Optimization of sequential alkaline–acid fractionation of pine sawdust for a biorefinery

The aim of this work was to apply an alkaline–acid sequence for the fractionation of slash pine sawdust, to obtain a solid lignocellulosic material (which can be subsequently delignified to obtain pure cellulose), and separate liquid fractions containing extractives and hemicelluloses. Processes were optimized using a central composite design of two variables for the alkaline extraction stage (NaOH concentration and temperature), and another of three variables for the acid treatment (H2SO4 concentration, time and temperature). Yield and contents of extractives, lignin, carbohydrates and degradation products, all by NREL Standards were determined. Maximum removal of extractives in the alkaline stage (90.7%) was reached using 5% NaOH (oven dry basis, od) at 90 °C for 1 h, and maximum hemicelluloses extraction in the acid stage (57%) was obtained using 7.5 g/L H2SO4 at 150 °C for 30 min The alkaline–acid sequence has shown to be effective for the sequential extraction of resin and hemicelluloses from slash pine sawdust, making possible its use for the production of high value products. Fil: Stoffel, Romina Bettiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina Fil: Felissia, Fernando Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina Fil: Curvelo da Silva, Antonio Aprigio. Universidade de Sao Paulo; Brasil Fil: Gassa, Liliana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina Fil: Area, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentina