BIODIESEL PRODUCTION FROM WASTE COOKING OIL USED FOR HEAVY METAL EXTRACTION AND CHEMICAL QUALITY CHARACTERIZATION OF BIOFUELS

Abstract

ABSTRACT Alternative fuels such as biodiesel have been investigated and have the potential to grow rapidly due to their lower environmental impacts. Several processes are used to remove heavy metals especially chromium from industrial effluent. This project demonstrates for the first time the multiple re-use of refined palm oil firstly for cooking, then as a diluent in the extraction of Cr(VI) from electroplating effluent and lastly as biodiesel after transesterification of spent diluent. An economic way to remove free fatty acid (FFAs) using alpha cyclodextrine and carbonized biomass was also investigated. Based on previous studies, the waste cooking oil was proven to be a suitable replacement of kerosene to extract Cr (VI) from synthetic electroplating effluents at an efficiency of 94-98% with Alamine 336 (Hasan, 2011). In this study, the overall efficiency of extraction process was between 93-98%. In order to re-use the Alamine 336 for a new cycle of extraction, Alamine 336 was stripped from Cr (IV) using 0.1 M Na2CO3 with an efficiency of 89-92%. Centrifugation process was carried out to avoid the loss of waste cooking oil (WCO) diluent from the oil to the aqueous phase during the extraction and stripping process. The spent WCO diluent was then used for biodiesel production and the chemical properties of this biodiesel were investigated. For kinematic viscosity, the result obtained for waste cooking oil and oily Alamine 336 were 9.77x10-4 mm2/s and 7.19x10-4 mm2/s respectively. Besides, waste cooking oil and oily Alamine 336 were investigated to have 1.68 % and 11.42 % of water and sediment content respectively. While sulphated ash for waste cooking oil was 0.4 % and 2.6 % for oily Alamine 336. It is possible that the recycle cooking oil that has been used in metal extraction may contain chromium content that may affect the quality of biodiesel and cause environmental pollution.