Removal of microorganisms from fluid samples using nanofiber filtration media
A method for removing microorganisms from liquid samples and a nanofiber containing liquid filtration medium that simultaneously exhibits high liquid permeability and high microorganism retention. Microorganisms such as bacteria, particularly B. Diminuta , are removed from a liquid by passing the liquid through a porous nanofiber containing filtration medium having a B. Diminuta LRV greater than about 9, and the nanofiber(s) has a diameter from about 10 nm to about 1,000 nm. Another method for removing microorganisms such as bacteria and Mycloplasma , includes passing the liquid through a porous nanofiber containing filtration medium having a microorganism LRV greater than about 8, and the nanofiber(s) has a diameter from about 10 nm to about 1,000 nm. The filtration medium can be in the form of a fibrous electro spun polymeric nanofiber liquid filtration medium mat.
1. A multilayer porous nanofiber containing filtration medium made by electrospinning a polymer, wherein the filtration medium exhibits full retention of Brevundimonas diminuta by size-based separation as measured in accordance with ASTM F838-83 and a liquid permeability greater than about 1000 LMH/psi, and wherein the porous nanofiber filtration medium comprises a layer comprising electrospun nanofibers having a fiber diameter from about 10 nm to about 1,000 nm and a porosity from about 80% to about 95%.
2. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the filtration medium has a thickness ranging from about 1 μm to about 500 μm.
3. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the polymer is selected from the group consisting of polyimide, aliphatic polyamide, aromatic polyamide, polysulfone, cellulose acetate, polyether sulfone, polyurethane, poly(urea urethane), polybenzimidazole, polyetherimide, polyacrylonitrile, poly(ethylene terephthalate), polypropylene, polyaniline, poly(ethylene oxide), poly(ethylene naphthalate), poly(butylene terephthalate), styrene butadiene rubber, polystyrene, poly(vinyl chloride), poly(vinyl alcohol), poly(vinylidene fluoride), poly(vinyl butylene) and copolymers, derivative compounds, or blends thereof.
4. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the polymer comprises an aliphatic polyamide.
5. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the polymer comprises a blend of polymers or copolymers.
6. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the electrospun nanofibers are disposed on a porous support.
7. The multilayer porous nanofiber containing filtration medium of claim 6 , wherein the porous support comprises one or more layers selected from the group consisting of spunbonded nonwovens, meltblown nonwovens, needle punched nonwovens, spunlaced nonwovens, wet laid nonwovens, resin-bonded nonwovens, woven fabrics, knit fabrics, paper, and combinations thereof.
8. The multilayer porous nanofiber containing filtration medium of claim 1 , wherein the porosity is about 90%.
9. A method of removing bacteria from a liquid sample comprising the steps of:
a) providing a liquid sample containing bacteria;
b) providing a multilayer porous nanofiber containing filtration medium made by electrospinning a polymer, wherein the filtration medium exhibits full retention of Brevundimonas diminuta by size-based separation as measured in accordance with ASTM F838-83 and a liquid permeability greater than about 1000 LMH/psi, and wherein the porous nanofiber filtration medium comprises a layer comprising electrospun nanofibers having a fiber diameter from about 10 nm to about 1,000 nm and a porosity from about 80% to about 95%; and
c) passing the liquid sample containing bacteria through the filtration medium resulting in retention of bacteria.
10. The method of claim 9 , wherein the filtration medium has a thickness ranging from about 1 μm to about 500 μm.
11. The method of claim 9 , wherein the polymer is selected from the group consisting of polyimide, aliphatic polyamide, aromatic polyamide, polysulfone, cellulose acetate, polyether sulfone, polyurethane, poly(urea urethane), polybenzimidazole, polyetherimide, polyacrylonitrile, poly(ethylene terephthalate), polypropylene, polyaniline, poly(ethylene oxide), poly(ethylene naphthalate), poly(butylene terephthalate), styrene butadiene rubber, polystyrene, poly(vinyl chloride), poly(vinyl alcohol), poly(vinylidene fluoride), poly(vinyl butylene) and copolymers, derivative compounds, or blends thereof.
12. The method of claim 9 , wherein the polymer comprises an aliphatic polyamide.
13. The method of claim 9 , wherein the polymer comprises a blend of polymers or copolymers.
14. The method of claim 9 , wherein the electrospun nanofibers are disposed on a porous support.
15. The method of claim 14 , wherein the porous support comprises one or more layers selected from the group consisting of spunbonded nonwovens, meltblown nonwovens, needle punched nonwovens, spunlaced nonwovens, wet laid nonwovens, resin-bonded nonwovens, woven fabrics, knit fabrics, paper, and combinations thereof.
16. The method of claim 1 , wherein the porosity is about 90%.