Mechanisms of Viral Capture by Microfiltration

The male-specific bacterial virus MS2 is being used in this study to investigate the mechanisms of virus capture from aqueous suspension by a polypropylene microfilter. Mechanisms being studied include 1) adsorption of viruses to clean, unused filters; 2) adsorption of viruses to used filters; 3) capture of particulates formed from virus complexation with organic or inorganic materials; and 4) entrapment of viruses by a barrier layer generated by these materials on the outer surface of the filter. Batch studies were conducted using chopped filter material to quantify virus adsorption to unused filters. Identical studies are planned to examine used filters. Constant pressure studies using manufactured filter modules will be performed to assess the importance of complexation and barrier layer formation. Ranges of values of solution pH and ionic strength are to be examined in combination with varied concentrations of inorganic suspended solids, organic suspended solids and dissolved organic material to determine method and extent of virus capture. Initial data show adsorption directiy to an unused filter surface to be negligible between pH3 and pH10. Data is being collected to quantify the relative contribution of each of the other three mechanisms.