scholarly journals Comparison of the Thermodynamic Parameters Estimation for the Adsorption Process of the Metals from Liquid Phase on Activated Carbons

Author(s):  
Svetlana Lyubchik ◽  
Andrey Lyubchik ◽  
Olena Lygina ◽  
Sergiy Lyubchik ◽  
Isabel Fonsec
2014 ◽  
Vol 936 ◽  
pp. 829-833
Author(s):  
Hai Song ◽  
Xing Hai Yu ◽  
Xiao Qin Zhang ◽  
Gui Fang Yan ◽  
Yuan Zhi Zhen

The purpose of this work is to prepare a low-cost biosorbent,Porous Magnetic/Chitosan Resin(MCR), and determine the ability of this biosorbent to removing Ni (II) ion from aqueous medium. Both kinetics and thermodynamic parameters of the adsorption process were also estimated. The thermodynamic parameters indicated an exothermic spontaneous process and the kinetics followed the second-order adsorption process.


2016 ◽  
Vol 73 (8) ◽  
pp. 2007-2016 ◽  
Author(s):  
N. Contreras Olivares ◽  
M. C. Díaz-Nava ◽  
M. Solache-Ríos

The sorption processes of red 5 (R5) and yellow 5 (Y5) dyes by iron modified and sodium bentonite in aqueous solutions was evaluated. The modified clay was prepared, conditioned and characterized. The sodium clay did not remove any of either dye. The sorption kinetics and isotherms of R5 and Y5 dyes by iron modified clay were determined. The maximum removal percentages achieved were 97% and 98% for R5 and Y5, respectively, and a contact time of 72 h; the experimental data were best adjusted to Ho model. The isotherms of both dyes were best adjusted to the Langmuir model and the maximum adsorption capacities of the modified clay were 11.26 mg/g and 5.28 mg/g for R5 and Y5, respectively. These results indicate that adsorption processes have a high probability to be described as chemisorption on a homogeneous material. Temperature range between 283 and 213 K does not affect the adsorption of Y5 by the iron modified clay, but the adsorption process of R5 was affected, and the thermodynamic parameters could be calculated, which indicate a chemisorption mechanism.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Geni Juma ◽  
Revocatus Machunda ◽  
Tatiana Pogrebnaya

In this study, sweet potato leaf activated carbon (SpLAC) was prepared by the chemical activation method using KOH and applied as an adsorbent for H2S removal from biogas. The study focused on the understanding of the effect of carbonization temperature (Tc), varying KOH : C activation ratio, flow rate (FR) of biogas, and mass of SpLAC on sample adsorption capacity. The BET analysis was performed for both fresh and spent activated carbons as well as for carbonized samples, which were not activated; also, the activated carbon was characterized by XRF and CHNS techniques. The results showed that removal efficiency (RE) of the SpLAC increased with increase carbonization temperature from 600 to 800°C and the mass of sorbent from 0.4 g to 1.0 g. The optimal test conditions were determined: 1.0 g of sorbent with a KOH : C ratio of 1 : 1, Tc=800°C, and FR=0.02 m3/h which resulted in a sorption capacity of about 3.7 g S/100 g of the SpLAC. Our findings corroborated that H2S removal was contributed not only by the adsorption process with the pore available but also by the presence of iron in the sample that reacted with H2S. Therefore, upon successful H2S sorption, SpLAC is suggested as a viable adsorbent for H2S removal from biogas.


Clay Minerals ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 85-95 ◽  
Author(s):  
İ. Sargin ◽  
N. Ünlü

AbstractIn this study, adsorption and adsorption kinetics of methyl violet dye from aqueous solutions onto kaolinite were investigated. The effects of adsorbent dosage, pH, ionic strength, contact time, temperature and initial dye concentration were studied. Kinetic and thermodynamic parameters were determined using experimental data. Adsorption capacity decreased with increasing ionic strength. Changes in the initial pH of the dye solution in a range close to the dye's natural pH (i.e. ∼ pH 5.0) values affected adsorption capacity slightly, indicating that adsorption studies could be carried out at the dye's natural pH. The adsorption process followed the Freundlich-type adsorption isotherms and pseudo-second order type adsorption kinetics. However, an intraparticle diffusion process was found to have effects in adsorption processes. Thermodynamic parameters were calculated from the experimental data and enthalpy of the adsorption, ΔH0, was found to be –6.82 kJ mol–1, indicating physisorption nature of the adsorption. Other thermodynamic parameters, ΔS0 and DG0, were also calculated. Negative values of ΔG0 indicated that the adsorption process for methyl violet on kaolinite is spontaneous.


2011 ◽  
Vol 699 ◽  
pp. 245-264 ◽  
Author(s):  
A. Xavier ◽  
J. Gandhi Rajan ◽  
D. Usha ◽  
R Sathya

Methylene blue is a heterocyclic aromatic chemical compound with the molecular formula C16H18N3SCl. It has used in the biology and chemistry field. At room temperature, it appears as a solid, odourless dark green powder that yields blue solution when dissolved in water. As a part of removal of methylene blue dye from textile and leather industrial wastes, using activated carbon as adsorbents namely, commercial activated carbon (CAC), rose apple carbon (RAC), coconut shell carbon (CSC) and saw dust carbon (SDC). The percentage of Methylene blue adsorbed increases with decrease in initial concentration and particle size of adsorbent and increased with increase in contact time, temperature and dose of adsorbents. The pH is highly sensitive for dye adsorption process. The adsorption process followed first order kinetics and the adsorption data the modeled with Freundlich and Langmuir isotherms. The first kinetic equations like Natarajan Khalaf, Lagergren, Bhattacharya and Venkobhachar and intra particle diffusion were found to be applicable. A comparative account of the adsorption capacity of various carbons has been made. These activated carbons are alternative to commercial AC for the removal dyes in General and MB is particular. These results are reported highly efficient and effective and low cost adsorbent for the MB. The thermodynamics parameters are also studied and it obeys spontaneous process. The results are confirmed by before and after adsorption process with the help of the following instrumental techniques viz., FT-IR, UV-Visible Spectrophotometer and SEM photos.


2003 ◽  
Vol 21 (5) ◽  
pp. 463-473
Author(s):  
J. Barkauskas ◽  
A. Vinslovaite

The adsorption of polyvinyl alcohol (PVA) on activated carbons was studied in aqueous solutions. Each batch of activated carbon produced was obtained via a definite number of technological operations using wood as the raw material. The adsorption process was studied using a gel chromatography technique with potentiometric titrations being employed for evaluating the chemical composition of the activated carbons produced. The data obtained from the various activated carbon samples were compared to ascertain the adsorption mechanism. It was concluded that water molecules had a limited influence on the competitive process of polymer adsorption. A rather pronounced negative correlation between the number of phenol functional groups and PVA adsorption capacity was observed, indicating that these groups hindered the adsorption process. Assumptions concerning the role of phenol functional groups were made, taking into account not only the surface heterogeneity but also changes in the electron density of the graphene layers in the carbon substrate.


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