Virus Adsorption to Microporous Filters Modified by in situ Precipitation of Metallic Salts

Microporous and depth filters composed of fiberglass, cellulose, and nitrocellulose were placed in solutions of soluble metallic salts such as ferric chloride. Following adsorption of the soluble salt, the filters were allowed to dry and then placed in a solution of sodium or ammonium hydroxide. This resulted in the formation of stable precipitates in and around the fibers of the filters. Filters modified by this procedure of insitu precipitation adsorbed significantly more viruses than untreated filters. Filters modified by the insitu precipitation of combinations of salts such as ferric and aluminum or magnesium generally were better virus adsorbers than filters modified by the precipitation of a single salt.