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 Influence of Carbon Uniformity on Its Characteristics and Adsorption Capacities of CO2 and CH4 Gases

2020 ◽  
Vol 11 (1) ◽  
pp. 265
Author(s):  
Ahmed Awadallah-F ◽  
Shaheen A. Al-Muhtaseb
Keyword(s):  
Activated Carbons ◽  
Multiwall Carbon Nanotubes ◽  
Mixed Gas ◽  
Resorcinol Formaldehyde ◽  
Binary Gas Mixture ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Adsorption Equilibrium Data ◽  
Multiwall Carbon ◽  
Dual Site

Activated carbons of resorcinol-formaldehyde aerogels (AC-RFA) were prepared and mixed with multiwall carbon nanotubes (MWCNTs) with various ratios. Samples were characterized by different techniques. The novelty of the study is in evaluating the effect of uniformity of carbon nanocomposites on their performance for the adsorption of CH4 and CO2 gases as well predicting the separation of their mixtures. The results indicated that, by increasing the percentage of MWCNTs into the sample, its structural uniformity and order ascend. The capacities of CH4 and CO2 by adsorption were measured at various temperatures, and were correlated with the extended dual site Langmuir (DSL) model. Overall, results showed that the adsorption capacity of MWCNTs towards gases is relatively very low compared to that of activated carbons. The DSL model was utilized to forecast the separation of the binary CO2/CH4 mixed gas based on knowledge of single component adsorption isotherm parameters. Adsorption equilibrium data of the CO2/CH4 binary gas mixture was forecasted at different temperatures by DSL model in accordance with the perfect-negative (PN) or perfect-positive (PP) behaviors on the heterogeneous surface of the adsorbent.

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

Preparation of Al2O3 Whiskers from AACH Using Hydrothermal Method and its Use for the Removal of Lead Ions by Adsorption

2021 ◽  
Vol 875 ◽  
pp. 177-183
Author(s):  
Asma Ameer ◽  
Syed Mujtaba Ul Hassan ◽  
Syed M. Husnain ◽  
Jamil Ahmad ◽  
Faisal Shahzad ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Heavy Ion ◽  
Lead Ions ◽  
Hydrothermal Route ◽  
Adsorption Parameters ◽  
Ion Removal ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Adsorption Equilibrium Data

This work explores the potential of adsorption of Pb2+ by hydrothermally synthesized alumina. In comparison to other heavy ion removal techniques, adsorption is preferred in the current study as it has the edge of ease of operation and environment friendly characteristics. Synthesis of high surface area alumina whiskers was achieved by hydrothermal route which were subsequently employed for the active adsorption of lead ions. AACH (Ammonium Aluminum Carbonate Hydroxide), used as precursor for alumina, was calcined at three different temperatures i.e. 700, 900 and 1100 °C to form alumina whiskers. These whiskers were characterized by XRD, SEM, BET and FTIR. Various adsorption parameters such as contact time, pH, initial metal concentration were studied for lead ions. Maximal removal efficiency was obtained for the specimen having pH 4 and calcined at 700 °C for 60 minutes. Kinetic data was best described by pseudo second order model, whereas the adsorption equilibrium data obeyed the Langmuir adsorption isotherm model.

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.

MICROWAVE ASSISTED K2CO3 PALM SHELL ACTIVATED CARBON AS SORBENT FOR CO2 ADSORPTION APPLICATION

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Usman Dadum Hamza ◽  
Noor Shawal Nasri ◽  
Nor Aishah Saidina Amin ◽  
Jibril Mohammed ◽  
Husna Mohd Zain
Keyword(s):  
Activated Carbon ◽  
Porous Carbon ◽  
Co2 Adsorption ◽  
Co2 Uptake ◽  
Adsorption Method ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Co2 Adsorption Capacity ◽  
Adsorption Equilibrium Data ◽  
Best Fit

Carbon dioxide is believed to be a major greenhouse gas (GHG) that contributes to global warming. In this study, palm shells were used as a precursor to prepare CO2 activated carbon sorbents via carbonization, chemical impregnation with K2CO3 and microwave activation.  Adsorption equilibrium data for CO2 adsorption on the porous carbon were obtained at different temperatures using static volumetric adsorption method. Langmuir, Freundlich, Sips and Toths models were used to correlate the experimental data. The CO2 adsorption capacity at 303.15, 343.15, 378.15 443.15 K and 1 bar on the sorbent was 2.71, 1.5, 0.77, 0.69 mmol/g respectively. Sips isotherm was found to have the best fit. The results indicated that the porous carbon sorbent prepared by carbonization and microwave K2CO3 assisted activation have good CO2 uptake. The porous carbons produced are therefore good candidates for CO2 adsorption applications

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
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