Photocatalytic Degradation of Methylene Blue Dye in Wastewater Using Iron-Doped Titanium Dioxide Nanoparticles.

Abstract

The photocatalytic degradation of methylene blue dye in wastewater was investigated using iron (III)-doped titanium dioxide nanoparticles. The nanoparticles were synthesized via the sol-gel method and calcined at a temperature 450°C for 2 hours. The synthesized nanoparticles were characterized using Scanning Electron Microscope and Energy Dispersive Spectroscopy (SEM-EDS) to determine the shape, elemental composition, and area of the nanoparticles, X-ray diffraction (XRD) provided information on diffraction peaks, crystal planes, and average particle sizes, and ultraviolet-visible spectroscopy (UV-Vis) was used to determine the absorbance and energy band gap. The SEM-EDS analyzed iron-doped TiO2 has uniform spherical particles with surface area 0.052 m2/g compared to 0.003 m2/g for TiO2. XRD analysis indicated that crystallite average size of 11.5 nm for Fe-TiO2 and TiO2 has average crystallite size was 15.6 nm. UV-Vis determined the energy bandgap of iron-doped TiO2 nanoparticles to be 2.15 eV at and TiO2 nanoparticles 2.80 eV. Optimization of the photocatalytic degradation process was performed by varying the pH, contact time, initial dye concentration, and catalyst dosage. This was done by utilizing different irradiation sources such as visible LED light (2643 lux, 20 watts) and visible light (fluorescent, 674 lux, 10 watts) in a fabricated photoreactor system. The optimized degradation percentage of methylene blue dye using iron-doped TiO2 nanoparticles under LED and fluorescent visible light irradiation were 95.8% and 84.2% respectively. While, the degradation percentage of methylene blue dye using only TiO2 nanoparticles under LED and fluorescent visible light irradiation were 80.2% and 72.1% respectively. Hence, comparing the results of the LED light irradiation with those of visible light, it was observed that the photocatalytic degradation efficiency was higher under LED light using Fe-doped TiO2. The optimized parameters under LED irradiation were applied to river environmental water samples (A and B) collected, resulting in degradation percentages of 86.2% for sample A and 81.8% for sample B using Fe-TiO2. Therefore, the study provides valuable insights of the synthesis, characterization, optimization parameters, the potential of iron-doped titanium dioxide nanoparticles as an effective photocatalyst for the degradation of methylene blue dye in wastewater and its potential applications in water treatment and environmental remediation.