Virus removal and inactivation in a hybrid microfiltration–UV process with a photocatalytic membrane

• First application of photocatalytic membranes for virus removal and inactivation.
• Bacteriophage P22 is used as a model virus.
• Original design couples outer surface of a tubular membrane with UV light.
• Hybrid photocatalytic UV–microfiltration process is effective in inactivating virus.
• Potential applications include treatment of high flow rate, turbid streams.

The study describes the first application of photocatalytic membranes for virus removal and inactivation. In the proposed hybrid treatment process, a UV lamp and a microfiltration membrane are positioned in foci of two parabolic reflectors facing each other and UV light is focused on a photocatalyst-coated outer surface of the microfilter. The ceramic tubular membrane (nominal pore size of 0.8 μm) is operated in an inside-out geometry. To evaluate virus removal and inactivation efficiency of the hybrid photocatalytic microfiltration–UV process, bacteriophage P22 is used as a model virus. The kinetics of P22 inactivation by direct UV is found to fit Collins–Selleck model with the coefficient of specific lethality ΛCSΛCS = 1.972. Batch UV disinfection and crossflow filtration tests with membranes coated or uncoated with a layer of photocatalyst show that the hybrid photocatalytic microfiltration–UV process is considerably more effective in inactivating the virus (LRV = 5.0 ± 0.7) than the constituent processes – UV disinfection and microfiltration – applied in series (aggregate LRV = 2.0 ± 0.5) or together but without the photocatalytic coating on the membrane (LRV = 2.4 ± 0.2). Potential applications of the proposed treatment process include disinfection of turbid, high fouling potential and high flow rate streams.

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