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 band gap 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 Cd2+ under ordinary compact fluorescent light. The presence of competitive ions i.e. Cd2+ increased the MB degradation up to 4 folds under the ambient conditions whereby the maximum amount of MB adsorbed by nano-catalysts reached to 46 mg/g. The high temperature combustion method was found more effective for the regeneration of TiO2 photocatalysts compared to the chemically regeneration. The reusable character of the regenerated samples posed a significant impact of the current work to be applied in wastewater treatment in bulk.