Nowadays, agricultural wastes represent an alternative source of renewable raw materials. Different processes could be applied to these alternative materials to separate its components and obtain chemical products with high added value such as bioethanol, organic acids, monomers and biopolymers. The main objective of this work is to study the extraction of hemicelluloses from corn stalks by acid or basic catalyst [H2SO4, HNO3, HCL, CH3COOH, CF3COOH, Ca(OH)2, NaOH] adjusting solution pH to 4 or 8 with these reagents. The raw material was characterized and fractionated with autoclave hydrolysis processes (121°C, 1:20 solid/liquid ratio, 60 min, pH = 4 or 8). Monomeric sugars concentration, TDS, MO, MI, density and final pH of the hydrolysate were determined. Hemicelluloses were precipitated and analyzed by different techniques (FTIR, TGA and GPC). The highest yield of hemicelluloses extraction was achieved by sulphuric acid (0.98 g/L total sugar content) and the less effective reagent was Ca(OH)2 (0.52 g/L total sugar content).
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机译：如今，农业废弃物已成为可再生原材料的替代来源。可以对这些替代材料应用不同的工艺，以分离其成分并获得具有高附加值的化学产品，例如生物乙醇，有机酸，单体和生物聚合物。这项工作的主要目的是研究用酸或碱性催化剂[H2SO4，HNO3，HCl，CH3COOH，CF3COOH，Ca（OH）2，NaOH]从玉米秸秆中提取半纤维素的方法，用这些试剂将溶液的pH调节至4或8 。对原料进行表征，并通过高压釜水解工艺（121°C，固液比为1：20，60分钟，pH = 4或8）进行分馏。测定了水解产物的单体糖浓度，TDS，MO，MI，密度和最终pH。通过不同的技术（FTIR，TGA和GPC）沉淀和分析半纤维素。用硫酸（总糖含量为0.98 g / L）可获得最高的半纤维素提取率，而效果较差的试剂是Ca（OH）2（总糖含量为0.52 g / L）。
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