Degradation of Amoxicillin Trihydrate (AMT) with suspended/immobilized TiO2 catalyst and Parabolic Trough Collector

Abstract

Heterogeneous photocatalytic degradation of AMT using TiO2 in suspension form as well as immobilized form was investigated in the present study. The degradation rate was observed to follow first-order kinetics. TiO2 loading 0.5 g L-1, pH 5.8, C0 100 mg L-1 were the optimized conditions for obtaining the better degradation rates. Cement beads and alginate balls were used for the immobilization of TiO2 for the degradation of AMT. 87%, 69% and 52% degradation was observed under shallow pond slurry reactor, coated cemented beads, immobilized sodium alginate ball using solar irradiation. Reduction in COD and TOC values along with the generation of ammonium further indicated the mineralization of the AMT. The effect of initial concentration, catalyst recycling as well as area/volume was also studied for the practical applications. Experiments conducted on Parabolic Trough Collector (PTC) with TiO2 immobilized cement beads at the flow rate of 0.1Lmin-1 in the presence of oxidant (0.12 gL-1) yielded 92% degradation within 4 h of irradiation as confirmed by LC-MS technique. Durability studies were conducted and the structure of TiO2 was found to be intact after fourth recycle. XRD and solid spectra analysis of TiO2 confirmed that no deformities occurred in the structure of the catalyst after use. Thus, use of renewable energy along with a durable catalyst can be a promising technique for degrading bio recalcitrant compounds from commercial point of view.