Comparative Study of Titanium Dioxide and Lysozyme-Added Titanium Dioxide Nanoparticles for Enhanced Photocatalytic Degradation

Titanium dioxide (TiO₂) and lysozyme-added titanium dioxide (L:TiO₂) nanoparticles were synthesized via a hydrothermal method and comprehensively characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD analysis revealed the dominance of the anatase phase in L:TiO₂, while TiO₂ exhibited both anatase and rutile phases. FTIR spectroscopy identified specific chemical bonds or functional groups associated with lysozyme addition. UV-Vis spectroscopy indicated a decrease in the band gap energy from 3.2 to 2.9 eV upon the incorporation of lysozyme. The SEM/EDS analysis showed agglomerated fine particles with the presence of Ti, O, and C elements. The TEM analysis confirmed an average particle size of 12 nm for L:TiO₂ and 21 nm for TiO₂ nanoparticles, consistent with the XRD results. Furthermore, the photocatalytic activity of both TiO₂ and L:TiO₂ nanoparticles was evaluated for the degradation of methylene blue (MB) and methyl orange (MO) dye. L:TiO₂ nanoparticles exhibited superior photocatalytic performance, degrading MB dye to 97% and MO to 81% within a 90-minute time interval under UV irradiation at 365 nm, compared to 90% and 76% degradation, respectively, using TiO₂ nanoparticles. Optimization studies revealed that the best degradation efficiency was achieved at a dosage of 0.1 gm. These results demonstrate the enhanced photocatalytic activity of lysozyme-added TiO₂ nanoparticles, underscoring their potential for environmental remediation and water purification applications.