Effect of microwave assisted sodium hydroxide pretreatment on hemicellulose content of oil palm empty fruit bunch for furfural production

Oil Palm Empty Fruit Bunch (OPEFB) is one of the main types of solid waste which is continuously produced from palm oil mills. OPEFB contains lignocellulose to which the hemicellulose can be converted into furfural, an important precursor material used for producing high value chemicals, by means of a hydrolysis reaction. This process must be preceded by pretreatment in order to disrupt compact lignocellulose structure of OPEFB and to expose hemicellulose for further hydrolysis reaction. In this study, the optimum pretreatment conditions of OPEFB for hemicellulose recovery by microwave assisted alkali method with aqueous sodium hydroxide is evaluated by using response surface methodology (RSM) based on three-level three-factorial Box-Behnken design. OPEFB powder with different size ranging from 30 - 40 mesh was immersed into sodium hydroxide solution at 1 : 10 solid-liquid ratio. Variations of sodium hydroxide concentrations (1; 2; 3%), microwave power (280; 560; 840 Watt), and radiation time (3; 6; 9 minutes) were examined in this study. The quadratic model showed that pretreatment at 593.43-Watt and 1.15 % sodium hydroxide concentration for 5.99 minutes recovered the highest hemicellulose of OPEFB i.e. 23.22%.