Innovative approach of in-situ fixed mode dual effect (photo-Fenton and photocatalysis) for ofloxacin degradation

摘要

Novel composite materials composed of clay, foundry sand (FS), and fly-ash (FA) have been employed to immobilize TiO2 for incorporating in-situ dual effect for the degradation of antibiotic ofloxacin. The in-situ generation of iron from the composite beads with surface active TiO2 induced the dual effect of photo-Fenton and photocatalysis. FA/FS/TiO2 beads illustrated the best results (92% removal) at optimized conditions in the batch reactor experiments. The increment in the rate constant along with a decrease in treatment time for the dual effect has proven the credentials of the in-situ dual effect. Synergy in first-order rate constant using dual process was 51% over the single processes of photo-Fenton and photocatalysis. After 35 recycles the viability of the composed beads was observed through SEM/EDS, UV-DRS and FT-IR analysis, which further justified its use industrially. Estimation of nitrate, nitrite, and ammonia as its by-products was performed for the confirmation of mineralization. Generation of the intermediate products was also identified through GC-MS analysis, and a degradation pathway was proposed. Toxicity test confirming the nontoxic nature of the treated solution was performed on E. coli grown in Miller's Luria Bertani Broth nutrient medium.