Inactivation of E. coli in water employing Fe-TiO2 composite incorporating in-situ dual process of photocatalysis and photo-Fenton in fixed-mode

Abstract

Applications of Fe-TiO2 composite incorporating in-situ dual effect of photocatalysis and photo-Fenton process was studied for inactivation of E. coli K12 strain. A thin film of TiO2 was coated on spherical composite beads (leading to photocatalysis) comprising of clay, foundry sand (FS) and fly ash (FA) from which iron leached out (leading to photo-Fenton) thus incorporating dual effect. Operating parameters such as UV light intensity, size of beads, addition of oxidant, buffer, and area/volume ratio of the reactor were optimized for the inactivation of E. coli. In dual process, 6.2 E. coli log reduction was observed in 90 min of reaction time. An increase of 26 % of synergy with dual process was obtained in comparison to photocatalysis and photo-Fenton alone. The beads were proved to be durable for more than 50 recycles for the inactivation of E. coli. To confirm the presence of TiO2, morphological analysis and elemental composition for fresh as well as recycled composite beads was done using SEM and EDS respectively. The activity of catalyst and presence of Fe was also checked by using XRD, FTIR, and DRS.