Modeling, Optimization and Kinetic Study for Photocatalytic Treatment of Ornidazole Using Slurry and Fixed-Bed Approach

Abstract

Ornidazole is a well-known antibiotic which has been widely used for both human and veterinary treatments. The present study investigated the degradation of ornidazole using $$\hbox {TiO}_{2}$$ as a photocatalyst with UV light irradiation. Artificial neural network (ANN) was applied for the modeling of the photocatalytic degradation of ornidazole. In slurry mode, the input parameters were pH, ornidazole concentration, $$\hbox {TiO}_{2}$$ dose, treatment time and % degradation as output. Parametric optimization was performed by Box–Behnken design (BBD). At optimum conditions the % degradation was found to be 84.02, 82.63 and 77.7% as predicted by BBD, simulated by ANN and by experimental run respectively. The results showed that the predictions agreed with the experimental results. The degradation of ornidazole follows the second-order reaction kinetics. For fixed-bed studies, $$\hbox {TiO}_{2}$$ immobilized spherical cement beads were used to carry out the degradation of ornidazole at laboratory scale as well as at pilot scale with volume handling of 5 L. The catalyst immobilized beads were successfully recycled for at-least 40 runs without any significant reduction in the degradation efficiency of ornidazole. The activity as well as stability of immobilized catalyst over the surface of beads was confirmed through SEM/EDS, XRD and DRS analysis. Bioassay test was conducted for the safe disposal of treated wastewater and was found to be non-toxic.