Visible light photocatalytic degradation of organic pollutants in industrial wastewater by engineered TiO 2 nanoparticles

The present study acknowledges a simple and effective sol–gel: doping method was used for band-gap engineering of titanium dioxide (TiO 2 ) nanoparticles at lowest temperature (40 ℃) to produce doped TiO 2 with dopants like N (nitrogen), C (carbon), Ag (silver), and Fe (iron) of different concentrations that decreased band-gap energies (i.e., > 3.2 eV) from UV range to visible range. Structural and functional properties were modulated by controlling the composition of dopants and precursors for better adsorption property and high specific surface area. Tauc-plot with UV–Vis spectrum: N (2.1 eV) > C (2.8 eV) > Ag (2.9 eV) > Fe (3.0 eV) suggested reduced band-gap energies (i.e., ≥ 3.0 eV). The photocatalytic effect was verified with the degradation of methylene blue (MB) and acid pink dye under visible light irradiation. Observation suggested that nitrogen-doped TiO 2 (N-TiO 2 ) with 2%wt. concentration has shown a higher degradation rate of 74% with respect to methylene blue in 60 min. A total of 98.4% degradation of acid pink dye (widely used in textile industry) was performed in 60 min by Fe2 (iron-doped TiO 2 with 2% wt). The doped-TiO 2 nanoparticles were also verified for their antimicrobial activity toward pathogenic strain. XRD (X-ray diffraction) revealed that the doped TiO 2 nanoparticles had attained anatase structure at a lower temperature without calcination process as compared to the reported literature.