High-Yield Alpha-Cellulose from Oil Palm Empty Fruit Bunches by Optimizing Thermochemical Delignification Processes for Use as Microcrystalline Cellulose

Abstract

Oil palm empty fruit bunches (OPEFB) are lignocellulosic materials that are a by-product of the palm oil industry, which have less use and utilization is still limited. OPEFB’s high cellulose content could potentially develop into various bioproducts, especially biomaterials. The thermochemical delignification process can obtain high-yieldalpha-cellulose. The cellulose extraction process can be done by combining the bleaching process under acidic conditions and alkaline delignification to obtain high-purity cellulose. The bleaching conditions vary in the concentration of NaClO2, the length of bleaching, the temperature, and the number of stages. The research obtains high α-cellulose by optimizing bleaching conditions under acidic conditions in cellulose’s OPEFB extraction with variability on NaClO2 concentration and bleaching time using response surface methodology (RSM). The bleaching process was implemented at an early stage with a concentration of 3% NaClO2 and a bleaching time of 2 hours as a center point with a bleaching cycle of twice at pH 4–4.5 using acetic acid. Bleached fibers were delignified using 10% NaOH for 2 hours at room temperature. The RSM analysis resulted in optimum bleaching conditions at a concentration of 3.22% NaClO2 for 1 hour, yielding OPEFB’s cellulose of 82.96% ± 2.53, hemicellulose of 9.27% ± 2.28, and lignin of 1.68% ± 0.58. The validation and verification process in the bleaching conditions obtained cellulose of 84.87% and α-cellulose of 88.51%, with a crystallinity index of 70.55% and crystallite size of 2.35 nm. Scanning electron microscopy on surface cellulose morphology at optimum bleaching helped remove hemicellulose impurities, lignin, and inorganic materials and a more intensive opening of cellulose fibrils. The bleaching process optimization point was verified to improve the delignification performance and potentially produce high yield α-cellulose content for microcrystalline cellulose use.

Effect of Leaf Powdering Technique on the Characteristics of Date Palm-Derived Cellulose

“…The cellulose extraction process involves multiple steps, including delignification, alkaline treatment, and bleaching. NaClO is employed in the bleaching step, which primarily targets residual lignin and other impurities to enhance cellulose purity . Maintaining optimal conditions including temperature, pH, and concentration of NaClO during the NaClO bleaching process is essential for minimizing the generation of unwanted byproducts such as dioxins.…”

“…NaClO is employed in the bleaching step, which primarily targets residual lignin and other impurities to enhance cellulose purity. 64 Maintaining optimal conditions including temperature, pH, and concentration of NaClO during the NaClO bleaching process is essential for minimizing the generation of unwanted byproducts such as dioxins. By carefully controlling these parameters, the bleaching reaction can be carried out efficiently, ensuring high-quality cellulose extraction, while reducing the environmental impact associated with the process.…”

Understanding polyamidoamine epichlorohydrin (PAAE) retention in paper

“…The hydrolysis of these bonds, especially ester-based bonds, during the kraft pulping process or during the bleaching process will make available carboxylic groups on hemicellulose and cellulose on lower kappa and bleached pulps. In such cases, the electrostatic attraction between the anionic carboxylated group of the fiber and the cationic azetidinium group of PAAE would be favored (Chen 2014;Nishimura et al 2018;Tarasov et al 2018;Terrett and Dupree 2019;Cui et al 2022;Susi et al 2023).…”