Facile and novel ambient pressure drying approach to synthesis and physical characterization of cellulose-based aerogels

Abstract

In this study, highly porous and ultralight cellulose aerogel (CA) was successfully synthesized via a novel and facile ambient pressure drying technique. In this drying method, naphthalene (NPH) as the porous-making agent occupied space between cellulose fibers and controlled structural collapse and severe shrinkage of samples successfully. By sublimation of NPH crystals at the end of procedure, ultimate CA was obtained. This technique can be considered as a fast, safe and cost-effective drying method. CA samples illustrated appropriate physical characteristics including: low densities (0.058 g cm−3), high porosity (> 96.5%), low thermal conductivity (0.0417 W m−1 K−1), appropriate mechanical strength and negligible shrinkage (< 10%) during the drying procedure. hydrophobic cellulose aerogel (HCA) and carbonized cellulose aerogel (CCA) were also obtained and the oil/water separation efficiency of these samples were investigated. Contact angle test reveled highly hydrophobicity with angle equal to 137° and 126° for HCA and CCA, respectively. Investigation of oils and organic solvents adsorption capacity illustrated that samples adsorbed oils and organic solvents in range from 1200 to 1800% of their weight. Regeneration ability of HCA and CCA was studied in five cycles. Depending on type of adsorbate, regeneration study showed various regeneration capacity from 30 to 98%.