Modification of ceramic microfilters with colloidal zirconia to promote the adsorption of viruses from water

The purpose of this study was to test the feasibility of modifying commercial microporous ceramic bacteria filters to promote adsorption of viruses. The internal surface of the filter medium was coated with ZrO2 nanopowder via dip-coating and heat-treatment in order to impart a filter surface charge opposite to that of the target viruses. Streaming potential measurements revealed a shift in the isoelectric point from pH <3 to between pH 5.5 and 9, respectively. While the base filter elements generally exhibited only 75% retention with respect to MS2 bacteriophages, the modified elements achieved a 7 log removal (99.99999%) of these virus-like particles. The coating process also increased the specific surface area of the filters from ≈2 m2/g to between 12.5 and 25.5 m2/g, thereby also potentially increasing their adsorption capacity. The results demonstrate that, given more development effort, the chosen manufacturing process has the potential to yield effective virus filters with throughputs superior to those of current virus filtration techniques.