Characterization of alkaline acid-treated fiber of Arundo donax L. from mature and immature plants: a comparative study

The present investigation aims to understand the impact of plant age and chemical treatment on quantitative and qualitative attributes of A. donax fiber. Results indicate that the age of the plant showed distinctive variation in the chemical composition and morphology of fibers obtained after chemical treatment. The percentage removal of lignin and hemicellulose was measured as 13.3% and 12.1% in immature fibers after chemical treatment led to higher cellulose content and density. However, insignificant differences were evident in terms of ash mass fraction, moisture content, extractives, and water absorption. XRD analysis showed that the chemical treatment enhanced the crystallite size by 112% in immature fibers. Moreover, TGA indicates that the immature fibers showed improved thermal stability and resistance to decomposition after chemical treatment. The chemical treatment enhanced the temperature from 250 to 300 °C to derivatize the chemical constituents of fibers. Simultaneously, the FTIR spectroscopy emphasized that with increasing reaction time more hemicellulose and lignin were removed which was accompanied by a prominent transition of functional groups after chemical treatment in the immature fibers. SEM analysis revealed alteration of fiber surface morphology, removal of impurities, increased porosity, and surface area. Simultaneously, EDX analysis showed a significant reduction in the atomic percentage of Si, Cl, and K in both types of fibers.