Adsorption of hexavalent chromium from aqueous solution by activated carbon prepared from longan seed: Kinetics, equilibrium and thermodynamics

Activated carbon was prepared from longan seed by chemical activation with sodium hydroxide (NaOH). The longan seed activated carbon (LSAC) was characterized for surface area and pore volume and used as an adsorbent for Cr(VI) removal from aqueous solutions in batch adsorption experiments. The effec...

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Published inJournal of industrial and engineering chemistry (Seoul, Korea) Vol. 21; pp. 414 - 422
Main Authors Yang, Jinbei, Yu, Meiqiong, Chen, Wentao
Format Journal Article
LanguageEnglish
Published Elsevier B.V 25.01.2015
한국공업화학회
Subjects
Activated carbon
Adsorbents
Adsorption
Aqueous solutions
Chromium removal
Isotherms
Kinetic parameters
Longan
Longan seed activated carbon
Mathematical models
Seeds
Surface chemistry
Wastewater treatment
화학공학
Chromium removal
Adsorption
Kinetic parameters
Wastewater treatment
Longan seed activated carbon
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Summary:Activated carbon was prepared from longan seed by chemical activation with sodium hydroxide (NaOH). The longan seed activated carbon (LSAC) was characterized for surface area and pore volume and used as an adsorbent for Cr(VI) removal from aqueous solutions in batch adsorption experiments. The effect of shaking speed, pH, LSAC dosage and temperature were studied. The results show that LSAC has a high surface area (1511.8m2/g) and porous structure, which is favorable for the adsorption. The effect of external diffusion is eliminated at 170rpm, the best pH value is 3.0 and the removal percentage of Cr(VI) increases with the increase of the LSAC dosage. The adsorption process can be well described by the pseudo second-order kinetic model and the activation energy is 84.4kJ/mol. The adsorption isotherms data of Cr(VI) on LSAC obtained at 298.2, 308.2, 313.2 and 318.2K were analyzed by Langmuir and Freundlich isotherm models and results show that it is better represented by the Langmuir isotherm model. The thermodynamics parameters, ΔH=2.73kJ/mol, ΔS=28.14J/molK and ΔG<0, show that the adsorption of Cr(VI) on LSAC is spontaneous and endothermic. The results show that LSAC is an efficient adsorbent for the removal of Cr(VI) from aqueous solutions.
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G704-000711.2015.21.1.157
ISSN:1226-086X
1876-794X
DOI:10.1016/j.jiec.2014.02.054