Characterization of Pearl Millet (Pennisetum glaucum) waste

Abstract Environmental considerations in recent times have led to increasing interest in naturally occurring lignocellulosic materials as they are abundant and biodegradable. Pearl Millet (PM) stalks are currently discarded in North India and add to agrowaste generation. In this study, raw stalk of PM was characterized for physicochemical properties such as composition, moisture content, water absorbency and thermal behaviour. Morphology and crystallinity were studied using scanning electron microscope and X-ray diffraction respectively. Pure cellulose, extracted from the stalk using an optimised process, was characterised similarly. XRD patterns indicate the presence of cellulose type I structure with crystallinity index of 32% for raw stalk and 55% for the purified material. Water absorbency was 10 g/g for raw and 13 g/g for extracted cellulose. Material was thermally stable up to 200 °C. These findings indicate that PM stalks may be used as an indigenous source of cellulose for the absorbent layer in hygiene products.