Thermodynamics studies on the adsorption of phenol from aqueous solution by coffee husk activated carbon

Ta, Huu Son; Le Van, Khu; Luong Thi, Thu Thuy; Nguyen, Dinh Hung

doi:10.21608/ejchem.2021.30318.2648

Thermodynamics studies on the adsorption of phenol from aqueous solution by coffee husk activated carbon

Document Type : Original Article

Authors

¹ Department of Physical Chemistry, Faculty of Chemistry, Hanoi National University of Education, Hanoi, Vietnam

² Vinh Phuc Gifted High School, Vinh Yen City, Vinh Phuc Province, Vietnam

10.21608/ejchem.2021.30318.2648

Abstract

Activated carbons (ACs) obtained from coffee husk by KOH activation at 650 (ACK-650) and 750oC (ACK-750), were used as an adsorbent for the adsorption of phenol from aqueous solution. The ACs was characterized by SEM, EDX, BET, and Boehm titration techniques. The experimental equilibrium data of phenol adsorption was analyzed by eight isotherm models, which are four two-parameter equations (Langmuir, Freundlich, Elovich, and Temkin) and four three-parameter equations (Redlich-Peterson, Sips, Radke-Prausnitz, and Tóth). The results reveal that in general, three-parameter isotherms can provide better prediction than two-parameter isotherms. The best fit for ACK-650 sample is Sips isotherm, while for ACK-750 sample is Redlich–Peterson isotherm. Isosteric heat and thermodynamic parameters ΔGo, ΔHo, and ΔSo of the adsorption were determined, and the results showed that the adsorption of phenol was exothermic and physical in nature. A scale-up of a batch system is designed for 2 to 10 L phenol with an initial concentration of 100 mg L-1.

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