ORIGINAL RESEARCH
A Thermodynamic and Kinetic Evaluation
of the Adsorption of Pb(II) Ions Using Peanut
(Arachis Hypogaea) Shell-Based Biochar
from Aqueous Media
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Department of Chemical Engineering, Firat University, Elazig, Turkey
Submission date: 2018-11-30
Final revision date: 2019-01-16
Acceptance date: 2019-01-19
Online publication date: 2019-08-09
Publication date: 2019-10-23
Corresponding author
Şeyda Taşar
Chemical Engineering, adsorption, heavy metal pollution, environmental technology, smart polymer, hydogel, sorption, pyrolysis and combustion, Firat University, Faculty of Engineering, Departme, 23279, Elazig, Turkey
Pol. J. Environ. Stud. 2020;29(1):293-305
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ABSTRACT
In this study, biochar from peanut shells was used to remove Pb(II) ions from aqueous media using a
batch method. Adsorption studies were conducted to optimize the adsorption parameters, such as contact
time, the initial pH of aqueous media, temperature, initial concentration of lead ions, and the dosage
of biochar. The optimum adsorption conditions were found to be contact time: 180 min, initial pH of
aqueous media: 5.5 0.02, temperature: 293 K, initial concentration of lead ions: 100 ppm, and the dosage
of biochar: 2 g/L. The adsorption yield of Pb(II) ions on the biochar was found to be 89% under these
conditions. The experimental results were evaluated by applying the Langmuir, Freundlich, Temkin,
and Dubinin-Radushkevich (D-R) isotherm models. We found that the Langmuir isotherm describe
the adsorption data very well. The theoretical maximum adsorption capacity (qc) was determined as
56.5 mg/g using the Langmuir isotherm. In the concept of the research, kinetic investigations also were
conducted. Pseudo first-order, pseudo second-order, intraparticle diffusion, and Endovich kinetic models
were used to calculate the kinetic parameters and determine the ideal mechanism of the adsorption
process. It was found that the pseudo second-order model could be used to explain the experimental data.
The adsorption was a controlled chemisorption mechanism. The thermodynamic parameters (ΔHº, ΔSº,
and ΔGº) were calculated using basic thermodynamic equations, and they indicated that the adsorption
process was spontaneous at all temperatures and that the process was exothermic. Consequently, it was
concluded that the peanut shell-based biochar can be used as a suitable and economical adsorbent for the
removal of Pb(II) ions from aqueous media.