Study of photocatalytic activity of cobalt ferrite in the diclofenac sodium degradation

Abstract

Pharmaceuticals compounds, like sodium diclofenac, are emerging pollutants that have been detected in wastewater and surface waters throughout the world. Their presence was demonstrated in South American rivers, in particular in the Suquía River basin, Córdoba, Argentina. There are several recent studies on applications of ferrite as photocatalyst used in the degradation of pollutants were reported. In this work cobalt ferrites synthetized by Pechini method were calcined at 600°C and 800°C. By XRD patterns were determine that both samples had spinel structure. By XPS and Mössbauer spectroscopy it was found that the material calcined at 600°C is an inverse spinel with a 74% of inversion. The ferrite calcined at 800°C presented a higher percentage (83%) of inversion in its structure. Both materials showed good magnetic properties, which is promising to facilitate their recovery from wastewater effluents. A solution of 40 ppm of sodium diclofenac were 100% degraded in 15 minutes of the photoreaction using Uv-germicide lamp, H2O2 as an oxidant and a cobalt ferrite as catalyst. The cobalt ferrite calcined at 800°C reached 86% of mineralization in 4 hours of photoreaction.