High virus retention mediated by zirconia microtubes with tailored porosity

In this study the fabrication of zirconia microtubes for virus filtration using a sequence of slurry preparation, extrusion process, debinding and final sintering is presented. The sintered zirconia microtubes are characterised by microstructural analysis including Hg intrusion porosimetry, BET analysis and three-point bending tests. Zirconia microtubes sintered at 1050 °C are found to provide membrane properties featuring an open porosity of 50.7% with pore sizes in the range of 10–40 nm, a specific surface area of 23.2 m2/g and an average bending strength of 32.9 MPa, being suitable for virus filtration. Based on these mesoporous microtubes water permeate fluxes of 45 L/m2 h are provided in dead-end filtration mode. A virus retention of 99.9999% (log reduction value of 6) for small bacteriophages MS2 and PhiX174 which served as surrogates for human pathogenic viruses is achieved in this study demonstrating a stable ceramic membrane with high viral retention properties.