• J. C. Nnaji
  • E. G. Onyezeka
Keywords: Waste frying oil, feedstock, characterization, esterification


The main objective of the study was to characterize and esterify ten waste frying oil (WFO) samples collected from fried food vendors and analyse their suitability as feedstock for biodiesel production. The parameters of the WFOs analyzed included; colour, odour, pH, specific gravity, kinematic viscosity (Oswald viscometer), moisture content (oven drying method), iodine value, acid value and saponification value. Esterification was carried out to lower the free fatty acid (FFA) contents of the waste frying oils. Mean values for specific gravity varied from 0.892±0.022 to 0.905±0.075 g/cm3. The mean kinematic viscosity of the WFOs ranged from 43.120 ±1.530 to 97.530 ±6.360 mm2/s. The mean acid value obtained varied from 2.730 ±0.404 to 16.956 ±3.806 mg/g while the mean free fatty acid concentration in the WFO ranged from 1.95 ±0.17 to 12.09 ±2.11 mg/g. Results indicated that WFOs used for frying fish may not be good feedstocks for biodiesel production since they contained the highest levels of FFA. Both refined and unrefined oils were used for frying in the sampling area. The foodstuffs fried in the oils included Akara (bean cake), yam, potato, plantain and fish. Duration of use of the oils ranged from 5 days to 3 weeks. After, esterification, only the free fatty acid contents of 4 samples were reduced below 0.5% by esterification while others ranged between 0.70% and 2.59%. Optimum conditions for the esterification were methanol: concentrated sulphuric acid ratio of 42:1; reaction temperature of 60oC; reaction time of 30 min with 5 min application of heat.


Abdullah, N., Hassan, S. H. and Mohd, M. R. (2013). Biodiesel Production Based on Waste Cooking Oil (WCO). International Journal of Materials Science and Engineering, 1: 1-7

Ahmia, A. C., Danane, F., Bessah, R. and Boumesbah, I. (2014). Raw Material for Biodiesel Production. Volarization of Used Edible Oil as an Alternative Feedstock for Biodiesel. Energies, 1(1): 3 – 18.

Antolin, G., Tinaut, F. V., Briceno, Y., Castano, V., Perez, C. and Ramirez, A. I. (2002). Optimization of Biodiesel Production by Sunflower Oil Transesterification. Bioresource Technology, 83(2): 111 – 124.

AOCS. (1997). Free Fatty Acid - Official Method Ca 5a-40. American Oil Chemists Society, Champaign, Illinois

Arjun, B., Chhetri, K.,Watts, C. and Rafigul, M. I. (2008). Waste Cooking Oil As an Alternative Feedstock for Biodiesel. Energies, 1(1): 3 – 18.

Azhari, M. S., Leni, M., Ishak, I. and Sya F. M. (2013). Waste Frying Oil-Based Biodiesel. Process and Fuel Properties. Smart Grid and Renewable Energy, 4(3): 281 – 286.

Balat, M. and Balat, H. (2010). Progress in Biodiesel Processing. Applied Energy, 87(5): 1815 – 1835.

Chhetri, A. B., Watts, K. C. and Islam, M. R. (2008). Waste Cooking Oil as an Alternate Feedstock for Biodiesel Production. Energies, 1(1): 3-18

Costa Neto, P., Rossi, L., Zagonel, G. and Ramos, L. (2000). The Utilization of Used Frying Oil for the Production of Biodiesel. Quimica Nova, 23: 531 – 537.

Crabbe, E., Nolasco-Hipolito, C., Kobayashi, G., Sonomoto, K. and Ishizaki, A. (2001). Biodiesel Production from Crude Palm oil and evaluation of Butanol extraction and Fuel Properties. Process Biochemistry, 37: 65–71

Falade, A. O., Oboh, G. and Okoh, A. I. (2017). Potential Health Implications of the Consumption of Thermally-Oxidized Cooking Oils – a Review. Polish Journal Food and Nutrition Sciences 67(2): 95–105

Fasogbon, O. (2019). How Unhealthy Vegetable Oils are Killing Nigerians. Available at:

Filho, P. A. and Badr, O. (2004). Biomass Resources for Energy in North-Eastern Brazil. Applied Energy, 77(1): 51 – 67.

Hossain A.B.M.S. and Boyce A.N. (2009). Biodiesel production from waste sunflower cooking oil as an environmental recycling process and renewable energy. Bulgarian Journal of Agricultural Science 15: 312-317.

Hossain, A. B. M. S., Boyce, A. N. Salleh, A. and Chandran, S. (2010). Impacts of Alcohol type, ratio and stirring Time on the Biodiesel Production from Waste Canola Oil. African Journal of Agricultural Research, 5(14): 1851 – 1859.

Issariyakul, T., Kulkarni, M.G., Dalai, A.K. and Bakhshi, N.N. (2007). Production of biodiesel from waste fryer grease using mixed methanol/ethanol system. Fuel Process Technology 88: 429-436.

Kannahi, M. and Arulmozhi, R. (2013). Production of Biodiesel from Edible and non- Edible Oils Using Rhizopus oryzae and Aspergillus niger. Asian Journal of Plant Science and Research, 3(5): 60 – 65.

Leong, X. F., Ng, C. Y., Jaarin, K. and Mustafa, M. R. (2015). Effects of Repeated Heating of Cooking Oils on Antioxidant Content and Endothelial Function. Austin Journal of Pharmacology and Therapeutics 3(2): 1-7

Mahgoulb, H. A., Salih, N. A., Mohammad, A. A. (2015). International Journal of Multidisciplinary and Current Research, 3: 1-6

Martini, N. and Schell, S. (1997). Plant Oil as Fuels. Present State of Future Development. In Proceedings of the 1997 Springer Symposium Berlin, Germany, pp 16 – 18.

McKendry, P. (2002).Energy Production from Biomass (part 1). Overview of Biomass. Bioresource Technology, 83(1): 37 – 46.

NAFDAC. (2019). Fats and Oils Regulations 2019. National Agency for Food and Drug Administration and Control, Abuja.

Omolara, O. O. and Dosumu, O. O. (2009). Preliminary Studies on the Effect of Processing Methods on the Quality of three commonly consumed Marine Fishes in Nigeria. Biokemistri 21(1): 1–7

Prafulla, P. D., Veera, G. G., Harvind, R. K., Tapaswy, M. and Shuguang, D. (2012). Biodiesel production from waste cooking oil using sulfuric acid and microwave irradiation processes. Journal of Environmental Protection 3: 107-113.

Tan, Y. H., Abdullah, M. O., Hipolito, C. N., Taufiq-Yap, Y. H. (2015). Waste Ostrich and Chicken-Eggshells as Heterogeneous Base Catalyst for Biodiesel Production from Used Cooking Oil: Catalyst Characterization and Biodiesel Yield Performance. Applied Energy, 2: 1-13

Wang, Y., Ou, S., Liu, P. and Zhang, Z. (2007). Preparation of biodiesel from waste cooking oil via two-step catalyzed process. Energy Conversion and Management 48: 184–188.

World Energy Council. (2013). World Energy Resources, Survey. Available at:

Zhu, H., Wu, Z., Chen, Y., Zhang, P., Duan, S., Liu, X.. (2006). Preparation of Biodiesel catalysed by Solid Super Base of Calcium Oxide and its Refining Process. Chinese Journal of Catalysis, 27(5): 391-396.

How to Cite

Most read articles by the same author(s)