Recovery of lignin and phenolics via one-pot pretreatment of oil palm empty fruit bunch fiber and palm oil mill effluent

Abstract

This is a pioneer research carried out to investigate the novel use of palm oil mill effluent (POME) as an extraction solvent of lignin and phenolics from oil palm empty fruit bunch fiber (OPEFBF). In the present study, lignin and phenolics were removed from OPEFBF using different solvents, namely POME, sodium hydroxide (NaOH), aqueous ammonia (NH3), POME containing 5% w/w NaOH (NaOH-POME), and POME containing 5% w/w NH3 (NH3-POME) at different temperatures and times. Results obtained suggest that NaOH-POME was the best solvent to produce the highest yield of lignin (24.2±0.36%) and phenolics (2.4±0.1 g L−1). Chemical oxygen demand (COD) of solvent was increased drastically after treatment but reduced substantially after lignin precipitation. The delignified liquor was a rich source of aromatic aldehydes and acids such as hydroxybenzoic acid, syringaldehyde, syringic acid, vanillin, p-coumaric acid, ferulic acid, and trace amounts of hydroxybenzaldehyde and vanillic acid. Utilization of POME as a solvent to extract lignin and phenolics from OPEFBF is recommended as a win-win approach to simultaneously prepare OPEFBF and POME as a feedstock for downstream processes.