Delignification of Wheat Straw by Use of Low-Molecular-Weight Organic Acids

Abstract

A central composite design was used to investigate the influence of the cooking conditions (time, temperature and acid concentration) for wheat straw with organic acid-water mixtures on the properties of the pulp obtained (yield and holocellulose, α-cellulose and lignin contents). A second-order polynomial model, consisting of three independent process variahles, was found to accurately describe the organosolv pulping of wheat straw. The equations derived predict the yield, the holocellulose, α-cellulose and lignin contents of the pulp with multiple-R. R 2 and adjusted-R 2 high values. The process variables must be set low in order to ensure a high yield. Conversely. if high holocellulose and α-cellulose contents and low lignin contents are desired. then a long cooking time (120min), an intermedia temperature (100°C). and a low formic acid concentration (50%) must be used.