Microporous filter media, filtration systems containing same, and methods of making and using

A composite filter medium comprising:

• as adsorbent prefilter having immobilized therein a material capable of removing charge-reducing contaminants;
• a microporous structure, disposed downstream from said adsorbent layer, comprising a plurality of nanofibers, said microporous structure having a mean flow path of less than about 0.6 micron;
• and
• a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on at least a portion of a surface of at least some of the plurality of fibers of said microporous structure.

A filter system comprising:

• a granular bed of particles capable of removing charge-reducing contaminants;
• a microporous structure, disposed downstream from said granular bed, having a mean flow path of less than about 0.6 micron;
• and
• a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on, at least a portion of a surface of said microporous structure.

A filter system comprising:

• a solid composite block comprising a material capable of removing charge-reducing contaminants;
• a microporous structure, disposed downstream from said block, having a mean flow path of less than about 2.0 microns;
• and
• a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on at least a portion of a surface of said microporous structure.

A process for making a filter medium comprising the steps of:

• providing a plurality of nanofibers;
• coating at least a portion of a surface of at least some of the plurality of nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex;
• and
• forming said fibers into a microporous structure having a mean flow path of less than about 1 micron.

A process for making a filter medium comprising the steps of:

• providing a plurality of polymer nanofibers;
• coating at least a portion of a surface of at least some of the plurality of polymer nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex;
• and
• forming a microporous structure having a mean flow path of less than about 1 micron.

A process for making a filter medium comprising the steps of:

• providing a plurality of cellulose nanofibers;
• coating at least a portion of a surface of at least some of the plurality of cellulose fibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex;
• and
• forming a microporous structure having a mean flow path of less than about 1 micron.

A process for making a filter medium comprising the steps of:

• providing a plurality of nanofibers;
• coating at least a portion of a surface of at least some of the plurality of said nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a silver-amine-halide complex having a medium to high charge density and a molecular weight greater than 5000 Daltons;
• and
• forming a microporous structure having a mean flow path of less than or about 0.6 microns. providing an adsorbent prefilter comprising a material capable of removing charge-reducing contaminants from an influent, and placing said adsorbent prefilter upstream of said microporous structure.

A process for making a filter system comprising the steps of:

• providing an adsorbent prefilter comprising a material capable of removing charge-reducing contaminants from an influent, wherein the material is immobilized into a solid composite block;
• providing a plurality of nanofibers;
• coating at least a portion of a surface of at least some of the plurality of said nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a silver-amine-halide complex having a medium to high charge density and a molecular weight greater than 5000 Daltons;
• and
• forming a microporous structure having a mean flow path of less than or about 0.6 microns.

A method of removing microbiological contaminants in a fluid comprising the steps of:

• providing a filter medium having a microporous structure having a mean flow path of less than about 1 micron, the microporous structure having coated on at least a portion thereof a microbiological interception enhancing agent comprising a cationic metal complex wherein said cationic material has a medium to high charge density and a molecular weight greater than about 5000 Daltons;
• contacting the fluid to the filter medium for greater than about 3 seconds;
• and
• obtaining at least about 6 log reduction of microbiological contaminants smaller than the mean flow path of the filter medium that pass through the filter medium.

A gravity-flow filtration system for treating, storing, and dispensing fluids comprising:

• a first reservoir for holding a fluid to be filtered;
• a filter medium in fluid communication with said first reservoir, said filter medium comprising a microporous structure with a mean flow path of less than about 1 micron, and wherein said filter medium is so treated as to provide at least about 4 log reduction of microbiological contaminants smaller than the mean flow path of said filter medium;
• and
• a second reservoir in fluid communication with said filter medium for collecting a filtered fluid.