Solubilization of Oleic Acid by Myrj 59 Surfactant

Abstract

Palm oil mill effluent (POME) is one of the sources of contamination in effluent that leads to problems such asclogging in drainpipes and sewer lines. POME discharge consists of high content of free fatty acids (FFAs) aswell as high concentration of biochemical oxygen demand (BOD), chemical oxygen demand and suspendedsolids. FFAs in effluent are not favorable due to low water solubility and resistant to biodegradation whenprecipitated from effluent and binds to soil limiting their bioavailability to microorganisms for biodegradation.Nonionic surfactants are favorable as hydrocarbon or oil solubilizer because they can perform at lowtemperatures, has low-foaming characteristics and relatively stable at high temperatures and under harshchemical conditions. Therefore, there is a need for the usage of surfactant that is biodegradable and at the sametime effective at solubilizing FFAs in POME before being released to streams. Thus, FFAs will be keptmobilized and readily available for biodegradation by microorganisms. Oleic acid is a long chain free fatty acidpresents as the major fatty acid component (40-52 %w/w) in palm oil. Oleic acid was selected for solubilizationby biodegradable nonionic surfactant polyoxyethylene (100) stearate with the commercial name Myrj 59. Thesolubilizations were conducted with various concentrations of Myrj 59; below, at and above the critical micelleconcentration (CMC). The amount solubilized was determined by gas chromatography (GC) using flameionization detector (FID) technique. The solubilization process was confirmed by characterizing the solubilizedoil using Fourier Transform infrared (FTIR) to observe changes in chemical bonds. Highest solubilization wasachieved with Myrj 59 solution at above its CMC, solubilizing 516.31 ppm oleic acid. The FTIR spectra showedstrong peak at 2927 cm-1 with high intensity suggesting intermolecular hydrogen bonding between oleic acid andethylene oxide (EO) groups of surfactant.