Isolation and characterization of cellulose from date palm waste using rejected brine solution

This study introduces a new and waste-to-waste treatment approach to isolate cellulose from lignocellulosic biomass. Rejected brine solution from desalination plant was utilized to remove noncellulosic components from the date palm leaves. Free chlorine available in rejected brine solution was responsible for the separation of cellulose from lignocellulosic structure. The proximate analysis revealed that the isolated cellulose exhibited a substantial volatile content of 83.70%, rendering it well-suited to produce bio-oil. Various other analytical techniques including FTIR, chemical composition analysis, proximate and ultimate analysis, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) were employed to confirm the cellulose enrichment. Cellulose fibers with needle−shaped morphology were obtained. Cellulose fibers were having high thermal stability (T_onset = 250 ^○C) and crystallinity index (64.75%) compared to raw waste (T_onset = 226 ^○C; 53.58%). In addition, the activation energy (E_a) of both date palm leaves and isolated cellulose were investigated using the Coats−Redfern model−fitting method. The activation energy values obtained were 79.39 kJ/mol for date palm leaves and 103.27 kJ/mol for isolated cellulose. This research shows a completely new process for pretreatment of lignocellulosic wastes to isolate cellulose. This approach helps reduce the waste management cost associated with date palm waste and desalination plants to promote the concept of circular economy. Moreover, enriched cellulose derived from waste palm leaves using desalination brine presents sustainable options for eco−friendly packaging, textiles, biodegradable composites, and enhanced bio-oil production applications.