Removal of Antibiotic Sulfamethazine from Aqueous Media Using Watermelon Seeds as a New Low Cost and Ecofriendly Adsorbent

The removal efficiency of sulfamethazine, as a representative antibiotic (SMT), on a new and eco-friendly activated carbon provided from watermelon seeds as adsorbent has been studied in simple systems. Some experimental parameters, namely pH, the amount of adsorbent and contact time are studied. Based on the results, the weak chemical bonds (π-π EDA interactions) are responsible for the adsorption of SMT to watermelon seeds. The present adsorbent played an important role in the sorption of SMT, leading to a higher sorption capacity onto the watermelon seeds (90.78 mg g^-1). The solvent effect is been studied to show that the electron-donor-acceptor (EDA) interaction is the main adsorption mechanism of SMT antibiotic and that adsorption capacity increases with the increase of dipole moment of solvents. A kinetic study showed that the removal efficiency process followed the pseudo-second-order model and the Langmuir isotherm was the best model to fit and describe the phenomenon in the single system.