Lignocellulosic hydrogel from recycled old corrugated container resources using ionic liquid as a green solvent

Lignocellulosic hydrogels are valuable bio-products that have been considered widely in recent investigations. Also, application of low value recycled fibers for high value added products can be of much interest. In this respect, current research has focused on producing hydrogel from recycled old corrugated container (OCC) resources, using 1-butyl-3-methyl-imidazolium chloride ionic liquid (IL) as a green solvent. The results indicated that the IL successfully dissolved OCC fibers, allowing the production of lignocellulosic hydrogel. Considering total water absorption amount as a main criterion for evaluation of hydrogels, the fabricated hydrogel showed promising results (up to 4700% water absorption). X-ray diffraction analysis confirmed obvious reduction in cellulose material crystallinity and crystallite size as a result of the process. Field emission scanning electron microscopy also demonstrated the microstructure of the hydrogel, pore size and shape in the hydrogel, which well supported the laboratory research results. Furthermore, the effect of processing parameters showed that specimens washed with distilled water as the anti-solvent resulted in the highest water absorption. Infrared spectroscopy can be used to suggest the presence of more lignin content in the hydrogel washed with ethanol. Moreover, the best water re-absorption results were observed for the hydrogel washed with distilled water. [Display omitted] •Recycled old corrugated container was successfully dissolved in an ionic liquid as a green solvent.•The fabricated lignocellulosic hydrogel showed promising results (about 4700% water absorption).•The anti-solvent type had significant effect on absorption and re-absorption capacity of the hydrogel.•Successive drying-wetting process of the produced hydrogel decreased the water absorption capacity.