Thermodynamic Analysis for Adsorption of Amoxicillin onto Magnetic Carbon Nanotubes
Davoud Balarak
Department of Environmental Health, Health Promotion Research Center, School of Public Health, Zahedan University of Medical Sciences, Zahedan, Iran.
Ferdos Kord Mostafapour
Department of Environmental Health, Health Promotion Research Center, School of Public Health, Zahedan University of Medical Sciences, Zahedan, Iran.
Ali Joghtaei *
Student Research Committee, Qom University of Medical Sciences, Qom, Iran.
*Author to whom correspondence should be addressed.
Abstract
The effect of temperature on the equilibrium adsorption of Amoxicillin (AMO) from aqueous solution using modified magnetic multi-walled carbon nanotubes (MMWCNTS) was investigated. The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir, Freundlich and Tempkin. The results revealed that Langmuir isotherm fit the experimental results well. Kinetic analyses were conducted using pseudo-first and second-order models and the intraparticle diffusion model. The regression results showed that the adsorption kinetics were more accurately represented by pseudo-second-order model. Standard free energy changes (△G0), standard enthalpy change (△H0), and standard entropy change (△S0) were calculated at different temperatures. The △G0 values were negative and △H0 values and △S0 values of MMWCNTS were positive; and suggested that the AMO adsorption on MMWCNTS was a spontaneous and endothermic process.
Keywords: Adsorption, MMWCNTS, isotherm, amoxicillin, thermodynamics