Delignification of palm oil empty fruit bunch by hydroxyl radical of microwave radiation under alkaline condition
This work assessed how to remove lignin of palm oil empty fruit bunch (EFB) in environmentally friendly method and less energy. Moreover, delignification was strengthened with additional H2O2 to perform hydroxyl radical by microwave radiation in low NaOH solution of concentration up to 0.8 M, 10%. Setting on microwave, solution was heating up and cause delignification work more effective. Observation at black liquor showed that temperature was influence by microwave radiation duration while NaOH concentration affected total suspended solid increasing. Optimally treated EFB at 0,2 M NaOH with effective lignin removal and holocellulose increasing reached 27% and 26%, respectively. Unfortunately, at higher NaOH concentration, the decomposition penetrated EFB interior, holocellulose and made lignin percentage high again. Therefore, EFB yield got less at higher NaOH concentration because more EFB was sludgy and lost during washing. XRD analysis showed the increasing crystallinity by 2.2%, closer to -cellulose. SEM showed successful impurities removal from EFB surface and Ca, Nb, Si, and Mg detected by EDS.