Photocatalytic-based inactivation ofE. coliby UV 282 nm XeBr Excilamp

Abstract

The impact of suspended TiO2 particles on the efficiency of UV inactivation of E. coli by XeBr excilamp (282 nm) was assessed using direct and integrating sphere spectroscopy for absorbance measurements in the calculations of UV doses. Complete disinfection (no quantifiable E. coli colonies) was observed at 30 (0.25 g/L of TiO2) and 40 mJ/cm(2) (0.1 g/L of TiO2), whereas UV alone and the treatment in the presence of 0.5 g/L of TiO2 produced tailing in the dose-response curves. The optimum concentration of TiO2 was found to be 0.25 g/L, which correlates with the highest •OH exposure (CT value) and steady state concentration of •OH. This study demonstrates the importance of proper calculation of UV dose and inclusion of •OH exposure effects when reporting results from disinfection studies using technologies with multiple modes of inactivation such as with UV/TiO2.

Recycling of Glass Waste by Deposition of TiO2 for the Intensification of the Photocatalytic Effect in the Purification of Wastewater

“…Escherichia coli is one of the most widely used biological expression systems for experimental research because it is easy to cultivate and has a short cell life cycle. The cellular components of microorganisms are composed of organic complex substances, and exposure to reactive oxygen species, e.g., O 2 − and HO − generated through photocatalysis, can lead to oxidative damage on their cell membranes [20][21][22][23][24], DNA and RNA [25][26][27].…”

Inactivation of bacteria via photosensitization of vitamin K3 by UV-A light

“…Other beneficial uses of UV light and photosensitizers include inactivation of microorganisms that contaminate food, air, and water, and decontamination of clinical environments to minimize transfer of microorganism-based diseases (Hamamoto et al, 2007;Matafonova & Batoev, 2012;Carrascosa et al, 2013). A combination of short wave UV light radiation with H 2 O 2 or TiO 2 can inactivate bacteria in suspension through an advanced oxidation process that produces strong oxidizing species, predominantly hydroxyl radicals (Matafonova et al, 2008(Matafonova et al, , 2013Matafonova & Batoev, 2012;Rubio et al, 2013). UV light has also been used in combination with specific exogenous photosensitizers such as UV-A-riboflavin for photochemical therapy for bacterial keratitis (Makdoumi et al, 2012) and UV-A with a synthetic photosensitizer, amino-psoralen, (amotosalen HCl, also known as S-59), for pathogen reduction of platelet and plasma blood components (Irsch & Lin, 2011).…”