scholarly journals Study of the hydrogen physisorption on adsorbents based on activated carbon by means of statistical physics formalism: modeling analysis and thermodynamics investigation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Manel Ben Yahia ◽  
Sarra Wjihi
Keyword(s):  
Activated Carbon ◽  
Statistical Physics ◽  
Adsorption Process ◽  
Hydrogen Adsorption ◽  
Physical Nature ◽  
Hydrogen Uptake ◽  
Sorption Process ◽  
Hydrogen Molecules ◽  
Physico Chemical ◽  
Suitable Framework

Abstract An advanced statistical physics model has been applied to study the hydrogen adsorption isotherm on two modified types of activated carbon, namely granular coal activated carbon (AC (GC)) and coconut shell activated carbon (AC (CS)). This model is established with the statistical physics approach. It is a more general model including various parameters having a defined physico-chemical sense which were discussed at different temperatures. Hence new physic-chemical interpretations of the adsorption process of hydrogen are provided. The analysis of the hydrogen uptake capacities at saturation showed that the AC (GC) adsorbent displayed a high adsorption capacity (3.21 mg/g). This due to the contribution of the number of hydrogen molecules per site (1.27) associated with the receptor sites density (0.74 mg/g) and the number of formed layers (3.42). The modeling results suggested that the hydrogen adsorption occurred by non-parallel positions on the two tested adsorbents thus evincing that the adsorption cannot be other than a multi-molecular process. The calculated adsorption energies globally varied from 7.01 to 12.92 kJ/mol, confirming the physical nature of the adsorption process for both studied systems. The thermodynamic functions, namely internal energy, enthalpy and entropy were estimated to better analyze the hydrogen sorption process. In summary, the statistical physics analysis provided reliable concrete physico-chemical interpretations of hydrogen adsorption process on carbon-based adsorbents with various microstructures to develop a storage compounds with a suitable framework for a hydrogen storage structure.

scholarly journals Modeling the removal of Reactive Red 120 dye from aqueous effluents by activated carbon

2020 ◽  
Vol 82 (4) ◽  
pp. 651-662
Author(s):  
Kods Oueslati ◽  
Eder C. Lima ◽  
Fakher Ayachi ◽  
Mariene R. Cunha ◽  
Abdelmottaleb Ben Lamine
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherms ◽  
Statistical Physics ◽  
Adsorption Process ◽  
Dye Adsorption ◽  
Physical Nature ◽  
Experimental Conditions ◽  
Reactive Red 120 ◽  
Receptor Sites ◽  
Aqueous Effluents

Abstract The adsorption isotherms of Reactive Red 120 (RR-120) on Brazilian pine-fruit shell activated carbon, at six temperatures (298, 303, 308, 313, 318 and 323 K) and pH = 6, were determined and interpreted using a double layer model with one energy. A statistical physics treatment established the formulation of this model. Steric and energetic parameters related to the adsorption process, such as the number of adsorbed molecules per site, the receptor sites density and the concentration at half-saturation, have been considered. Thermodynamic potential functions such as entropy, internal energy and Gibbs free enthalpy are analyzed, and the choice of the models is based on assumptions in correlation with experimental conditions. By numerical fitting, the investigated parameters were deduced. The theoretical expressions provide a good understanding and interpretation of the adsorption isotherms at the microscopic level. We believe that our work contributes to new theoretical insights on the dye adsorption in order to know the physical nature of the adsorption process.

Molecular Simulation Study on Catenation Effects on Hydrogen Uptake Capacity of MOFs

2006 ◽  
Vol 971 ◽  
Author(s):  
Dong Hyun Jung ◽  
Tae Bum Lee ◽  
Daejin Kim ◽  
Kangsung Park ◽  
Jaheon Kim ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Force Field ◽  
Molecular Dynamics Simulations ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Adsorbed Hydrogen ◽  
Hydrogen Molecules ◽  
Metal Organic ◽  
Dynamics Simulations ◽  
Gcmc Simulations

ABSTRACTIn order to investigate the reason for the higher capacity of the interpenetrating isoreticular metal-organic frameworks (IRMOFs) at lower temperatures, we performed grand canonical Monte Carlo (GCMC) simulations and molecular dynamics simulations at 77 K for a set of the interpenetrating IRMOF-11 and the non-interpenetrating counterpart IRMOF-12. From the GCMC simulations, we found universal force field (UFF) is better for describing the hydrogen adsorption behavior than DREIDING force field. The results from the molecular dynamics simulations showed the density of adsorbed hydrogen molecules was increased in the various pores created by the catenation of IRMOF comparing to that of the pores in IRMOF-12. Moreover, the adsorbed hydrogen molecules in IRMOF-11 have the smaller diffusion coefficients. It means that their dynamic behavior is more restricted because of the complexity of the interpenetrating network of IRMOF-11. These results of molecular simulations show the small pores created by the catenation are important for the increase of hydrogen adsorption on IRMOF-11 at lower temperatures.

Hydrogen Storage in Carbon Nanoscrolls: A Molecular Dynamics Study

2005 ◽  
Vol 885 ◽  
Author(s):  
Vitor Coluci ◽  
Scheila F. Braga ◽  
Ray H. Baughman ◽  
Douglas S. Galvão
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Internal Cavity ◽  
Multiwalled Carbon ◽  
Graphene Layers ◽  
Hydrogen Molecules ◽  
Carbon Nanoscrolls ◽  
Dynamics Simulations ◽  
Uptake Mechanisms

ABSTRACTWe carried out molecular dynamics simulations with Tersoff-Brenner potentials in order to investigate the hydrogen uptake mechanisms and storage capacity of carbon nanoscrolls (CNSs). CNSs are jelly roll-like structures formed by wrapping graphene layers. Interlayer adsorption is an option for this material, which does not exist for single and multiwalled carbon nanotubes. We analyzed the processes of hydrogen physisorption and uptake mechanisms. We observed incorporation of hydrogen molecules in both external and internal scroll surfaces. Insertion in the internal cavity and between the scroll layers is responsible for 40% of the total hydrogen adsorption at 77 K.

Energetic investigation of the adsorption process of CH4, C2H6 and N2 on activated carbon: Numerical and statistical physics treatment

2014 ◽  
Vol 433 ◽  
pp. 55-61 ◽  
Author(s):  
Yosra Ben Torkia ◽  
Manel Ben Yahia ◽  
Mohamed Khalfaoui ◽  
Shaheen A. Al-Muhtaseb ◽  
Abdelmottaleb Ben Lamine
Keyword(s):  
Activated Carbon ◽  
Statistical Physics ◽  
Adsorption Process

scholarly journals Activated Olive Stones as a Low-Cost and Environmentally Friendly Adsorbent for Removing Cephalosporin C from Aqueous Solutions

2021 ◽  
Vol 18 (9) ◽  
pp. 4489
Author(s):  
Gerardo León ◽  
Francisco Saura ◽  
Asunción María Hidalgo ◽  
Beatriz Miguel
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Adsorption Process ◽  
Low Cost ◽  
Physical Nature ◽  
Freundlich Isotherm ◽  
Mass Transfer Process ◽  
Order Kinetic ◽  
Cephalosporin C ◽  
Olive Stones

In this paper, we describe the removal of cephalosporin C (CPC) from aqueous solutions by adsorption onto activated olive stones (AOS) in a stirred tank. For comparative purposes, several experiments of adsorption onto commercial granular activated carbon were carried out. A quantum study of the different species of cephalosporin C that, depending on the pH, exist in aqueous solution pointed to a favorable mass transfer process during adsorption. Activated olive stones were characterized by SEM, EDX and IR techniques and their pHzc was determined. A 10−3 M HCl cephalosporin C solution has been selected for the adsorption experiments because at the pH of that solution both electrostatic and hydrogen bond interactions are expected to be established between the adsorbate and the adsorbent. The adsorption process is best described by the Freundlich isotherm model and the pseudo-second-order kinetic model, while the adsorption mechanism is mainly controlled by film diffusion. Under the conditions studied, the adsorption process is of a physical nature, endothermic and spontaneous. Comparison of the adsorption results obtained in this paper with those of other authors shows that the efficiency of AOS is 20% of that of activated carbon but 65% higher than that of the XAD-2 adsorbent. Considering its low price, abundance, easy accessibility and eco-compatibility, the use of activated olive stones as adsorbents for the removal of emerging pollutants from aqueous solutions represents an interesting possibility from both the economic and the environmental points of view.

Grand Canonical Monte Carlo Simulations for the Prediction of Adsorption Capacity of Hydrogen in MOFs

2007 ◽  
Vol 124-126 ◽  
pp. 1693-1696 ◽  
Author(s):  
Dong Hyun Jung ◽  
Dae Jin Kim ◽  
Tae Bum Lee ◽  
Ja Heon Kim ◽  
Seung Hoon Choi
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Rational Design ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Grand Canonical Monte Carlo ◽  
Diverse Range ◽  
Adsorption Sites ◽  
Hydrogen Molecules ◽  
Grand Canonical

We performed grand canonical Monte Carlo simulations on the series of MOFs, that are Metal-Organic Frameworks having various organic linkers and nanocube frameworks, to find out rational design and synthetic strategies toward efficient hydrogen storage materials. The adsorption amounts of hydrogen molecules showed diverse range according to the variation of parameter values. This indicated that the hydrogen adsorption was sensitive to the values of parameters corresponding to the non-bonding interactions. The optimization of the parameters was done to fit the experimental results at 77 K. After the parameterization of the potential function, we adopted this condition to predict the adsorption amount of hydrogen molecules on IRMOF-3, which has NH2 group as the substituent of hydrogen bonded to benzene ring. The calculation results showed good agreement with experimental adsorptions and we analyzed the adsorption sites of each MOF and the relationship between the adsorption characteristics and the hydrogen uptake capacity.

scholarly journals Removal of Pb(II), Fe(II) and Zn(II) using activated carbon produced from foxtail palm fruit chemically activated by KOH and H3PO4.

2019 ◽  
Vol 7 (1) ◽  
pp. 19-22
Author(s):  
Nur Sabiha Sairan ◽  
Noor Syuhadah Subki ◽  
Nik Raihan Nik Yusoff
Keyword(s):  
Heavy Metal ◽  
Activated Carbon ◽  
Phosphoric Acid ◽  
Potassium Hydroxide ◽  
Adsorption Process ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Sorption Process ◽  
Palm Fruit ◽  
Main Factor

The increasing rate of urbanization and continuous developments are the main factor which led to heavy metals contamination into the environment especially in the water bodies. However, the contamination of heavy metal can be treated using adsorption process using activated carbon. Thus, this study was based on using powdered activated carbon, which prepared from foxtail palm fruit and chemically activated using potassium hydroxide and phosphoric acid. The main parameters such as effect of chemical activating agent, effect of initial concentration of heavy metal and effect of sorbent dosage that influenced the sorption process were studied. From the result, activated carbon that was chemically activated by phosphoric acid shown the best removal compared to activated carbon that was chemically activated by potassium hydroxide. The percentage removal of Pb(II), Fe(II) and Zn(II) were 95.8%, 99.9% and 22.8% respectively using 0.5 g of activate carbon. The result indicates that the adsorption process using activated carbon that produced from plant can be applied for heavy metal removal from aqueous solution.

scholarly journals Hydrogen Storage in Iron/Carbon Nanopowder Composite Materials: Effect of Varying Spiked Iron Content on Hydrogen Adsorption

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chun-Lin Chu ◽  
Chia-Feng Chang ◽  
Jiann-Ruey Chen ◽  
Yiin-Kuen Fuh
Keyword(s):  
Composite Materials ◽  
Hydrogen Storage ◽  
Iron Content ◽  
Storage Capacity ◽  
Hydrogen Adsorption ◽  
Hydrogen Uptake ◽  
Uptake Capacity ◽  
Hydrogen Storage Capacity ◽  
Surface Areas ◽  
Hydrogen Molecules

This study investigates the effects of varying the spiked iron content of iron/carbon nanopowder (Fe/CNP) composite materials on hydrogen storage capacity. Among four such samples, a maximum hydrogen uptake of approximately 0.48 wt% was obtained with 14 wt% of spiked iron under 37 atm and 300 K. This higher hydrogen uptake capacity was believed to be closely related to the physisorption mechanism rather than chemisorption. In this case, the formation of maghemite catalyzed the attraction of hydrogen molecules and the CNP skeleton was the principal absorbent material for hydrogen storage. However, as the iron content exceeded 14 wt%, the formation of larger and poorly dispersed maghemite grains reduced the available surface areas of CNP for the storage of hydrogen molecules, leading to decreased uptake. Our study shows that hydrogen uptake capacities can be improved by appropriately adjusting the surface polarities of the CNP with well dispersed iron oxides crystals.

Sorption of Bisphenol A in Aqueous Solutions on Irradiated and as-Grown Multiwalled Carbon Nanotubes

2018 ◽  
Vol 69 (5) ◽  
pp. 1233-1239
Author(s):  
Raluca Madalina Senin ◽  
Ion Ion ◽  
Ovidiu Oprea ◽  
Rusandica Stoica ◽  
Rodica Ganea ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Bisphenol A ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Adsorption Process ◽  
Sorption Process ◽  
Multiwalled Carbon ◽  
Before And After ◽  
Kinetic Sorption

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.

scholarly journals Study on Adsorption Properties of Modified Corn Cob Activated Carbon for Mercury Ion

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Physical Adsorption ◽  
Raw Material ◽  
Order Kinetic ◽  
Mercury Ions ◽  
Corn Cob ◽  
Adsorption Time ◽  
X Ray

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.

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