Studies on the adsorption of amoxicillin on multi-wall carbon nanotubes

This study examined the feasibility of removing amoxicillin (AMO) from aqueous solutions using multi-wall carbon nanotubes. The equilibrium adsorption data were analyzed using four widely applied isotherms: Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The results showed that the Langmuir isotherm model fits well the obtained experimental data. The adsorption process followed the pseudo-second-order model. The activation energy was found to be 19 kJ/mol. The Standard free energy changes, ΔG⁰, values were negative; the standard enthalpy change (ΔH⁰), and standard entropy change (ΔS⁰) values of the process were 4 kJ/mol and 36 J/mol.K. Results suggested that the AMO adsorption on carbon nanotubes was a spontaneous process.