Synthesis and Characterization of Cellulose Nanocrystals from Cottonseed Hulls Using Acid Hydrolysis and Ultrasonication

Abstract

Cottonseed hulls are abundant byproducts of the cottonseed oil industry and are rich in cellulose fibers (30-50 %). In this research, cellulose nanocrystals were synthesized from cottonseed hulls via acid hydrolysis followed by ultrasonication. We investigated two acid concentrations (50 % and 60 % (v/v)) and ultrasound amplitudes (30 % and 50 %) in the synthesis of cellulose nanocrystals. The effects of treatment conditions on the physical, thermal, and structural properties were assessed using Fourier Transform Infrared Spectroscopy, X-ray diffraction spectroscopy, Differential Scanning Calorimetry, and Field Emission Scanning Electron Microscopy. The FESEM results showed fiber-like structures in the range of 100- 200 nm. The results revealed that the synthesis conditions significantly (p<0.05) affected particle size and structural properties, and that the ultrasound treatment helped reduce the acid concentration and obtain uniform cellulose nanofibers. The obtained nanofibers found diverse applications in food packaging, biomedical, waste-water purification, and textiles industries, etc.