Sunday, May 4, 2008
4-15

Lignin recovery from pulping liquors ethanol-water of sugarcane straw: temperature and pH effects

Germán C. Quintana M.1, Gisele Aparecida Amaral Labat2, Adilson Roberto Gonçalves2, and Jorge A. Velásquez J.1. (1) Pulp and Paper Group - Faculty of Chemical Engineering, Universidad Pontificia Bolivariana, Circular 1 No. 70 - 01, Medellín, Colombia, (2) Biotechnology, Escola de Engenharia de Lorena, Universidade de São Paulo, Estrada Municipal do Campinho, s/n, Lorena, 12600-970, Brazil

Currently the organosolv pulping has received most attention. Among these processes the ethanol/water mixture combines high efficiency, low cost and abundance of the ethanol in countries where sugarcane is economically important. Lignin is a by-product of pulping and also low-cost natural macromolecule of plants. Conditions for lignin precipitation on liquors from ethanol-water pulping of sugarcane straw, as temperature effect, acid concentration, type of acid and pH on the final solution were evaluated. Factorial design was held using 24-1 factorial with 4 central points, which were evaluated 4 factors in 12 experiments determining the concentration of residual lignin by reading UV absorption at 280 nm. Absorptivity value found for the lignin from sugar cane straw was 18.293 L * g-1 * cm-1. Temperature and pH are the factors that have a major influence on the amount of precipitated lignin in liquor, showing that thermodynamical factors are most important. The variables have to be fixed in the lower level to reduce the solubility of lignin and increase the content of lignin removed from the liquor (temperature, 5° C; acid concentration, 1N; and pH, 1). The isolated lignin was analyzed by FT-IR spectroscopy; the spectra were recorded from 4000 to 400cm-1. The IR spectra showed GS absorption and a strong band in carbonyls groups that suggests an oxidation process during the ethanol-water pulping. [Acknowledgements: CNPq, Fapesp, Colciencias, ALFA program – LIGNOCARB project]

See more of Poster Session One
See more of General Submissions

See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)