Comparative studies on the pharmacopoeial and flow properties of powdered celluloses extracted from maize cob using different chemical procedures

Abstract

 In this work a comparative study on different methods of extraction of α-cellulose from agricultural residue- maize (Zea mays) cob was carried out. α-Celluloses were extracted from the agricultural residue using various chemical procedures based on:- nitric acid/ sodium hydroxide, sodium hydroxide, organsolvent and ionic liquid (IL) [1-butyl- 3-methylimidazolium chloride ([C₄mim]Cl)]. The chemical composition and flow properties of the extracted α- celluloses were estimated using the known standard methods. The α-celluloses extracted from the agricultural residue using nitric acid/ sodium hydroxide and sodium hydroxide methods, respectively, were relatively free from other lignocellulosic contents (lignin content < 0.70% and hemicelluloses < 1.30%) compared to the organosolvent method (lignin content 1.54-4.03 % and hemicelluloses 4.50-10.05%), and IL method (lignin content 3.45% and hemicelluloses 12.50%). Apart from the α-cellulose obtained with IL, others showed poor flow properties. The results show that the IL method is a promising process for the extraction of cellulose with improved flow characteristics from maize cobs, however, the cellulose method obtained with this method failed pharmacopoeial requirement in terms of purity. Since the ionic liquids can be almost 100% recycled, this might be a low cost, fast, simple and environmentally friendly chemical procedure that can increase significantly the competitiveness of α- cellulose extraction if the purity of the obtained cellulose can be improved upon.