Hot Water Extraction of Hemicelluloses from Aspen Wood Chips of Different Sizes
نویسندگان
چکیده
Hot water extraction of hemicelluloses from aspen wood chips of different sizes and wood meal was performed, and the extracted hemicelluloses were characterized. With decreasing wood chip size, the total sugars and total polyand oligosaccharides extracted with hot water increased. The dissolution of hemicelluloses was mainly limited by diffusion in the fiber wall and mass transfer from fiber to fiber during hot water extraction of the wood chips. The extraction yield of high molecular weight hemicelluloses was less than that of low molecular weight hemicelluloses, and the reduction of wood chip size benefited the extraction of high-molecular weight hemicelluloses. Compared to the wood chips, the high molecular weight hemicelluloses extracted from wood meal had a higher extraction yield and an increased average molecular weight.
منابع مشابه
REMOVAL OF HEMICELLULOSES BY NaOH PRE-EXTRACTION FROM ASPEN CHIPS PRIOR TO MECHANICAL PULPING
Hemicelluloses can be removed from wood chips prior to mechanical pulping, which would offer new feedstocks for the production of chemicals and fuels. The aim of this study was to evaluate pre-extraction to maximize pre-extraction yield, while minimizing negative impacts on wood chips. The effects of three independent process variables (NaOH charge, pre-extraction temperature, and time) on thre...
متن کاملHot-water Extraction of Ground Spruce Wood of Different Particle Size
Hot-water extraction of hemicelluloses, especially galactoglucomannans, from fractions of ground spruce wood with different particle sizes was studied at 170°C with extraction times up to 60 min. Extraction of spruce sapwood, heartwood, and thermomechanical pulp (TMP) was also compared at 160 to 180°C. Static batch extractions were carried out in an accelerated solvent extractor (ASE). The extr...
متن کاملDegradation and Redeposition of the Chemical Components of Aspen Wood during Hot Water Extraction
Hot water extraction (HWE) prior to pulping of wood is a promising method in constructing a platform for traditional pulping or for biorefinery processing. In this study, HWE of aspen wood at a maximum reaction temperature (Treaction) between 140 and 180 oC was investigated to obtain an optimal extraction condition for wood-derived products. The effect of extraction temperature and reaction tim...
متن کاملThomas Elder * and Carl Houtman Time - domain NMR study of the drying of hemicellulose extracted aspen ( Populus tremuloides
The effect of hot water on aspen chips has been evaluated using time-domain low-field nuclear magnetic resonance (NMR) spectroscopy. At moisture contents above fiber saturation point, treated chips exhibit relaxation times of free water longer than for the control. This is consistent with the removal of hemicelluloses given the hydrophilicity of these polysaccharides. The rate of decrease in fr...
متن کاملSeparation of polymeric galactoglucomannans from hot-water extract of spruce wood.
Two methods for separation of polymeric galactoglucomannans (GGMs) from a hot-water extract of spruce wood, i.e., membrane filtration and precipitation in ethanol-water, were compared. Filtration through a series of membranes with different pore sizes separated GGMs of different molar masses, from polymers to oligomers. Only polysaccharides were precipitated in ethanol-water. With the optimal w...
متن کامل