Photocatalytic inactivation of Vibrio fischeri using Fe₂O₃-TiO₂ -based nanoparticles

Biofouling is a major problem in water membrane processes, especially in seawater reverse osmosis plants. Inactivation of Vibrio fischeri (a well-known marine bacterium forming biofilm) through photocatalysis via visible light was investigated in this work using active Fe2O3-TiO2 nanoparticles. Five Fe2O3-TiO2 photocatalysts with different weight percentage of Fe2O3 (0–5 wt%) were synthesized using an ultrasonic-assisted co-precipitation method.

The photocatalysts were characterized by powder X-ray diffraction (XRD), BET surface area, transmission electron Æ (TEM) plus selected area electron diffraction (SAED) patterns, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and diffuse-reflectance spectroscopy (DRS).

Based on the design of experiments, the synthesized photocatalysts were tested for inactivation of V. fischeri under visible light irradiation at different temperatures (25–35 °C) and different photocatalyst dosage (0.1–2 g/L). The photocatalytic microbial inactivation experiments were performed in artificial seawater appropriate for growth of the marine bacterium.

The results revealed that the highest inactivation efficiency of V. fischeri was achieved when 1 g/L of 2.5 wt% Fe2O3-TiO2 were used, at 35 °C. Photocatalytic inactivation of microorganisms using visible light-driven Fe2O3-TiO2 photocatalysts, could introduce an innovative green method in pretreatment units of reverse osmosis plants to control the membrane biofouling.