CATIONIC CHARGE MODIFIED FILTER MEDIA AND USE THEREOF

The media comprises cellulosic fiber and silica based particulate or fiber filter elements and a charge modifying amount of a cationic charge modifying system bonded to the surfaces thereof. A component of the charge modifying system is a primary charge modifying agent characterized as a water soluble organic polymer capable of being adsorbed into the filter elements and having a molecular weight greater than about 1000. Each monomer of the polymer can have at least one epoxide group capable of bonding to the surface of the filter elements and at least one quaternary ammonium group. Preferably, the primary charge modifying agent is a polyamido-polyamine epichlorohydrin resin, a polyamine epichlorohydrin resin, or a resin based upon diallylnitrogen-containing materials reacted with epichlorohydrin. A portion of the epoxy groups on the organic polymer are bonded to the secondary charge modifying agent. This secondary charge modifying agent is an aliphatic polyamine having at least one primary amine or at least two secondary amines.