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 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.

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.

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

scholarly journals AC Susceptibility Studies under DC Fields in Superspinglass Nanomaghemite-Multiwall Carbon Nanotube Hybrid

2021 ◽  
Vol 7 (4) ◽  
pp. 52
Author(s):  
Juan A. Ramos-Guivar ◽  
F. Jochen Litterst ◽  
Edson C. Passamani
Keyword(s):  
Carbon Nanotubes ◽  
Ac Susceptibility ◽  
Multiwall Carbon Nanotubes ◽  
Blocking Temperature ◽  
Multiwall Carbon Nanotube ◽  
Fe2o3 Nanoparticles ◽  
Different Temperatures ◽  
Fe2o3 Nanoparticle ◽  
Average Size ◽  
Multiwall Carbon

Magnetic properties of maghemite (γ-Fe2O3) nanoparticles grown on activated multiwall carbon nanotubes have been studied by alternating current (AC) magnetic susceptibility experiments performed under different temperatures, frequencies, and applied magnetic fields. Transmission electron images have suggested that the γ-Fe2O3 nanoparticles are not isolated and have an average size of 9 nm, but with a relatively broad size distribution. The activation energies of these 9 nm γ-Fe2O3 nanoparticles, determined from the generalized Vogel–Fulcher relation, are reduced upon increasing the direct current (DC) field magnitude. The large activation energy values have indicated the formation of a superspinglass state in the γ-Fe2O3 nanoparticle ensemble, which were not observed for pure γ-Fe2O3 nanoparticles, concluding that the multiwall carbon nanotubes favored the appearance of highly concentrated magnetic regions and hence the formation of superspinglass state. Magnetic relaxation studies, using Argand diagrams recorded for DC probe fields (<20 kOe) below the magnetic blocking temperature at 100 and 10 K, have revealed the presence of more than one relaxation process. The behavior of the ensemble of γ-Fe2O3 nanoparticles can be related to the superspinglass state and is also supported by Almeida–Thouless plots.

Response surface methodology for cadmium biosorption on Pseudomonas aeruginosa

2016 ◽  
Vol 73 (11) ◽  
pp. 2608-2615 ◽  
Author(s):  
Salman Ahmady-Asbchin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Quadratic Model ◽  
Physicochemical Factors ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Contact Exposure ◽  
Adsorption Equilibrium Data ◽  
Biosorption Equilibrium

In this research the effects of various physicochemical factors on Cd2+ biosorption such as initial metal concentration, pH and contact exposure time were studied. This study has shown a Cd2+ biosorption, equilibrium time of about 5 min for Pseudomonas aeruginosa and the adsorption equilibrium data were well described by Langmuir equation. The maximum capacity for biosorption has been extrapolated to 0.56 mmol.g−1 for P. aeruginosa. The thermodynamic properties ΔG0, ΔH0, and ΔS0 of Cd2+ for biosorption were analyzed by the equilibrium constant value obtained from experimented data at different temperatures. The results show that biosorption of Cd2+ by P. aeruginosa are endothermic and spontaneous with ΔH value of 36.35 J.mol−1. By response surface methodology, the quadratic model has adequately described the experimental data based on the adjusted determination coefficient (R2 = 0.98). The optimum conditions for maximum uptake onto the biosorbent were established at 0.5 g.l−1 biosorbent concentration, pH 6 for the aqueous solution, and a temperature of 30 °C.

Supercapacitor performance of binder-free buckypapers from multiwall carbon nanotubes synthesized at different temperatures

2016 ◽  
Vol 253 (12) ◽  
pp. 2406-2412 ◽  
Author(s):  
K. M. Popov ◽  
V. E. Arkhipov ◽  
A. G. Kurenya ◽  
E. O. Fedorovskaya ◽  
K. A. Kovalenko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwall Carbon Nanotubes ◽  
Different Temperatures ◽  
Supercapacitor Performance ◽  
Binder Free ◽  
Multiwall Carbon

scholarly journals Kinetic Modelling of Naphthalenesulphonic Acid Adsorption from Aqueous Solution onto Untreated and Ozonated Activated Carbons

2009 ◽  
Vol 27 (4) ◽  
pp. 395-411 ◽  
Author(s):  
R. Leyva-Ramos ◽  
J. Rivera-Utrilla ◽  
N.A. Medellín-Castillo ◽  
M. Sánchez-Polo
Keyword(s):  
Adsorption Equilibrium ◽  
Activated Carbons ◽  
Kinetic Modelling ◽  
Effective Diffusion ◽  
Intraparticle Diffusion ◽  
Adsorption Rate ◽  
Decay Data ◽  
Equilibrium Data ◽  
Diffusional Model ◽  
Adsorption Equilibrium Data

The adsorption rate of 1-naphthalenesulphonic (NS), 1,5-naphthalenedisulphonic (NDS) and 1,3,6-naphthalenetrisulphonic (NTS) acids onto activated carbon (AC) was studied in this work. In addition, the effect of oxidizing the AC with ozone on the rate of adsorption was investigated. The adsorption equilibrium data as well as the concentration decay data for the naphthalenesulphonic acids (NSAs) were obtained in a batch adsorber. The Freundlich, Langmuir and Prausnitz–Radke isotherms were fitted to the experimental adsorption equilibrium data when it was found that the Prausnitz–Radke isotherm gave the best fit. The experimental concentration decay data were interpreted via a diffusional model which considered the adsorption rate at a surface site, external mass transport and intraparticle diffusion. The results revealed that intraparticle diffusion was the controlling mechanism in the diffusional model and that this model predicted the experimental data satisfactorily. The effective diffusion coefficients of the NSAs could be estimated using the tortuosity factor equation together with tortuosity factors for the ACs ranging from 3.7 to 5.5.

Role of adsorption in water environment processes

1997 ◽  
Vol 35 (7) ◽  
pp. 1-11 ◽  
Author(s):  
Motoyuki Suzuki
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Water Environment ◽  
Activated Carbon Fiber ◽  
Biological Activated Carbon ◽  
Liquid Phase Adsorption ◽  
Equilibrium Data ◽  
Isotherm Equations ◽  
Adsorption Rates ◽  
Adsorption Equilibrium Data

Aqueous phase adsorption isotherms and adsorption rates are reviewed. Among numbers of isotherm equations, a combination of adsorption potential and solvophobic concept was applicable to interpreting adsorption equilibrium data obtained for agrochemicals on activated carbon fiber. Intraparticle diffusion becomes the rate-limiting step in liquid phase adsorption on granular activated carbons. Correlation of diffusion coefficients based on surface diffusion mechanisms is introduced. As topics related to adsorption, sediment water partition, biological activated carbon, removal of volatile organics and nutrient removal are briefly reviewed.

Boehmite Nanofibers as a Dispersant for Nanotubes in an Aqueous Sol

2018 ◽  
Author(s):  
Gen Hayase
Keyword(s):  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Aqueous Solutions ◽  
High Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
Multiwall Carbon ◽  
Nanotube Films

By exploiting the dispersibility and rigidity of boehmite nanofibers (BNFs) with a high aspect ratio of 4 nm in diameter and several micrometers in length, multiwall-carbon nanotubes (MWCNTs) were successfully dispersed in aqueous solutions. In these sols, the MWCNTs were dispersed at a ratio of about 5–8% relative to BNFs. Self-standing BNF–nanotube films were also obtained by filtering these dispersions and showing their functionality. These films can be expected to be applied to sensing materials.

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