Physical chemical characterization of alkali pretreatment for oil palm empty fruit bunch

摘要

Pretreatment process on lignocellulosic biomass of oil palm empty fruit bunch (OPEFB) is an important stage in the process of converting lignocellulosic biomass route into bioethanol because its determines the success of the overall process. The purpose of this research was to conduct characterization OPEFB's fiber resulted from alkali fiber explosion (ALFEX) and low tempereture alkali (LTA) processes, such as composition of lignocellulosic components, functional group of bonding structure, surface morphology structure, crystallinity, and swelling test. The experiment variations were conducted on sodium hidroxide concentrations of 0, 4, 8, 12, and 15% weight. Based on the results of this research, it was concluded that the ALFEX pretreatment more effective to remove the lignin of OPEFB than the LTA process. The highest decreasing of lignin content in the process ALFEX and LTA were 30,37% and 5,30% that occurred in the sodium hydroxide concentration of 12% and 15%, respectively. The FTIR analysis of OPEFB from ALFEX pretreatment results showed changing in the absorption band of infrared radiation at wave number 1370 cm~(-1), 940 cm~(-1), and 730 cm~(-1). The ALFEX and LTA pretreatments could reduce cellulose crystallinity of OPEFB from 58% to 29%. The ALFEX pretreatment was better to open the complex structure of OPEFB lignocellulose than the LTA process. It was shown in the results of SEM photograph that the OPEFB fibers of ALFEX pretreated became smooth, soft and appeared to swell like a sponge and break down from its bundled structure. The swelling test results indicated that the highest's water absorption value of EFB fibers's ALFEX pretreated occurred in 12% sodium hydroxide concentration which absorbed water until 11 times from the initial fibers weight. While the highest's water absorption value of EFB fiber's LTA pretreated occurred in 15% sodium hydroxide concentration which absorbed water only 3 times from the weight of initial fibers.