffusion coefficients demonstrated concentration dependence. While the micropore diffusion constant followed Darken's relationship, the barrier resistance did not. A concentration-dependent dual-resistance diffusion model for methane was constructed and validated using experimental data across a range of pressures and temperatures. The concentration-dependent dual-resistance model was able to describe the complex diffusion behaviour methane displays as it progressed from the dual-resistance controlled region to the micropore-controlled region of the isotherm. The calculated CH4/N2 kinetic selectivity of Ba-RPZ was shown to be significantly larger than the current benchmark material for CH4/N2 separation.</p></pre>

scholarly journals CORRELATION OF ADSORPTION EQUILIBRIUM DATA OF VARIOUS GASES AND VAPORS ON MOLECULAR-SIEVING CARBON

1974 ◽  
Vol 7 (3) ◽  
pp. 158-162 ◽  
Author(s):  
KUNITARO KAWAZOE ◽  
TOSHINAGA KAWAI ◽  
YOSHITOMO EGUCHI ◽  
KIYOSHI ITOGA
Keyword(s):  
Adsorption Equilibrium ◽  
Equilibrium Data ◽  
Adsorption Equilibrium Data ◽  
Molecular Sieving

scholarly journals Modified Dual-Site Langmuir Adsorption Equilibrium Models from A GCMC Molecular Simulation

2020 ◽  
Vol 10 (4) ◽  
pp. 1311
Author(s):  
Junchao Wang ◽  
Yongjie Wei ◽  
Zhengfei Ma
Keyword(s):  
Molecular Simulation ◽  
Adsorption Energy ◽  
Pressure Swing Adsorption ◽  
Adsorption Equilibrium ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Adsorption Energies ◽  
Pressure Swing ◽  
Adsorption Equilibrium Data ◽  
Dual Site

In the modern industrial separation process, the pressure swing adsorption technology is widely used to separate and purify gases due to its low energy consumption, low cost, convenience, reliability, and environmental benignity. The basic elements of the design and application of the pressure swing adsorption process are adsorption isotherms at different temperatures for adsorbents. The dual-site Langmuir (DSL) adsorption equilibrium model is the mostly used model; however, this model is based on the assumption that the adsorption energy on the surface of an adsorbent is uniform and remains unchanged. Here, a grand canonical Monte Carlo (GCMC) molecular simulation was used to calculate the CO2 adsorption equilibrium on MIL-101 (Cr) at 298 K. MIL-101 (Cr) was chosen, as it has more a general pore structure with three different pores. The calculation results showed that the adsorption energies with different adsorption pressures fitted a normal distribution and the relationship of the average adsorption energies, E with pressures had a linear form described as: E = aP + c. With this relationship, the parameter b = k·exp(E/RT) in the DSL model was modified to b = k·exp((aP + c)/RT), and the modified DSL model (M-DSL) was used to correlate the adsorption equilibrium data on CO2-MIL-101 (Cr), C2H4-HHPAC, CH4-BPL, and CO2-H-Mordenite, showing better correlations than those of the DSL model. We also extended the parameter qm in the M-DSL model with the equation qm = k1 + k2T to adsorption equilibrium data for different temperatures. The obtained model (M-TDSL) was checked with the abovementioned adsorption equilibrium systems. The fitting results also indicated that the M-TDSL model could be used to improve the correlation of adsorption equilibrium data for different temperatures. The linear relationship between the average adsorption energy and adsorption pressure could be further tested in other adsorption equilibrium models to determine its universality.

scholarly journals Evaluation of Adsorption Equilibrium Models by Means of Data Obtained for Oxygen and Nitrogen on Zeolite 5A

1988 ◽  
Vol 5 (3) ◽  
pp. 199-212
Author(s):  
Xuanqiang Yu ◽  
Shuguang Deng ◽  
Pingdong Wu
Keyword(s):  
Adsorption Equilibrium ◽  
Statistical Thermodynamic ◽  
Solution Theory ◽  
Elevated Pressures ◽  
Adsorption Equilibria ◽  
Ideal Adsorbed Solution Theory ◽  
Regression Parameters ◽  
Equilibrium Data ◽  
Adsorbed Solution ◽  
Adsorption Equilibrium Data

Both fugacity and the Lewis–Randall fugacity rule have been incorporated in the vacancy solution and ideal adsorbed solution theories, and in a simplified statistical thermodynamic model, to allow these various approaches to predict adsorption equilibria at elevated pressures. Adsorption equilibrium data for oxygen and nitrogen determined at 273.15, 293.15 and 313.15 K at pressures up to 60 atm have been compared with the values calculated from these models using regression parameters obtained from adsorption isotherms for the pure components. Of these various models, the vacancy solution theory with the Wilson equation and the ideal adsorbed solution theory provided the closest prediction to the experimental data.

scholarly journals Adsorption isotherm and thermodynamic studies of As(III) removal from aqueous solutions using used cigarette filter ash

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Pezhman Zein Al-Salehin ◽  
Farid Moeinpour ◽  
Fatemeh S. Mohseni-Shahri
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Isotherm ◽  
Adsorption Equilibrium ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Cigarette Filter ◽  
Electron Microscopy Analysis ◽  
Equilibrium Data ◽  
Thermodynamic Variables ◽  
Adsorption Equilibrium Data

Abstract In the present paper, used cigarette filter ash was prepared and used as an active adsorbent to remove As(III) ions from aqueous solutions. The prepared adsorbent structure was identified by scanning electron microscopy analysis, Brunauer–Emmett–Teller method and energy-dispersive X-ray spectroscopy analysis. The influence of contact time, pH, adsorbent dose and initial concentration of As(III) on the removal of As(III) was assessed. Several isotherm models were checked to illustrate the adsorption equilibrium. The adsorption equilibrium data adapted well with the Langmuir isotherm model. The maximum adsorption capacity of 33.33 mg/g was acquired from the Langmuir isotherm. The calculated thermodynamic variables verified that the adsorption process is spontaneous and endothermic.

Determination of the adsorbate density from supercritical gas adsorption equilibrium data

Carbon ◽  
2003 ◽  
Vol 41 (3) ◽  
pp. 585-588 ◽  
Author(s):  
Li Ming ◽  
Gu Anzhong ◽  
Lu Xuesheng ◽  
Wang Rongshun
Keyword(s):  
Gas Adsorption ◽  
Adsorption Equilibrium ◽  
Equilibrium Data ◽  
Adsorption Equilibrium Data

Adsorption Equilibrium and Kinetics of Copper from Aqueous Solutions on Steel Slag

2011 ◽  
Vol 354-355 ◽  
pp. 33-36
Author(s):  
Jian Yun Li ◽  
Quan Xian Hua ◽  
Jun Ling Niu ◽  
Jian Wei Tang ◽  
Ke Xu
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Equilibrium ◽  
Steel Slag ◽  
Adsorption Rate ◽  
Batch Adsorption ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorption Equilibrium Data ◽  
Kinetics Of

The adsorption of copper in aqueous solutions by steel slag was studied in batch adsorption experiments. The adsorption equilibrium data fitted best with Langmuir and Freundlich equations. The adsorption was preferential type. A comparison of the kinetics models on the apparent adsorption rate showed that the adsorption system was best described by the pseudo-second-order kinetics. The adsorption rate was controlled by both liquid film diffusion and intraparticle dispersion.

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