US 12,304,972 B2
Cellulose-containing filtration materials and methods of making the same
Peter N. Ciesielski, Arvada, CO (US); Michael E. Himmel, Littleton, CO (US); and Todd Brian Vinzant, Elizabeth, CO (US)
Assigned to Alliance for Sustainable Energy, LLC, Golden, CO (US)
Filed by Alliance for Sustainable Energy, LLC, Golden, CO (US)
Filed on Sep. 16, 2021, as Appl. No. 17/477,195.
Claims priority of provisional application 63/201,002, filed on Apr. 8, 2021.
Claims priority of provisional application 63/078,975, filed on Sep. 16, 2020.
Prior Publication US 2022/0081490 A1, Mar. 17, 2022
Int. Cl. C08B 15/10 (2006.01); B01D 39/16 (2006.01); B82Y 40/00 (2011.01); D06M 15/05 (2006.01); D06M 15/71 (2006.01); D06M 15/715 (2006.01)
CPC C08B 15/10 (2013.01) [B01D 39/1615 (2013.01); D06M 15/05 (2013.01); D06M 15/71 (2013.01); D06M 15/715 (2013.01); B01D 2239/0258 (2013.01); B01D 2239/0654 (2013.01); B82Y 40/00 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A composite comprising:
a woven cotton fabric having an outer surface and a thickness; and
a plurality of cellulose nanofibers in physical contact with the outer surface, wherein:
the cellulose nanofibers penetrate into at least a portion of the thickness of the woven cotton fabric,
the cellulose nanofibers are present on the woven cotton fabric at a loading between 0.01 mg and 1 mg per square centimeter of woven cotton fabric,
the woven cotton fabric comprises a plurality of hydroxyl groups bonded to the outer surface,
the cellulose nanofibers are at least partially bonded to the woven cotton fabric by hydrogen bonding between the hydroxyl groups and the cellulose nanofibers,
the composite has an average filtration efficiency of less than or equal to 90% for particles having a characteristic length between about 50 nm and about 100 μm, and
the composite is characterized by an average inhalation resistance of less than or equal to 35 mm H2O as measured across the thickness and the material.