Wood waste valorization: Ethanol based organosolv as a promising recycling process

Wood waste is a valuable material that could constitute an abundant and inexpensive source to produce new materials and energy recovery. In Europe, about 46 % of wood waste is recycled to particleboard and fiberboard, while the other fraction is incinerated. However, a considerable quantity of wood waste has the potentiality to be transformed into value-added products due to its compositional quality. In this work, wood waste collected at a mechanical treatment (MT) plant underwent organosolv treatment to produce a cellulose pulp suitable for manufacturing containerboard. Wood waste was microwave heated at 160 °C for 15 min using an acidified ethanol–water solution (2 % w/w H2SO4 and 0.8 w/w ethanol concentration), producing pulp with an average cellulose content of 76 % where 93 % of initial cellulose was retained. Thanks to a one-pot approach, ethanol was totally recovered, 62 % of initial lignin was precipitated, and 20 g/l of hemicellulose-derived sugars solution was obtained. Finally, three wood waste samples collected in different periods of the years yielded comparable outcomes, suggesting a good reproducibility of the organosolv process. This study paves the way for an industrial symbiosis between recycling centers and paper mills located in the same territory, increasing the sustainability and worth of the wood waste recycling process.