Highly Porous Materials of Cellulose from Agricultural Residues

Abstract

Aerogels of cellulose are one of the classes open porous lightweight materials. We have acquired good experience in preparing cellulose aerogels in various dimensions such as monoliths, fibres, beads, sheets and scaffolds.1-6 With our expertise, we are developing simple and convenient methodologies to prepare cellulose aerogels from agricultural residues. The preliminary data will be presented in this conference. The raw materials of hemp and flax fibres have been converted to high grade cellulose powder by alkali/acid hydrolysis and then followed by treatment with oxidizing medium (bleaching). Cellulose wet gels have been prepared by dissolution method using molten-salt hydrate or NaOH-Urea-Water as solvent medium. The physical properties of classical cellulose aerogels will be compared with the aerogels produced from the agricultural residues. In addition, the influence of regeneration bath on physical properties of cellulose aerogels have been studied. Strong hydrochloric acid and various simple organic acids such as acetic acid, lactic acid, gluconic acid and citric acid have been employed. In comparison with the aerogels prepared from strong hydrochloric acid, homogeneous distribution of nanofibers has been observed for the samples from organic acids. All samples have been characterized by nitrogen adsorption-desorption isotherm, BJH pore data analyses, density analyses, Powder X-ray diffraction, FTIR and scanning electron microscopy.