Photocatalytic Bacterial Disinfection using Ago/Ag+1 Immobilized on CNT Modified TiO2 nanomaterials

Abstract

Different loading of Ag nanoparticles (2 and 6%) modified TiO2 synthesized by employing polymeric template; comprises of polyvinyl alcohol and polyethylene glycol (Tev), were utilized to react hydrothermally (433 K for 48 h) with functionalized SWCNT and MWCNT. Several characterization techniques, including UV-visible diffuse reflectance spectroscopy, X-ray diffraction, HRTEM-ASED, and N2 sorptiometry were utilized for obtaining information about surface texturing, morphology, optical properties and crystalline phases. The synthesized photocatalysts were tested for their antibacterial activity against Escherichia coli (Gram negative bacterium) and Staphylococcus aureus (Gram positive bacterium) through agar well diffusion method under visible light irradiation (λ > 450 nm, 60 mWcm-2). It has been revealed that the photocatalyst TevAg6-SWCNT exhibited the maximum lethal action thereby inhibiting the growth of bacteria as compared to rest of the catalysts; this was due to increase in surface area value with delay in electrons and holes recombination as well as the diameter of Ago nanoparticles which was reduced to 3 nm. It has been evidenced that the nanocomposites attack mechanism on while disinfecting bacteria indicates the formation of O2•− and ∙OH radicals, those played significant role in inactivation of cellular process. The TEM images revealed the role of Ag+ ions, and the presence of TevAg6-SWCNT were thoroughly studied and correlated to identify the disinfection mechanisms induced through irradiation of visible light.