Investigation of adsorption properties of oxytetracycline hydrochloride on magnetic zeolite/Fe3O4 particles

Iron oxides and ferrite-supported zeolites have been successfully used in the cheap and environmentally friendly removal of organic pollutants such as antibiotics. In this study, the adsorption of Oxytetracycline hydrochloride (OTC-HCL) on zeolite/Fe3O4 particles synthesized from natural Manisa-Gördes clinoptilolite by co-precipitation method was investigated in the batch system at 298–323 K. Various parameters such as pH, initial antibiotic concentration, adsorbent dosage, contact time, stirring speed and temperature were examined and optimum parameters were determined according to experimental data. Adsorption isotherms were investigated with Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin models. Kinetic constants were determined according to pseudo first order, pseudo second order, intraparticle diffusion and Elovich models. OTC-HCL adsorption on zeolite/Fe3O4 best fitted to the Langmuir isotherm and pseudo second order kinetic models. The maximum adsorption capacity of zeolite/Fe3O4 was determined as 83.33 mg/g at 323 K. Adsorption of OTC-HCL on zeolite/Fe3O4 occurred spontaneously and endothermic. Physicochemical characterization of zeolite/Fe3O4 was performed before and after adsorption, by N2 adsorption-desorption, XRD, FTIR, SEM-EDX, XPS, TEM analyses. Magnetic properties of zeolite/Fe3O4 were determined by VSM analysis. The BET specific surface area of zeolite/Fe3O4 decreased after adsorption of OTC-HCL. VSM and SEM-EDX results showed that zeolite/Fe3O4 had superparamagnetic property and OTC-HCL adsorbed on zeolite/Fe3O4 successfully.