title: Simple Freeze-Drying Procedure for Producing Nanocellulose Aerogel-Containing, High-Performance Air Filters.
abstract: Simple freeze-drying of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibril (TOCN) dispersions in water/tert-butyl alcohol (TBA) mixtures was conducted to prepare TOCN aerogels as high-performance air filter components. The dispersibility of the TOCNs in the water/TBA mixtures, and the specific surface area (SSA) of the resulting TOCN aerogels, was investigated as a function of the TBA concentration in the mixtures. The TOCNs were homogeneously dispersed in the water/TBA mixtures at TBA concentrations up to 40% w/w. The SSAs of the TOCN aerogels exceeded 300 m2/g when the TBA concentration in the aqueous mixtures was in the range from 20% to 50% w/w. When a commercially available, high-efficiency particulate air (HEPA) filter was combined with TOCN/water/TBA dispersions prepared using 30% TBA, and the product was freeze-dried, the resulting TOCN aerogel-containing filters showed superior filtration properties. This was because nanoscale, spider-web-like networks of the TOCNs with large SSAs were formed within the filter.
authors: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo 113-8657, Japan.|Central Research Laboratory, Hokuetsu-Kishu Paper Co. Ltd. , 3-5-1, Nishizao, Nagaoka, Niigata 940-0027, Japan.
authors: Junji
authors: J
authors: Nemoto
authors: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo 113-8657, Japan.
authors: Tsuguyuki
authors: T
authors: Saito
authors: Department of Biomaterials Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo , Tokyo 113-8657, Japan.
authors: Akira
authors: A
authors: Isogai
keywords: aerogel; air filter; freeze-drying; nanocellulose; specific surface area