Removal of oxytetracycline hydrochloride from aqueous solutions using natural zeolite

Purpose: Antibiotics have been widely used in human and veterinary medicines and the presence of antibiotics in the environment causes environmental pollution. For this reason, in this study, we investigated the adsorption of OTC-HCL from aqueous solutions with natural zeolite in a batch reactor.Theory and Methods: Adsorption is commonly known as the mass transfer of organic matter from a liquid phase onto the surface of a solid and it is extensively used in water treatment due to its cheap and efficient treatment. In the present study the effects of some parameters such as pH, initial concentration, adsorbent dosage, contact time, stirring speed and temperature on adsorption were examined. The adsorption process at equilibrium was investigated with Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin models. Kinetic data were examined with pseudo-first order (PFO), pseudo-second order (PSO), intraparticle diffusion and Elovich kinetics. Zeolite characterization was analyzed by N2 adsorption-desorption, XRD, FTIR, SEM-EDX instruments.Results: Adsorption of OTC-HCL on natural zeolite fitted well to the Freundlich and pseudo-second-order models. The maximum adsorption capacity of natural zeolite was determined as 60.97 mg/g at 323 K. Thermodynamic studies indicated that the adsorption of OTC-HCL on natural zeolite was spontaneous and endothermic. Characterization results showed that the adsorption of OTC-HCL on natural zeolite was successfully achieved.Conclusion: Natural zeolites may be an efficient adsorbent for the removal of antibiotics and the present study may constitute a sample for a new adsorbent.