Valorisation of invasive plant species in the production of polyelectrolytes.
The purpose of this work was the valorization of wood/wastes of two invasive tree species, namely Acacia dealbata and Ailanthus altissima, in the production of polyelectrolytes as high value-added products for a range of applications. Kraft cooking of wood chips followed by the introduction of quaternary ammonium groups into the cellulose backbone using a typical sodium periodate oxidation/Girard's reagent T cationization was performed. Water-soluble polyelectrolytes were obtained with a cationic group content of 3.0-3.6 mmol/g which were characterized, and, as a proof of concept, evaluated as flocculants in the treatment of an industrial effluent from olive oil mill, a harsh and difficult to treat effluent. Under optimized conditions of pH (4.5-7) and flocculant dosage (50-100 mg/L), an effluent turbidity removal of up to 65% was achieved. The proposed approach enabled to obtain, for the first-time, valuable polyelectrolytes from very low value woods, with potential interest for application as flocculants in effluent treatment. Additionally, the experiments also proved that there is no need to completely remove lignin from wood before cationization, mild deconstruction procedures allowing to produce water-soluble polyelectrolytes and achieve a good performance in the flocculation process.