Mn2+ Assisted Catalytic Hydrolysis of Water Hyacinth Cellulose under Mild Conditions

Cellulose isolated from water hyacinth was hydrolyzed using organic and biomimetic acid catalysts under controlled thermal and solvent conditions. Piperazine dihydrogen sulfate showed higher hydrolysis efficiency compared to glutamic and maleic acids. The presence of Mn2+ further enhanced depolymerization, increasing cellulose conversion from 35.35% to 41.40% in aqueous medium and up to 49.48% in a water-acetonitrile system at 85°C. Despite increased depolymerization, glucose yield remained below 16%, with a maximum value of 15.26% obtained in the Mn2+-assisted aqueous system. The discrepancy between overall hydrolysis and glucose formation indicates the presence of soluble intermediates or secondary transformation during heating. The reaction pathway is consistent with proton-assisted glycosidic bond cleavage enhanced by metal coordination. Greenness assessment using the AGREE metric yielded an overall score of 0.56, indicating moderate environmental performance primarily limited by batch configuration and energy demand.