| Porous ceramic membranes are ideal candidates for use in environmental treatment and remediation. Ceramic membranes have a high chemical and thermal stability, allowing for aggressive cleaning and increased life span compared with polymeric membranes. For the same reasons, they are often used as substrates in photocatalytic membrane reactors. A multitude of techniques have been proposed to fabricate these photocatalytic membranes. In this study, Layer-by-layer self-assembly (LbL) and plasma enhanced chemical vapor deposition (PECVD) were used to create photocatalytic TiO2 coatings on the support structure of ceramic disc microfiltration membranes. The resulting photocatalytic layers did not measurably reduce the membrane permeability. The LbL coated membrane degraded methylene blue at a higher rate compared to the PECVD coated membrane during UV filtration experiments. By assuming a plug flow reactor (PFR) model and normalizing the measured PFR rate constant by the catalytic efficiency of each catalyst, it is evident the LbL fabricated membrane benefited from the high catalytic efficiency of the Degussa P25 photocatalyst. Additionally, the LbL fabricated membrane's efficiency at inactivating MS2 and P22 bacteriophages was tested. While P22 was inactivated at a higher rate in batch reactors, MS2 was more susceptible to inactivation during UV dead-end filtration, with a maximum log removal value (LRV) of 4.9 achieved at the flow rate of 4x10-3 liters per minute for MS2 and only 1.6 LRV of P22 at the lower flow rate 3x10-3 liters per minute. With the coating on the permeate side of the membrane, this approach to virus inactivation is particularly promising in applications to waters with high degree of turbidity. |
