Factors Affecting Microbial Resistance to Advanced Oxidation Processes in Water-Borne Bacterial Disinfection

Advanced oxidation techniques have been researched and suggested as an alternative to conventional disinfection where photocatalytic titanium dioxide nanoparticles show great promise as an antimicrobial agent for water treatment applications. In the application of this material, ultraviolet radiation photoactivates the nanoparticles, leading to the production of reactive oxygen species (ROS) and subsequent destruction of microbial cells through potent oxidative reactions. Although extrinsic variables to maximize the effectiveness of the process, such as effective nanoparticle concentration and UV light intensity can be standardized for application, intrinsic variation in microorganisms and oxidative barriers can limit the effectiveness of this disinfection procedure. In this study, the intensity of UV-A radiation was varied and applied to different concentrations of n-TiO2 in a bacterial suspension to elucidate the impact of these variables on the efficacy of TiO2 enhanced pathogen disinfection. Additionally, the effect of a radical scavenger was tested to determine how these reactions may limit the effectiveness of this disinfection practice. To visualize the physical interaction between pathogen and nanoparticle, TEM images were acquired to inspect the physiological condition of the microorganism before and after the disinfection process.