Synthesis of cellulose aerogel beads from agricultural residues

Abstract

Academia and industry have been developing ways to produce novel materials from renewable bio-based sources. The plants hemp and flax are cultivated mainly for fibre production due to their outstanding durability, absorbency, anti-mildew and anti-microbial activity. A simple method to extract high-grade cellulose from hemp and flax waste fibres was established through alkali hydrolysis and bleaching. The quality of extracted cellulose was analysed by powder XRD and FTIR data. Cellulose solution was prepared by dissolution method using a mixture of NaOH, urea and water as solvent. We have been developing strategies to produce aerogel beads from waste hemp and flax fibres and study its up-scaling using the JetCutter® technology. Optimal parameters such as cellulose concentration, acidic regeneration bath and operational conditions of the JetCutter® were analysed and production of highly porous aerogel beads was accomplished, from commercial and extracted cellulose. The produced cellulose aerogels were characterized by nitrogen adsorption-desorption isotherm, BJH pore data analyses, density analyses, FTIR and scanning electron microscopy. Limitations still exist regarding the creation of a continuous production system. In conclusion, large quantities of this highly porous product can be produced from waste cellulose using the JetCutter®, fulfilling the first steps for its sustainable industrial production.