Synergistic deinking effect of neutral sodium sulfite with fungal hemicellulase enzyme for improved recycling of waste papers.

The study examined the beneficial effects of the synergistic deinking and delignification process on the quality of recycled pulp. By utilizing a mixture of neutral sodium sulfite, sodium carbonate, and fungal hemicellulase enzyme, the research demonstrated that the paper achieved enhancements in brightness, whiteness, tensile and burst indices, while also exhibiting reduced yellowness and ERIC in comparison to paper derived from chemically deinked pulp. The high-resolution ESCA analysis demonstrated a reduction in lignin surface coverage, and enhancement in the O/C atomic ratios. FTIR spectra indicated notable alterations in the structure of fibers and the functional groups of deinked pulp fibers. XRD spectra confirmed a higher cellulose crystallinity index and FESEM micrographs illustrated a rougher surface with the emergence of new fibrils. Additionally, UV analysis of the pulp effluents indicated significant lignin absorbance, while post-bleaching with H 2 O 2 further enhanced the reactivity of the pulp and the overall quality of the paper. [ABSTRACT FROM AUTHOR]