N, Ag co-doped TiO2 mediated modified in-situ dual process (modified photocatalysis and photo-Fenton) in fixed-mode for the degradation of Cephalexin under solar irradiations.

Novel FeNAgTiO2 composite beads possessing unusual characteristics of modified in-situ dual process (modified photocatalysis and photo-Fenton) resulted in reduction in treatment time of Cephalexin (CEX). These composite beads were prepared using NAgTiO2 and waste foundry sand (FS) and fly-ash (FA) as alternative source of iron. The modified TiO2 was characterized through SEM/EDS, DRS, XRD, TGA, FTIR, XPS and Raman spectroscopy to affirm the distribution of Ag and N on TiO2 surface. The modified in-situ dual process using FeNAgTiO2 composite beads yielded 77% degradation of CEX after 60 min of solar irradiations with overall synergy of 24% over individual processes. FeNAgTiO2 composite beads were characterized through SEM/EDS, XRD and DRS to confirm the presence of Fe along with Ag, N and TiO2 on the surface of beads. These composite beads were stable and active even after 15 recycles. The mineralization of CEX was validated through reduction in COD and TOC along with generation of anions while intermediates were identified through GC-MS analysis.