Photocatalytic degradation of cefixime using CuO-NiO nanocomposite photocatalyst

Organic pollutants have emerged as a threat to the environment due to their excessive usage and subsequent continuous release into the aquatic environment. This concern has necessitated the search for effective tech-nologies to deal with the continuous accumulation of active pharmaceutical ingredients (APIs) as pollutants in the environment. Advanced oxidation processes (AOPs), including photocatalysis, have gained special attention for the removal of APIs and other organic pollutants in water. In order to achieve this goal, CuO-NiO nano-composite photocatalyst with a p-p isotype heterojunction was prepared using the low-cost and facile method of co-precipitation. The composite catalyst was characterized by field emission scanning electron microscopy (FESEM), Thermogravimetric Analysis (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) which indicated the crystalline and mesoporous structure of the nanocomposite. The photocatalytic activity of the nanocomposite catalyst was studied using the degradation of cefixime as the model antibiotic under sunlight. The nanocomposite photocatalyst demonstrated effective catalytic activity against the degradation (90 %) of cefixime following first-order kinetics with a rate constant (k) of 7.4 x 10-3 min-1. The degradation of cefixime was greatly enhanced with catalyst dosage and at lower pH. A radical trapping study indicated hydroxyl radicals and superoxide radicals are responsible for degradation reactions.