Pineapple crown delignification using low-cost ionic liquid based on ethanolamine and organic acids.

Pineapple fibre was treated with protic ionic liquids (PILs) and the effects on the structure, composition, and properties of the fibres were evaluated. Treatment with PILs efficiently exposed the fibre surface, as confirmed by scanning electron microscopy. The chemical composition analysis revealed reductions in the lignin and hemicellulose contents in the treated fibres, promoting exposure of cellulose. The results correlated with the crystallinity index, which was greater in the treated fibres compared with that in the untreated fibres. The generated residue from the treatment of fibres with PIL (1%, v/v) showed lower levels of toxic compounds, demonstrating the advantages of this treatment over conventional biomass treatments.