Optimization of ionic liquid pretreatment of sugar palm fiber for cellulose extraction

Abstract

Various techniques have been utilized to extract cellulose from sugar palm fiber (SPF). This research aims to determine the optimal yield of sugar palm cellulose employing ionic liquid (IL) pretreatment. An IL (1-butyl-3-methylimidazolium chloride ([Bmim][Cl])) and hydrogen peroxide (H2O2) were utilized for the pretreatment and bleaching processes, respectively. The pretreatment process variables were optimized using response surface methodology with a two-level factorial Box-Behnken design (BBD). The effects of different SPF/IL ratios, temperatures, and reaction times regarding cellulose extraction yield were investigated. The optimal conditions for cellulose extraction were found to be a 1:3.7 (w/w) SPF/IL ratio, a reaction time of 40 min, and a temperature of 124 °C. Under these conditions, the amount of cellulose produced was as high as 65.32 %. The extracted samples were subjected to detailed characterization, including chemical composition, functional groups, morphology, crystallinity, and thermal stability. The extracted cellulose showed an average width of 9.61 ± 0.82 μm and the highest crystallinity index of 67.18 % under optimum conditions. This study offers an important understanding of the fractionation of SPF and its efficient conversion to cellulose via [Bmim][Cl] pretreatment, presenting an energy-efficient approach.