Effects of operational parameters on bacterial inactivation in Vis-LEDs illuminated N-doped TiO2 based photoreactor

[Display omitted] •The photoreactor was developed from immobilized nitrogen-doped titanium dioxide.•The reactor performance has been investigated under different operational parameters.•The reactor efficiency was increased with increasing TiO2 load and photon flux.•The reactor efficiency was decreased with increasing E. coli load and flow rate. Titanium dioxide (TiO2) based photocatalysis has been widely investigated for several applications in the past. The major challenges related to this catalyst have also been successfully tackled through doping and immobilization techniques. For the practical application of the TiO2 photocatalyst in environmental remediation, the selection and design of proper types of photoreactors are also mandatory. The present study focuses on the investigation of operational parameters of a new type of Vis-LEDs illuminated N-doped TiO2 based photoreactor developed from immobilized visible light active nitrogen-doped titanium dioxide on the surface of glass beads. Advanced instruments, such as HR-TEM, XRD, BET, XPS, UV-Vis, FE-SEM, FT-IR, and TGA-DSC were employed to characterize the prepared catalyst. The performance of the photoreactor has also been investigated under different operational parameters (such as TiO2 load, initial E. coli concentration, bacterial solution feed flow rate, and light incident photon flux). Results showed that the inactivation efficiency of the reactor was found to increase with increasing TiO2 load and incident photon flux. However, the efficiency of the reactor decreased with increasing E. coli concentration and bacterial solution flow rate. The results indicate that initial E. coli concentration of 106 CFU mL-1, TiO2 concentration of 0.6 g, a flow rate of 40 mL min-1 and light incident photon flux of 5.23 × 1016 photons/s demonstrated higher inactivation efficiency in comparison to other study parameters. The photocatalytic inactivation kinetics also best fitted to Modified-Hom model with R2 0.9998.