Synthesis of silica (SiO2) from reproducible acid-leached oil palm frond ash (OPFA) via optimized sol–gel method

Abstract

Agricultural waste has been investigated as potential silica precursor in multitude of various studies now a day. For this purpose, oil palm frond (OPF), an abundant oil palm-based biomass produced from oil palm plantation was utilized as the possible silica precursor. This study proposed a reproducible acid leaching treatment of oil palm frond ash (OPFA) and subsequently silica synthesized via optimized sol–gel method. Acid leaching treatment was conducted at optimum concentration, temperature and reaction time. The sol–gel process is the modified version of Stöber method that design to optimized silica production from acid leaching OPFA. The results of acid leaching signify that this process is highly repeatable where acid leached OPFA analysed producing parallel FTIR spectra that indicate each of the batches contain similar functional group that contain silica bonding with either hydroxyl or oxide ion. Meanwhile silica synthesised from the acid leached OPFA via optimized sol–gel method, successfully produced about 67–68% of silica. Both results confirmed that OPF is highly potential as silica precursor and a higher percentage of silica can be synthesized from this agricultural waste when treated accordingly using acid leaching and followed with optimized sol–gel method.