In this study, residual oil from oil palm decanter cake (OPDC) was recovered using n-hexane through Soxhlet extraction process. The residual oil recovered was analysed for its physical and chemical properties. The oil content, moisture, Free Fatty Acid (FFA), Peroxide Value (PV), Iodine Value (IV), Deterioration of Bleachability Index (DOBI) and carotene were measured as 15.43±0.45% (dry), 70.96±0.14%, 6.42±0.11%, 4.37±0.04 meq/kg, 53.28±0.02 g/100 g, 1.93±0.03 and 833.20±39 ppm respectively. The results showed that its fatty acid composition, carotene and IV were comparable with the Malaysian Palm Oil Board (MPOB) standard for crude palm oil (CPO), whilst the properties of the other value had slightly exceeded due to oxidation during the extraction process.
Palm Oil Fuel Ash (POFA) is a biomass produced from palm oil industries. POFA is known to contain
a high amount of silica and has been proven by XRF spectroscopy, in which the silicon dioxide content
is 72.63%. In this study, silica was synthesised from POFA. To extract the silica, POFA was fused
with alkaline agent (Na2CO3) before mixing with Cethyltrimetyl Ammonium Bromide (CTAB) and
Sulphuric Acid (H2SO4). Sodium silicate solution from the fusion was used as silica precursor replacing
conventionally used silica source, Tetraethoxilane (TEOS). XRD pattern showed that raw POFA
dominantly consists of silica. Meanwhile, FTIR analysis of the synthesised silica exhibited spectra
bands at 3393 cm-1, 1635 cm-1, 1028 cm-1 and 787 cm-1 that corresponded to the functional groups of
Si-O and O-H. Thus, it could be concluded that silica was successfully extracted from POFA by the
alkaline fusion method.