Extraction and characterization of celluloses from various plant byproducts

Celluloses were extracted from teff straw (TS), enset fiber (EF), sugarcane bagasse (SB) and coffee hull (CH), agro-industrial byproducts generated in large quantities in Ethiopia. The present study aimed to explore these plant byproducts as alternative sources of cellulose for potential industrial applications, using various eco-friendly chlorine-free treatment conditions to obtain an optimum cellulose extraction condition. The byproducts and the as-extracted celluloses were analyzed for chemical compositions, yield, chemical functionality, crystallinity, thermal stability and morphology. EF yielded the highest cellulose content (60.0%), whereas CH the least (35.5%). FTIR spectra and ESEM morphological studies of the celluloses indicated progressive removal of non-cellulosic constituents. XRD analyses showed EF cellulose had the highest crystallinity index (CrI) (85.56%), crystallite size (5.52 nm), and proportion of crystallite interior chains of 200 plane (0.629), exhibiting unique physicochemical properties. The byproducts and the as-extracted celluloses showed Cellulose I_β crystal lattice, while celluloses from EF and SB also displayed (partial) polymorphic transition into Cellulose II. TGA studies revealed enhanced stability of the as-extracted celluloses. On the basis of the physicochemical characteristics of the celluloses, all the byproducts studied could be considered as alternative sources of cellulose for potential value-added industrial applications.