METAL TREATMENTS FOR FIBER SUBSTRATES, PROCESSES FOR TREATING FIBER SUBSTRATES, AND FILTER MEDIA HAVING TREATED FIBER SUBSTRATES

Processes for increasing an affinity of a filter media to airborne viral particles. A fiber substrate comprising borosilicate is provided. The fiber substrate may comprise acidic functional groups. A metal salt solution is introduced to the fiber substrate to form a treated substrate. The metal salt solution includes divalent and/or trivalent metal cations. The pH of the metal salt solution is adjusted, and a divalent and/or trivalent metal cation is exchanged with a proton from the acidic functional groups. The metal may be present in an amount ranging from about 0.001 to about 3.0 wt. % of the treated fiber substrate. The treated fiber substrate is incorporated into a filter media before or after the deposition of the metal onto the fiber substrate.