Kinetic study of adsorption of tetracycline from an aqueous solution by nanostructured graphene oxide

In this work, an extensive study on the kinetics of tetracycline adsorption using synthesized graphene oxide has been carried out. The first and second-order kinetic model along with the pore volume and surface diffusion model as one of the most sophisticated models for the kinetic studies in adsorption processes have been used to investigate the mass transfer mechanism of tetracycline adsorption. The results show that the intraparticle diffusion through the graphene oxide pores is the main controlling step of the adsorption process. Characterization of the synthesized graphene oxide has been carried out by BET, SEM, FTIR, and XRD techniques. The specific surface area of the graphene oxide was 15.8 m² gr⁻¹ with an average pore diameter of 10 nm. It was found that Langmuir isotherm has the most compatibility with the experimental data and has been used as the adsorption model. The shape of isotherm data indicates that the adsorption process is chemisorption dominated by electrostatic forces.