Sterilization of Escherichia coli by using near-UV LED and TiO₂ nanofibers that were prepared by using electrostatic spray

TiO₂ nanofiber films were prepared by a homemade electrostatic spray method at 13 kV using a high power supply. As-prepared TiO₂ was used to sterilize enteropathogenic Escherichia coli in polluted water by using near-UV LEDs at three different wavelengths with variable exposure time and frequency of irradiation. Irrespective of the wavelength of the light source used, longer irradiation times such as 1 h completely inactivated the E. coli. However, a wavelength of 375 nm was effective in inactivating in a shorter irradiation time (15 min). When the frequency of irradiation was 1 kHz, almost 95% of the E. coli was inactivated after 30 min exposure.