Adsorption potential of spherical ZnO particles for sufficient antibiotic removal: isotherm, kinetic and thermodynamics

Due to the improvements of pharmaceutical industry, tetracycline (TC) is commonly detected in natural water environments, resulting in significant adverse impacts on living species. In this study, the TC adsorption over commercial spherical zinc oxide (ZnO) samples was systematically examined by considering adsorption isotherm models, kinetic model and thermodynamic behavior. The Langmuir kinetic model displayed the highest correlation coefficient (R2 = 0.97) with a maximum adsorption capacity of 86.35 mg/g. According to the results of the kinetic studies, the adsorption could be driven by both the bulk transfer of adsorbate molecules towards the adsorbent surface within the solution and chemisorption on the surface and inside the pores. In addition, the TC adsorption on the ZnO particles promoted by increasing temperature. The commercial spherical zinc oxide can be considered as a sustainable strategy to eliminate the emerging toxic contaminant of tetracycline.