Removal of antibiotic from aqueous solution using synthesized TiO2 nanoparticles: characteristics and mechanisms

We investigated the removal of cefixime antibiotic (CEF) from aqueous solution using TiO2 nanoparticles (TiO2-NPs) in the present study. The TiO2-NPs, which were successfully synthesized using sol-gel method, were characterized by X-ray diffraction, scanning electron microscopy and Fourier transformation infrared spectroscopy (FT-IR) techniques. The removal of CEF using synthesized TiO2-NPs as a photocatalyst with ultraviolet (UV) light was evaluated by the UV spectroscopic method. The optimum parameters for removal of CEF using TiO2-NPs such as contact time, pH of solution, initial concentration of CEF and dosage of TiO2-NPs were systematically studied and found to be 90 min, 6.0, 80 ppm and 0.1 mg/mL, respectively. The degradation efficiency of about 90% was achieved under the optimum conditions. Experimental kinetic results, which were fitted by the pseudo-second-order model, were much better than with pseudo-first order. The changes in surface charge of TiO2-NPs and surface functional groups were evaluated by zeta potential measurements and FT-IR, respectively. Based on UV spectroscopy, FT-IR spectroscopy and zeta potential measurements, we demonstrate that the removal mechanism of CEF is photocatalytic degradation by TiO2-NPs catalysis than adsorption of CEF onto TiO2.