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Fouling due to biofilms composed primarily of microorganisms and extracellular polymeric substances is a significant hindrance to membrane filtration in water treatment. The goal of this work was to use a reactive membrane surface to reduce membrane biofouling by coating a ceramic ultrafiltration membrane with the nanoparticulate photocatalyst, TiO2. 10-Day biofilm growth experiments were conducted to determine the effect of photocatalytic coatings on the formation of a Pseudomonas putida biofilm and subsequent changes in membrane flux. Results indicate that a highly hydrophilic, photoreactive coating of mixed phase TiO2 nanoparticles is effective for the control of biofouling on ceramic ultrafiltration membranes.

Bacterial attachment is an initial stage in biofilm formation that leads to flux decline in membrane water filtration. This study compares bacterial attachment among three photocatalytic ceramic ultrafiltration membranes for the prevention of biofilm formation. Zirconia ceramic ultrafiltration membranes were dip-coated with anatase and mixed phase titanium dioxide photocatalysts to prevent biofilm growth. The membrane surface was characterized in terms of roughness, hydrophobicity, bacterial cell adhesion, and attached cell viability, all of which are important factors in biofilm formation. The titanium dioxide coatings had minimal impact on the membrane roughness, reduced the hydrophobicity of membranes, prevented Pseudomonas putida attachment, and reduced P. putida viability. Degussa P25 is a particularly promising reactive coating because of its ease of preparation, diminished cell attachment and viability in solutions with low and high organic carbon concentrations, and reduced flux decline. These reactive membranes offer a promising strategy for fouling resistance in water filtration systems.