Impact of Silver Ions Doping and Calcination on the Physicochemical Characteristics of TiO2 Nanoparticles with Photocatalytic and Regeneration Potential

Visible light-driven Ag^+ doped TiO2 photocatalysts were successfully prepared with modified low-cost Liquid Impregnation (LI) method yielding up to 95 % product. The native and newly synthesized photocatalysts were calcined at various temperatures and characterized using diffused reflectance spectroscopy (UV/Vis-DRS), XRD, XPS, TEM, EDX, XRF, and pHPZC analyses. The XRD results for all samples revealed that the anatase phase was dominant at all calcination temperatures. The Ag^+ doping reduced the bandgap energy to 2.88 eV, which significantly enhanced the photocatalytic efficiency towards Methylene Blue (MB) under compact fluorescent light. The photocatalytic efficacy of the nano-catalysts was also tested using a binary solution containing a model dye (MB) and Cd^2+ under ordinary compact fluorescent light. The presence of competitive ions i.e. Cd^2+ increased the MB degradation up to 4 folds under the ambient conditions whereby the maximum amount of MB adsorbed by nano-catalysts reached 46 mg/g. The high-temperature combustion method was found more effective for the regeneration of TiO2 photocatalysts compared to the chemical regeneration. The reusable character of the regenerated samples posed a significant impact on the current work to be applied in wastewater treatment in bulk.