Sustainable utilization of water hyacinth for cellulose beads: Effect of pretreatment time on morphology, porosity, and swelling capacity

The growing demand for sustainable solutions to combat environmental pollution and resource depletion has accelerated research into the utilization of invasive biomass such as water hyacinth (Eichhornia crassipes). This study investigates the potential of water hyacinth as a renewable raw material for the production of cellulose beads, offering an eco-friendly alternative for applications in water purification, packaging, and biomedical fields. Cellulose was extracted through a two-step chemical process involving NaOH delignification and NaClO₂ bleaching. The influence of varying acid-ethanol pretreatment times (30, 60, 90, 120, 150, and 180 min) on cellulose dissolution and bead formation was evaluated. Cellulose beads were synthesized using a NaOH-urea solvent system and coagulated in HNO₃ solution. The resulting beads (0.03–0.05 g, 3.6–4.3 mm) were characterized using optical microscopy, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and swelling capacity analysis. FTIR analysis confirmed the retention of cellulose-specific functional groups across all pretreatment durations, with consistent O–H, C–H, and C–O–C bands observed, indicating successful delignification and chemical stability of the regenerated cellulose. Among all variations, beads pretreated for 90 min exhibited the most favorable characteristics, including smooth, spherical morphology and the highest swelling capacity (18.38 %), indicating superior adsorption potential. These findings highlight the feasibility of utilizing water hyacinth-derived cellulose for sustainable bead production and support its application in environmental and biomedical sectors