scholarly journals Removal of phenol from aqueous solution by Mahua seed activated carbon: Kinetic, isotherm, mass transfer and isosteric heat of adsorption studies

2016 ◽  
Vol 22 (3) ◽  
pp. 263-273
Author(s):  
Yadav Singh ◽  
Mishra Kumar ◽  
Arvind Kumar
Keyword(s):  
Activated Carbon ◽  
Effective Diffusion ◽  
Chemical Properties ◽  
Isosteric Heat ◽  
Sorption Process ◽  
Heat Of Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Homogeneous Surface ◽  
Isosteric Heat Of Adsorption

Mahua (Madhuca longifolia) seed activated carbon (MSAC) has been developed as an effective adsorbent for the removal of phenol from contaminated wastewaters. Prepared MSAC was characterized for various physico-chemical properties, Fourier transform infra- red (FTIR) and scanning electron microscopy (SEM) analysis. Laboratory batch experiments were performed to investigate the effect of MSAC dosage (w), pH, contact time (t), and initial phenol concentrations (Co) on sorption efficiency at optimal conditions. The maximum adsorption capacity of phenol was obtained at pH=6, t=5 h and MSAC dosage=1.2 g/l. The kinetics data of phenol adsorption was very well described by the pseudo-second-order kinetic model. The equilibrium adsorption data were best fitted to the Langmuir isotherm. The average effective diffusion coefficient 6.4?10-13 m2/s was calculated from the experimental data. Thermodynamic studies confirmed the sorption process to be spontaneous and exothermic. The isosteric heat of adsorption of phenol was found to increase with an increase in the surface loading indicating that MSAC have more homogeneous surface.

Adsorption Characteristics of Nitric Oxide and Sulfur Dioxide on Coal Activated Carbon

2011 ◽  
Vol 383-390 ◽  
pp. 3056-3062 ◽  
Author(s):  
Dong Juan Kang ◽  
Xiao Long Tang ◽  
Jin Hui Peng ◽  
Hong Hong Yi ◽  
Ping Ni ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Sulfur Dioxide ◽  
Adsorption Process ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Isotherm Model ◽  
No Adsorption ◽  
Isosteric Heat Of Adsorption

The aim of this paper is to study the adsorption characteristics of nitric oxide (NO) and sulfur dioxide (SO2) on raw coal activated carbon over temperature ranged 298～343K using a static volumetric adsorption apparatus. The adsorption equilibrium data for NO and SO2were fitted to Freundlich, Dubinin-Radushkevich (D-R) and Sips adsorption isotherm model. Isosteric heat of adsorption was determined by the Clausius-Clapeyron equation. It was found that Sips adsorption isotherm model is more suitable for description of NO adsorption process at 298K, 313K and 328K and SO2adsorption process at 313K, 328K and 343K, however, D-R adsorption isotherm model is more suitable for description of the NO adsorption process at 343K and SO2adsorption process at 298K. The isosteric heat of adsorption values of SO2increase slightly as the adsorbed amounts increasing from 0.8 to 1.6mg/g, but the isosteric heat of adsorption values of NO show a converse trend. Meanwhile, NO and SO2adsorbed on coal activated carbon at the four temperatures may be a dominant of physical adsorption.

scholarly journals Adsorption thermodynamics and isosteric heat of adsorption of Thymol onto sodic, pillared and organic bentonite

2019 ◽  
Vol 8 (6) ◽  
pp. 494-504 ◽  
Author(s):  
Mohamed Elmiz ◽  
Kamal Essifi ◽  
Doha Berraaouan ◽  
Samira Salhi ◽  
Abdesselam Tahani
Keyword(s):  
Free Energy ◽  
Activation Parameters ◽  
Freundlich Isotherm ◽  
Isosteric Heat ◽  
Sorption Process ◽  
Heat Of Adsorption ◽  
Batch Adsorption ◽  
Isosteric Heat Of Adsorption ◽  
Adsorbed Quantity ◽  
Cetyl Pyridinium

We studied the temperature effects on thymol adsorption on sodium and modified clays from Nador, Morocco. The clay samples used for these analyses were purified and modified by sodium, Al13 and Cetyl Pyridinium chloride before they were used as an adsorbent for the adsorption of thymol from aqueous solution in batch adsorption procedure. The adsorption experiments were carried out as a function of temperature. The adsorption was found to be strongly dependent on the temperature. The Freundlich isotherm model showed an excellent fit to the equilibrium adsorption data. This equation indicates that the logarithm of KF is a linear function of temperature, and it decreases with temperature. The mean free energy (E) estimated from the Rankine (Calendar) modified model indicated that there is a significant relationship between adsorbed quantity and temperature and the primary mechanism governing the sorption process was a physisorption mechanism. The Arrhenius and Eyring equations were used to obtain the activation parameters such as activation energy (Ea), and enthalpy (ΔH°), entropy (ΔS°) and free energy (ΔG°) of activation for the adsorption system. Thermodynamic studies suggested the spontaneous and endothermic nature of adsorption of thymol green by sodium and purified bentonite. The isosteric heat of adsorption (ΔHX) was also determined from the equilibrium information using the Clausius–Clapeyron equation. ΔHX increased with increase in surface loading, indicating some lateral interactions between the adsorbed molecules.

scholarly journals Insights into Equilibrium and Adsorption Rate of Phenol on Activated Carbon Pellets Derived from Cigarette Butts

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 934
Author(s):  
Nahum A. Medellín-Castillo ◽  
Raúl Ocampo-Pérez ◽  
Angélica Forgionny ◽  
Gladis J. Labrada-Delgado ◽  
Ana I. Zárate-Guzmán ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Effective Diffusion ◽  
Chemical Properties ◽  
Molecular Size ◽  
Maximum Adsorption Capacity ◽  
Leaching Tests ◽  
Solution Ph ◽  
Microporous Material ◽  
Cigarette Butts ◽  
Carbon Pellets

In the present work, the preparation of activated carbon pellets from cigarette butts by thermal treatment was evaluated. The morphological, textural, topological, and surface chemical properties were studied by SEM-EDX, N2 adsorption, Raman, and FTIR spectroscopy. For adsorption assays, activated carbon was tested for the adsorption of phenol as a model molecule at different solution pH, temperature, and type of water. In addition, leaching tests before and after carbonization were conducted to evaluate the lixiviation of ions present in the solid. The results revealed a microporous material, composed of cylindrical fibers (thickness of 13 µm) with a microporous area of 713 m2/g and narrow and uniform slit-shaped pores (0.4–0.8 nm). The surface chemistry analysis evidenced the presence of oxygenated groups (carboxylic, esters, and phenolics). Activated carbon leaching tests indicated that the concentrations of the leached ions did not exceed the maximum permissible limit for drinking water. Phenol adsorption revealed an exothermic process with a maximum adsorption capacity of 272 mg/g at 10 °C. Finally, it was confirmed that phenol diffusion was drastically affected by hindered phenomena due to the similarity in the molecular size of phenol and the average size of micropores, and as a result an effective diffusion coefficient between 6.10 × 10−0 and 5.50 × 10−12 cm2/s and a maximum tortuosity value of 3.3 were obtained.

ADSORPTION CHARACTERISTICS AND HEAT OF ADSORPTION MEASUREMENTS OF R-134a ON GRANULAR ACTIVATED CARBON

2014 ◽  
Vol 22 (03) ◽  
pp. 1450014 ◽  
Author(s):  
M. ATTALLA ◽  
S. SADEK ◽  
W. ABD EL-FADEEL
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Granular Activated Carbon ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Maximum Adsorption Capacity ◽  
Acceptable Error ◽  
Adsorption Characteristics ◽  
Finned Tubes ◽  
R 134A

The objective of this study is to investigate the adsorption characteristics of granular activated carbon GAC/R-134a pair in the temperature range of 20–60°C and pressure up to 10 bars. The Dubinin–Astakhov adsorption equilibrium model is fit to experimental data with acceptable error limit. The pressure–temperature–concentration (P–T–X) diagram of the pair is also presented. The isosteric heat of adsorption of R-134a on AC has been calculated using the Clausius–Clapeyron equation as a function of adsorption capacity. The maximum adsorption capacity was found to be 1.92 kgR134a/kgcarbon at 20°C after 1200 s. The experimental results also shows that the increase of heat transfer area improves the adsorption capacity per kg of adsorber, which lead to the design of a finned tubes heat exchanger adsorption unit.

Equilibrium Analysis of Hydrogen Adsorption on Activated Carbon

2012 ◽  
Vol 472-475 ◽  
pp. 1652-1658
Author(s):  
Qing Rong Zheng ◽  
Shuai Gao ◽  
Chen Jie
Keyword(s):  
Activated Carbon ◽  
Hydrogen Storage ◽  
Surface Coverage ◽  
Hydrogen Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Equilibrium Analysis ◽  
Isosteric Heat Of Adsorption ◽  
Adsorption Data ◽  
Adsorption Isosteres

For developing carbon based adsorbents for hydrogen storage, Staram PCTPro E&E was employed and activated carbon SAC-02 having specific surface area about 2074m2/g was selected to measure isotherms of hydrogen adsorption respectively from temperature range 77.15K-110.15K and 253.15K-293.15K. Isosteres of hydrogen adsorption on the activated carbon was then plotted to determine the isosteric heat of hydrogen adsorption, and temperature dependent of Henry law constants were further applied to set the limit isosteric heat of adsorption at zero surface coverage. Results show that the isosteric heat of adsorption is about 3.6-5.4kJ/mol with a mean value 4.38kJ/mol at zero surface coverage. Results also reveal that adsorption isosteres of adsorption data at different temperature regions bring about a different isosteric heat of adsorption due to the variation in contributions from thermal motion of adsorbate molecules. Conclusions are drawn that adsorption isosteres on the adsorption data in correspondence with the lowest and highest temperatures of the hydrogen storage system should be carried out to determine the isosteric heat of adsorption for effectively managing the thermal effect.

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