Adsorption Thermodynamics, Kinetics and Mechanism for the Adsorption of Erythromycin onto Multi-Walled Carbon Nanotubes

The ability of multi-walled carbon nanotubes (MWCNT) to adsorb the Erythromycin antibiotic from aqueous solution was studied through the batch experiments. The adsorption of Erythromycin onto MWCNT was found to be dependent on adsorbent dose, initial concentration and contact time. The experiments were carried out at natural solution pH. Based on the observed results, the highest removal efficiency was achieved to be 99.4% under optimum conditions. The adsorption kinetic results showed that the pseudo-second order model was more suitable to explain the adsorption of Erythromycin onto MWCNT. The adsorption mechanism results showed that the adsorption process was controlled by both the internal and external diffusion of Erythromycin molecules. The values of free energy change (Delta G(0)) and enthalpy change (Delta H-0) revealed that the adsorption process has the spontaneous, feasible, and endothermic nature.