Innovative spinel ferrites for efficient photocatalytic mineralization of carbamazepine in wastewater

Abstract

Cobalt, nickel, and zinc ferrites synthesized by the Pechini method were evaluated as photocatalysts for the degradation of carbamazepine, a widely used antiepileptic drug found in wastewater. X-ray diffraction showed that all samples exhibited a spinel structure with nanometer particle sizes. The cobalt and nickel ferrites showed superior performance due to their lower band gap, with the cobalt ferrites reaching values above 94 % mineralization after two consecutive cycles. The photocatalyst structure remained intact after the cycles performed, with Fe ion leaching of less than 1 % in Co and Ni ferrites and 2 % in Zn ferrites. The drug carbamazepine was mineralized to 98 % in 4 h of photoreaction in a photocatalytic system with UV light, hydrogen peroxide as oxidant and using as catalysts the three studied ferrites. The degradation process followed first-order kinetics with high linear correlations (R2 > 0.95). We could effectively apply the developed method in future wastewater treatment, offering a promising strategy to degrade pharmaceutical compounds. The widespread presence of these compounds poses significant challenges for water treatment systems, and the use of ferrites as photocatalysts represents an innovative approach to address this problem.