What is claimed is:
1. A filtration barrier, comprising:
a nanofiber layer that includes a plurality of first nanofibers that are made of a combination of cellulose acetate (CA) and polyethylene oxide (PEO); and
a biocide layer that attaches to the nanofiber layer, and that includes a biocide and a plurality of second nanofibers that are made of the combination of the CA and the PEO,
wherein the biocide accounts for 0.5%-2% by weight in the biocide layer.
2. The filtration barrier of claim 1 , wherein the biocide covalently binds to the second nanofibers by a cross-linker.
3. The filtration barrier of claim 1 , wherein the biocide binds covalently to the second nanofibers by a cross-linker, and the cross-linker is organic titanate (TTE).
4. The filtration barrier of claim 1 , wherein the biocide is chlorhexidine (CHX).
5. The filtration barrier of claim 1 , wherein the CA accounts for 10%-20% by weight of the combination of the CA and the PEO.
6. The filtration barrier of claim 1 , wherein the PEO accounts for 0.05%-0.2% by weight of the combination of the CA and the PEO.
7. The filtration barrier of claim 1 , wherein the nanofiber layer bears positive electrostatic charges.
8. The filtration barrier of claim 1 , wherein the biocide layer includes a porosity of 90-98%.
9. The filtration barrier of claim 1 , wherein a diameter of the first nanofibers in the nanofiber layer is in a range of 50-700 nanometer (nm), and a diameter of the second nanofibers in the biocide layer is in a range of 100-900 nm.
10. The filtration barrier of claim 1 , wherein the filtration barrier includes a plurality of the biocide layers and a plurality of the nanofiber layers.
11. The filtration barrier of claim 1 , wherein the biocide layer and the nanofiber layer are assembled with a nonwoven layer that includes polypropylene meltblown microfibers.