Cobalt oxide loaded graphitic carbon nitride as adsorptive photocatalyst for tetracycline removal from aqueous...

The treatment of antibiotic-containing wastewater is of great importance due to the potential threats of antibiotics to human and the ecosystem. We reported the preparation of cobalt oxide loaded graphitic carbon nitride (CoO/g-C₃N₄) by an impregnation-calcination method for tetracycline (TC) removal from aqueous solution. The developed CoO/g-C₃N₄ exhibited high adsorption capacity and fast adsorption kinetic for TC due to the complexation of TC with surface loaded CoO. In particular, 7%CoO/gC₃N₄3 sample presented a maximum TC adsorption capacity of 391.4 mg g^-1. It was found that Langmuir and pseudo-second order kinetic models fitted TC adsorption process well. Further photocatalytic studies showed that CoO loaded g-C₃N₄ was active for TC photodegradation, although the photocatalytic reaction rate constant was lower than that of native g-C₃N₄. CoO nanoparticles loading on g-C₃N₄ played the major role of adsorption sites rather than cocatalyst for photocatalysis. We believe that the developed CoO/g-C₃N₄ could be a potential adsorptive photocatalyst for antibiotic pollutants removal from wastewater.