The effect of different pre-treatments to improve delignification of eucalypt stumps in a biorefinery context

Abstract E. globulus stumps are recently considered as feedstock for pulp industries. Pre-treatments may improve delignification, increase pulp quality and promote other cellulosic applications. Five environmentally friendly pre-treatments were studied: liquid hot water (LHW), oxalic acid (OA), alkaline peroxide (AHP), sodium xylenesulfonate (SXS) and iron (III) chloride (FeCl 3 ). The pre-treatments presented different yields: 94.7% (LHW), 92.7% (OA), 79.0% (AHP), 74.8% (SXS) and 78.9% (FeCl3). The chemical composition and FTIR analysis, including infrared structural ratios, of the pre-treated solids showed changes in cell wall structure. OA, SXS and FeCl 3 pre-treatments were more selective for hemicelluloses extraction. Mass loss and pulp yield occurred considerably with AHP (21.0%; 53.9%), SXS (25.2%; 46.0%) and FeCl 3 (21.1%; 30.7%) . The pre-treated material was delignified by the kraft process, bleached using an ECF sequence (D 0 E 1 D 1 E 2 D 2 ), and the pulp properties were evaluated. LHW improved the pulp physical properties while OA, AHP and SXS showed potential for production of dissolving pulps.