INVESTIGADORES
AREA Maria cristina
artículos
Título:
Upgrading Spent Liquors From NSSC Process II: Lignosulphonates and Hemicelluloses Molecular Weights Distributions
Autor/es:
AREA, M.C., FELISSIA, F.E., VENICA, A., VALADE, J.L.
Revista:
CELLULOSE CHEMISTRY AND TECHNOLOGY
Editorial:
Romanian Academy, Publishing House of the Romanian Academy
Referencias:
Año: 2000 vol. 34 p. 525 - 535
ISSN:
0576-9787
Resumen:
Modern trends ask for the use of pulping processes friendlier to the environment. In the case of the NSSC process (Neutral Sulfite Semi-Chemical) there is a need for disposing spent liquors economically and ecologically. A better knowledge of chemical composition and characteristics of solubilized materials, combined with suitable separation techniques is desired. Hybrid poplar (Populus deltoides) was used as raw material. Twenty-nine spent liquors samples were analyzed. Hemicelluloses and lignosulfonates molecular weights were estimated with the objective of to evaluate if they can be separated in several fractions by ultrafiltration. Both substances present two chromatography peaks. Lignosulfonates average molecular weights were about 1030 and 235 for each peak. Average molecular weights for hemicelluloses first peak vary between 8000 and 19600, and the approximate value is 1000 for the second one. Lignosulfonates molecular weight distributions do not change with pulping conditions, while higher molecular weight hemicelluloses dissolve at more severe cooking conditions.