Inactivation of E. Coli Using ZnO and UV-LED Technology: A Promising Approach for Water Treatment

This study aims to evaluate the efficacy of advanced oxidation processes, in particular photocatalysis combined with ultraviolet light from light-emitting diodes (UV-LEDs), to inactivate Escherichia coli bacteria (strain ATCC 8739). The innovation of this research lies in the use of zinc oxide (ZnO) obtained from the recycling of zinc-carbon batteries, a sustainable alternative that has been little explored in bacterial disinfection applications. In addition, a log-linear kinetic model with tail effect is used to describe the inactivation process, evaluating the effectiveness of different ZnO concentrations (0%, 0.1%, 0.2% and 0.6%) under UV irradiation at 365 nm in a collimated system, with an exposure time of 15 minutes in all cases. The results show that recycled ZnO in combination with UV-LED light is effective in disinfection, achieving an inactivation of 3 log in 15 minutes with a concentration of 0.6% ZnO. This approach represents an important contribution to the field of photocatalysis for water treatment, proposing a sustainable technology that can have a relevant impact in the context of smart and sustainable cities.