EFFECTIVE ADSORPTION OF TETRACYCLINE WITH Co3O4/Fe3O4 BIMETALLIC NANOPARTICLES

Abstract

In the present study cobalt oxide/iron oxide bimetallic nanoparticles (Co3O4/Fe3O4 NPs) were synthesized by chemical coprecipitation method. The synthesized Co3O4/Fe3O4 NPs were characterized by SEM and XRD analysis. The synthesized nanoparticles were used as an adsorbent for the removal of a kind of antibiotic as Tetracycline (TC) from aqueous solutions. According to characterization results, small plate-like structures and agglomerated irregular spherical nanosized particles (101.85 ± 15.04 nm) were formed. The XRD data confirmed the structure of synthesized adsorbent was Co3O4/Fe3O4. The optimum tetracycline adsorption conditions were determined as the initial pH of solution 9.0, temperature 55°C, and adsorbent concentration 3.0 g/L. A linear increase was observed in equilibrium uptakes of TC with the increasing the initial antibiotic concentrations. The experimental equilibrium data was modelled with Langmuir and Freundlich isotherm models. The experimental equilibrium data was the best agreement to the Langmuir isotherm model. The maximum monolayer coverage capacity of Co3O4/Fe3O4 NPs for TC adsorption was found to be 149.26 mg/g at 55°C optimum temperature. The experimental kinetic adsorption data were defined as the best agreement with the pseudo-second-order kinetic model. Weber Morris mass transfer modelling results showed that both the film (boundary layer) and intra-particle diffusion were effective in the adsorption process. The thermodynamic studies suggested that the adsorption process was endothermic, spontaneous and the positive ΔS value indicated increased disorder at the solid-solution interface during the adsorption. Moreover, the synthesized adsorbent showed high adsorption efficiencies at the end of seven sequence usages.