Heterogeneous Catalytic Fractionation of Birch-Wood Biomass into a Microcrystalline Cellulose, Xylose and Enterosorbents

摘要

The main components of the birch wood were fractionated into a microcrystalline cellulose, xylose and enterosorbents by an integration of heterogeneous catalytic processes of an acidic hydrolysis and a peroxide delignification of the wood biomass for the first time. The wood hemicelluloses were hydrolyzed to xylose at a temperature of 150 & DEG;C in the presence of the Amberlyst (R) 15 solid acidic catalyst. Then, the lignocellulosic product of the wood hydrolysis was subjected to the peroxide delignification in the formic acid-water medium in the presence of the solid TiO2 catalyst with a formation of the microcrystalline cellulose (MCC) and the organic-soluble lignin. Yields of MCC and the organic-soluble lignin proved to be 64.5 and 11.5 wt % of a mass of the prehydrolyzed wood, respectively, under the determined optimal conditions (100?degrees C, 7.2 wt % of H2O2, 37.8 wt % of HCOOH, LWR 15, and a duration of 4 h). The enterosorbents were prepared by a treatment of the organic-soluble lignin with 0.4% NaHCO3 or hot water. The sorption capacity of these enterosorbents was 97.7 and 236.7 mg/g according to methylene blue and gelatin, respectively. These values were significantly higher than those of the Polifepan commercial enterosorbent (44 and 115 mg/g, respectively). The products of the catalytic fractionation of the birch wood were characterized by physico-chemical (FTIR, XRD, SEM, and GC) and chemical methods.