Gelatin-reinforced cellulose nanofiber composite cryogels for effective separation of small particulate matter in air

Abstract

Herein, novel composite aerosol filters solely comprising renewable materials were designed using gelatin as a reinforcement agent and aqueous tert-butyl alcohol (TBA) as a dispersing medium for the cellulose nanofiber skeleton. The prepared composite cryogels exhibited distinct spider-web-like crosslinked structures and nanoporous architectures with porosity exceeding 98.8 % and density of less than 0.018 g/cm3. These composite filters exhibited high filtration efficiency and a robust and flexible mechanical structure due to gelatin reinforcement; furthermore, their quality factor exceeded the target threshold of 0.01 Pa−1 for 300 nm particle size. The filtration performance and mechanical properties of the composite filters could be tailored by adjusting the cellulose nanofiber (CNF), gelatin, and TBA contents, enabling the preparation of cryogels with a firm and strong structure. This study introduces ultraporous solids based on nanocellulose (NC) cryogels, which are promising, novel, and green materials for the production of advanced high-performance filter media for aerosol separation. Furthermore, the aforementioned approach is promising for the preparation of mechanically robust nanoporous biomaterials suitable for diverse applications such as heat and thermal insulation.