Unlocking the Power of Waste Cooking Oils for Sustainable Energy Production and Circular Economy: A Review

Main Article Content

Samson Onoriode Okpo
Emozino Donatus Edafiadhe

Abstract

In the pursuit for sustainable energy solutions, biodiesel has come to prominence as an alternative to petroleum-derived diesel. This review delves into cutting-edge developments in production of biodiesel, emphasizing use of waste cooking oils (WCOs) as an environmentally friendly raw material. Incorporating waste cooking oils (WCOs) into the biodiesel production process not only tackles environmental issues associated with improper disposal but also adheres to the principles of a circular economy. This manuscript covers various methods and technologies for converting WCOs into high-quality biodiesel, emphasizing economic viability and environmental benefits. It discusses the potential of WCO-derived biodiesel to meet stringent fuel standards and reduce greenhouse gas emissions. Significant progress has been made in using waste cooking oils to generate sustainable energy, aligning with broader initiatives focused on renewable energy and circular economy principles. In summary, the utilization of waste cooking oils for biodiesel production presents an opportunity to shift away from reliance on fossil fuels, thereby fostering circular economy practices and sustainability goals.

Article Details

How to Cite
[1]
S. O. Okpo and E. D. Edafiadhe, “Unlocking the Power of Waste Cooking Oils for Sustainable Energy Production and Circular Economy: A Review”, AJERD, vol. 7, no. 1, pp. 41–55, Mar. 2024.
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Articles

References

Nalley, S., & LaRose, A. (2021). International energy outlook 2021, US Department of Energy: Washington, DC, USA. 1-21.

ASTM D6751-08- Standard specification for biodiesel fuel (B100) blend stock for distillate fuels, In: Annual Book of ASTM Standards, ASTM International, West Conshohocken, Method D6751-08, 2008a.

Ziolkowska, J. R. (2020). Biofuels technologies: An overview of feedstocks, processes, and technologies, Biofuels for a More Sustainable Future, 1–19. DOI: https://doi.org/10.1016/B978-0-12-815581-3.00001-4

Malode, S. J., Gaddi, S. A. M., Kamble, P. J., Nalwad, A. A., Muddapur, U. M., & Shetti, N. P. (2022). Recent evolutionary trends in the production of biofuels, Materials Science for Energy Technologies, 5, 262-277. DOI: https://doi.org/10.1016/j.mset.2022.04.001

Maliha, A., Abu-Hijleh, B. A review on the current status and post-pandemic prospects of third-generation biofuels, Energy Systems, 14(4), 1185–1216. DOI: https://doi.org/10.1007/s12667-022-00514-7

Powar, R. S., Yadav, A. S., Ramakrishna, C. S., Patel, S., Mohan, M., Sakharwade, S. G., Choubey, M., Ansu, A.K, & Sharma, A. (2022). Algae: A potential feedstock for third generation biofuel, Materials Today: Proceedings, 63, A27-A33. DOI: https://doi.org/10.1016/j.matpr.2022.07.161

Veluru, S., Hamzah, H.T., Tukaram Bai, M, Poiba, V.R. & Mahdi, H.S. (2022). A Review on biodiesel production from various feedstocks by transesterification, IOP Conf. Series: Materials Science and Engineering, 1258(1), 012024. DOI: https://doi.org/10.1088/1757-899X/1258/1/012024

Singh, D., Sharma, D., Soni, S. L., Sharma, S., Kumar Sharma, P. & Jhalani, A. (2019). A review on feedstocks, production processes, and yield for different generations of biodiesel, Fuel, 262, 116553. DOI: https://doi.org/10.1016/j.fuel.2019.116553

Paschalidou, A., Tsatiris, M. & Kitikidou, K. (2016). Energy crops for biofuel production or for food? - SWOT analysis (case study: Greece), Renewable Energy, 93, 636-647. DOI: https://doi.org/10.1016/j.renene.2016.03.040

Adenuga, A. A., Oyekunle, J. A. O. & Idowu, O. O. (2021). Pathway to reduce free fatty acid formation in Calophyllum inophyllum kernel oil: A renewable feedstock for biodiesel production, Journal of Cleaner Production, 316, 128222. DOI: https://doi.org/10.1016/j.jclepro.2021.128222

Athar, M. & Zaidi, S. (2020). A review of the feedstocks, catalysts, and intensification techniques for sustainable biodiesel production, Journal of Environmental Chemical Engineering, 8(6), 104523. DOI: https://doi.org/10.1016/j.jece.2020.104523

Awogbemi, O., Von Kallon, D. V., Aigbodion, V. S. & Panda, S. (2021b). Advances in biotechnological applications of waste cooking oil, Case Studies in Chemical and Environmental Engineering, 4, 100158. DOI: https://doi.org/10.1016/j.cscee.2021.100158

Khan, H. M., Iqbal, T., Yasin, S., Irfan, M., Kazmi, M., Fayaz, H. & Ullah, N. (2021). Production and utilization aspects of waste cooking oil based biodiesel in Pakistan, Alexandria Engineering Journal, 60(6), 5831–5849. DOI: https://doi.org/10.1016/j.aej.2021.04.043

Teixeira, M. R., Nogueira, R. & Nunes, L. M. (2018). Quantitative assessment of the valorisation of used cooking oils in 23 countries, Waste management, 78, 611-620. DOI: https://doi.org/10.1016/j.wasman.2018.06.039

Yusuff, A. S., Adeniyi, O. D., Olutoye, M. A. & Akpan, U. G. (2018). Waste frying oil as a feedstock for biodiesel production, in Petroleum Chemicals-Recent Insight, ed. M. Zoveidavianpoor, IntechOpen, London, UK, 5-24.

Topi, D. (2020). Transforming waste vegetable oils to biodiesel, establishing of a waste oil management system in Albania, SN Applied Sciences, 2, 1-7. DOI: https://doi.org/10.1007/s42452-020-2268-4

Sarno, M., & Iuliano, M. (2019). Biodiesel production from waste cooking oil, Green Processing and Synthesis, 8(1), 828-836. DOI: https://doi.org/10.1515/gps-2019-0053

Casallas, I. D., Carvajal, E., Mahecha, E., Castrillon, C., Gomez, H., Lopez, C. & Malagon-Romero, D. (2018). Pre-treatment of waste cooking oils for biodiesel production, Chemical Engineering Transactions, 65, 385-390.

Saini, R. D. (2017). Conversion of waste cooking oil to biodiesel, International Journal of Petroleum Science and Technology, 11(1), 9-21.

Math, M. C., Kumar, S. P., & Chetty, S. V. (2010). Technologies for biodiesel production from used cooking oil - A review, Energy for Sustainable Development, 14(4), 339-345. DOI: https://doi.org/10.1016/j.esd.2010.08.001

Maddikeri, G. L., Pandit, A. B., & Gogate, P. R. (2012). Intensification approaches for biodiesel synthesis from waste cooking oil: a review, Industrial & Engineering Chemistry Research, 51(45), 14610-14628. DOI: https://doi.org/10.1021/ie301675j

Statista (2023). Global production of vegetable oils from 2000/01 to 2022/23 (in million metric tons), Statista Research Department. https://www.statista.com/statistics/263978/global-vegetable-oil-production-since-2000-2001/. Assessed Online 24/08/2023 at 9.30am

EUBIA - The European Biomass Industry Association (2015). Transformation of used cooking oil into biodiesel: from waste to resource, Technical Report of European Biomass Industry Association. 1-8.

Mannu, A., Ferro, M., Pietro, M. E. D., & Mele, A. (2019). Innovative applications of waste cooking oil as raw material, Science Progress, 102(2), 153-160. DOI: https://doi.org/10.1177/0036850419854252

Adepoju, T. F., & Olawale, O. (2014). Acid-catalyzed esterification of waste cooking oil with high FFA for biodiesel production, Chemical and process engineering research, 21, 80-85.

Foo, W. H., Chia, W. Y., Tang, D. Y. Y., Koay, S. S. N., Lim, S. S., & Chew, K. W. (2021). The conundrum of waste cooking oil: Transforming hazard into energy, Journal of hazardous materials, 417(2021), 126129. DOI: https://doi.org/10.1016/j.jhazmat.2021.126129

Aderibigbe, F. A., Saka, H. B., Mustapha, S. I., Amosa, M. K., Shiru, S., Tijani, I. A., Babatunde, E.O., & Bello, B. T. (2023). Waste Cooking Oil Conversion to Biodiesel Using Solid Bifunctional Catalysts, ChemBioEng Reviews, 10(3), 293-310. DOI: https://doi.org/10.1002/cben.202200036

Salihu, A., Mahmood, A. A., Gimba, S. B., Nzerem, P., & Okafor, I. (2021). Production of biodiesel from waste cooking oil by transesterification process using heterogeneous catalyst, Nigerian Journal of Environmental Sciences and Technology (NIJEST) 5(2), 501-510. DOI: https://doi.org/10.36263/nijest.2021.02.0308

Falowo, O. A., Oladipo, B., Taiwo, A. E., Olaiya, A. T., Oyekola, O. O., & Betiku, E. (2022). Green heterogeneous base catalyst from ripe and unripe plantain peels mixture for the transesterification of waste cooking oil, Chemical Engineering Journal Advances, 10, 100293. DOI: https://doi.org/10.1016/j.ceja.2022.100293

Amenaghawon, A. N., Obahiagbon, K., Isesele, V., & Usman, F. (2022). Optimized biodiesel production from waste cooking oil using a functionalized bio-based heterogeneous catalyst, Cleaner Engineering and Technology, 8, 100501. DOI: https://doi.org/10.1016/j.clet.2022.100501

Linganiso, E. C., Tlhaole, B., Magagula, L. P., Dziike, S., Linganiso, L. Z., Motaung, T. E., Moloto, N., & Tetana, Z. N. (2022). Biodiesel production from waste oils: a South African outlook, Sustainability, 14(4), 1983. DOI: https://doi.org/10.3390/su14041983

Osagiede, C. A., & Aisien, F. A. (2024). Biochar-based bi-functional catalyst derived from rubber seed shell and eggshell for biodiesel production from waste cooking oil, Fuel, 358, 130076. DOI: https://doi.org/10.1016/j.fuel.2023.130076

Fernandez, C., Bernal, A., Leon, P., Gelves, O., & Malagon-Romero, D. H. (2022). Optimization of a Route for Collecting Waste Cooking Oil in Bogotá, Chemical Engineering Transactions, 91, 625-630.

Tsai, W. T. (2019). Mandatory recycling of waste cooking oil from residential and commercial sectors in Taiwan, Resources, 8(1), 38. DOI: https://doi.org/10.3390/resources8010038

Van Grinsven, A., Van den Toorn, E., Van der Veen, R., & Kampman, B (2020). Used Cooking Oil (UCO) as a biofuel feedstock in the EU, Publications of CE Delft, 1-65.

De Feo, G., Di Domenico, A., Ferrara, C., Abate, S., & Sesti Osseo, L. (2020). Evolution of waste cooking oil collection in an area with long-standing waste management problems, Sustainability, 12(20), 8578 DOI: https://doi.org/10.3390/su12208578

Febijanto, I., Ulfah, F. & Trihadi, S. E. Y. (2023). A Review on used cooking oil as a sustainable biodiesel feedstock in Indonesia, In IOP Conference Series: Earth and Environmental Science, 1187(1), 012011. DOI: https://doi.org/10.1088/1755-1315/1187/1/012011

Cárdenas, J., Orjuela, A., Sánchez, D. L., Narváez, P. C., Katryniok, B. & Clark, J. (2021). Pre-treatment of used cooking oils for the production of green chemicals: A review, Journal of Cleaner Production, 289, 125129. DOI: https://doi.org/10.1016/j.jclepro.2020.125129

Matusinec, J., Hrabec, D., Šomplák, R., Nevrlý, V., & Redutskiy, Y. (2022). Cooking oils and fat waste collection infrastructure planning: a regional-level outline, Clean Technologies and Environmental Policy, 24(1), 109-123. DOI: https://doi.org/10.1007/s10098-021-02087-y

Loizides, M. I., Loizidou, X. I., Orthodoxou, D. L., & Petsa, D. (2019). Circular bioeconomy in action: collection and recycling of domestic used cooking oil through a social, reverse logistics system, Recycling, 4(2), 16. DOI: https://doi.org/10.3390/recycling4020016

Susilowati, E., Hasan, A., & Syarif, A. (2019). Free fatty acid reduction in a waste cooking oil as a raw material for biodiesel with activated coal ash adsorbent, Journal of Physics: Conference Series, 1167(1), 012035. DOI: https://doi.org/10.1088/1742-6596/1167/1/012035

Biofuels International. (2021).The conversion of used cooking oils into biodiesel, https:// biofuels-news.com/news/the-conversion-of-used-cooking-oils-into-biodiesel/

Danane, F., Bessah, R., Alloune, R., Tebouche, L., Madjene, F., Kheirani, A.Y., & Bouabibsa, R. (2022). Experimental optimization of Waste Cooking Oil ethanolysis for biodiesel production using Response Surface Methodology (RSM), Science and Technology for Energy Transition, 77(14), 1-10. DOI: https://doi.org/10.2516/stet/2022014

Kedir, W. M., Wondimu, K. T., & Weldegrum, G. S. (2023). Optimization and characterization of biodiesel from waste cooking oil using modified CaO catalyst derived from snail shell, Heliyon, 9(5), 1-13. DOI: https://doi.org/10.1016/j.heliyon.2023.e16475

Tsoutsos, T. D., Tournaki, S., Paraíba, O., & Kaminaris, S. D. (2016). The Used Cooking Oil-to-biodiesel chain in Europe assessment of best practices and environmental performance, Renewable and sustainable energy reviews, 54, 74-83. DOI: https://doi.org/10.1016/j.rser.2015.09.039

Kristiana, T., O’Connell, A., & Baldino, C. (2023). Producing high quality biodiesel from used cooking oil in Indonesia, ICCT working paper, 2023-18, 1-15.

Gurdil, G. A. K., Kabutey, A., Selvi, K. Ç., Hrabe, P., Herak, D., & Frankova, A. (2020). Investigation of heating and freezing pretreatments on mechanical, chemical and spectral properties of bulk sunflower seeds and oil, Processes, 8(4), 411. DOI: https://doi.org/10.3390/pr8040411

Neuman, T. (2014). Use of separators, decanters in biodiesel processing, Biodiesel Magazine. https://biodieselmagazine.com/articles/use-of-separators-decanters-in-biodiesel-processing-17995 [online: assessed 26th December 2023, 1.20pm]

Ju, J., Zheng, Z., Xu, Y., Cao, P., Li, J., Li, Q. & Liu, Y. (2019). Influence of total polar compounds on lipid metabolism, oxidative stress and cytotoxicity in HepG2 cells, Lipids in Health and Disease, 18(1), 1-13. DOI: https://doi.org/10.1186/s12944-019-0980-0

Foo, W. H., Koay, S. S. N., Tang, D. Y. Y., Chia, W. Y., Chew, K. W., & Show, P. L. (2022). Safety control of waste cooking oil: transforming hazard into multifarious products with available pre-treatment processes, Food Materials Research, 2(1), 1-11. DOI: https://doi.org/10.48130/FMR-2022-0001

Mamtani, K., Shahbaz, K., & Farid, M. M. (2021). Glycerolysis of free fatty acids: a review, Renewable and Sustainable Energy Reviews, 137, 110501. DOI: https://doi.org/10.1016/j.rser.2020.110501

Ennetta, R., Soyhan, H. S., Koyunoglu, C., & Demir, V. G. (2022). Current technologies and future trends for biodiesel production: a review, Arabian Journal for Science and Engineering, 47(12), 15133-15151. DOI: https://doi.org/10.1007/s13369-022-07121-9

Salaheldeen, M., Mariod, A. A., Aroua, M. K., Rahman, S. A., Soudagar, M. E. M. & Fattah, I. R. (2021). Current state and perspectives on transesterification of triglycerides for biodiesel production, Catalysts, 11(9), 1121. DOI: https://doi.org/10.3390/catal11091121

Singh, D., Sharma, D., Soni, S. L., Inda, C. S., Sharma, S., Sharma, P. K, & Jhalani, A. (2021). A comprehensive review of biodiesel production from waste cooking oil and its use as fuel in compression ignition engines: 3rd generation cleaner feedstock, Journal of Cleaner Production, 307, 127299. DOI: https://doi.org/10.1016/j.jclepro.2021.127299

Saad, M., Siyo, B., & Alrakkad, H. (2023). Preparation and characterization of biodiesel from waste cooking oils using heterogeneous Catalyst (Cat. TS-7) based on natural zeolite, Heliyon, 9(6), 1-13. DOI: https://doi.org/10.1016/j.heliyon.2023.e15836

Degfie, T. A., Mamo, T. T., & Mekonnen, Y. S. (2019). Optimized Biodiesel Production from Waste Cooking Oil (WCO) using Calcium Oxide (CaO) Nano-catalyst, Scientific Reports, 9(1), 18982. DOI: https://doi.org/10.1038/s41598-019-55403-4

Sakthivel, R., Ramesh, K., Purnachandran, R., & Shameer, P. M. (2018). A review on the properties, performance and emission aspects of the third generation biodiesels, Renewable and Sustainable Energy Reviews, 82, 2970-2992. DOI: https://doi.org/10.1016/j.rser.2017.10.037

EN 14214- Committee for Standardization Automotive fuels—fatty acid methyl esters (FAME) for diesel engines—requirements and test methods, European Committee for Standardization, Brussels; 2003a. Method EN 14214.

Wang, B., Wang, B., Shukla, S. K., & Wang, R. (2023). Enabling catalysts for biodiesel production via transesterification, Catalysts, 13(4), 740. DOI: https://doi.org/10.3390/catal13040740

Mandari, V., & Devarai, S.K. (2022). Biodiesel Production Using Homogeneous, Heterogeneous, and Enzyme Catalysts via Transesterification and Esterification Reactions: a Critical Review, Bioenergy Research, 15, 935–961. DOI: https://doi.org/10.1007/s12155-021-10333-w

Vilas Boas, R.N., & Mendes, M.F. (2022). A review of biodiesel production from non-edible raw materials using the transesterification process with a focus on influence of feedstock composition and free fatty acids, Journal of the Chilean Chemical Society, 67(1), 5433-5444. DOI: https://doi.org/10.4067/S0717-97072022000105433

Pikula, K., Zakharenko, A., Stratidakis, A., Razgonova, M., Nosyrev, A., Mezhuev, Y., Tsatsakis, A. & Golokhvast, K. (2020). The advances and limitations in biodiesel production: feedstocks, oil extraction methods, production, and environmental life cycle assessment, Green Chemistry Letters and Reviews, 13(4), 275-294. DOI: https://doi.org/10.1080/17518253.2020.1829099

Singh, C. S., Kumar, N., & Gautam, R. (2021). Supercritical transesterification route for biodiesel production: Effect of parameters on yield and future perspectives, Environmental Progress & Sustainable Energy, 40(6), e13685. DOI: https://doi.org/10.1002/ep.13685

Neupane, D. (2022). Biofuels from Renewable Sources, a potential option for biodiesel production, Bioengineering, 10(1), 1-29. DOI: https://doi.org/10.3390/bioengineering10010029

Gaurav, A., Ng, F. T., & Rempel, G. L. (2016). A new green process for biodiesel production from waste oils via catalytic distillation using a solid acid catalyst–Modeling, economic and environmental analysis, Green Energy & Environment, 1(1), 62-74. DOI: https://doi.org/10.1016/j.gee.2016.05.003

Goortani, B. M., Gaurav, A., Deshpande, A., Ng, F. T., & Rempel, G. L. (2015). Production of isooctane from isobutene: energy integration and carbon dioxide abatement via catalytic distillation. Industrial & Engineering Chemistry Research, 54(14), 3570-3581. DOI: https://doi.org/10.1021/ie5032056

Pascoal, C. V. P., Oliveira, A. L. L., Figueiredo, D. D., & Assunção, J. C. C. (2020). Optimization and kinetic study of ultrasonic-mediated in situ transesterification for biodiesel production from the almonds of Syagrus cearensis. Renewable Energy, 147, 1815-1824. DOI: https://doi.org/10.1016/j.renene.2019.09.122

Moazeni, F., Chen, Y. C., & Zhang, G. (2019). Enzymatic transesterification for biodiesel production from used cooking oil, a review, Journal of cleaner production, 216, 117-128. DOI: https://doi.org/10.1016/j.jclepro.2019.01.181

Bagal, M.V., Shaju, M., Yadav, A., & Chavan, S. (2020). Review: enzymatic tranesterification of waste, Journal of Emerging Technologies and Innovative Research (JETIR), 7(6), 1132-1142.

Patil, P. D., Reddy, H., Muppaneni, T., & Deng, S. (2017). Biodiesel fuel production from algal lipids using supercritical methyl acetate (glycerin-free) technology, Fuel, 195, 201-207. DOI: https://doi.org/10.1016/j.fuel.2016.12.060

Pal, A., Verma, A., Kachhwaha, S. S., & Maji, S. (2010). Biodiesel production through hydrodynamic cavitation and performance testing, Renewable Energy, 35(3), 619-624. DOI: https://doi.org/10.1016/j.renene.2009.08.027

Andreani, L., & Rocha, J. D. (2012). Use of ionic liquids in biodiesel production: a review, Brazilian Journal of Chemical Engineering, 29(1), 1-13. DOI: https://doi.org/10.1590/S0104-66322012000100001

Cheng, J., Mao, Y., Guo, H., Qian, L., Shao, Y., Yang, W., & Park, J. Y. (2022). Synergistic and efficient catalysis over Brønsted acidic ionic liquid [BSO3HMIm][HSO4]–modified metal–organic framework (IRMOF-3) for microalgal biodiesel production, Fuel, 322, 124217. DOI: https://doi.org/10.1016/j.fuel.2022.124217

Zhang, Q., Hu, Y., Li, S., Zhang, M., Wang, Y., Wang, Z., & Pan, H. (2022). Recent advances in supported acid/base ionic liquids as catalysts for biodiesel production, Frontiers in Chemistry, 10, 999607. DOI: https://doi.org/10.3389/fchem.2022.999607

Gholami, A., Pourfayaz, F., & Maleki, A. (2020). Recent advances of biodiesel production using ionic liquids supported on nanoporous materials as catalysts: a review, Frontiers in Energy Research, 8, 144. DOI: https://doi.org/10.3389/fenrg.2020.00144

Troter, D. Z., Todorović, Z. B., Đokić-Stojanović, D. R., Stamenković, O. S., & Veljković, V. B. (2016). Application of ionic liquids and deep eutectic solvents in biodiesel production: A review, Renewable and Sustainable Energy Reviews, 61, 473-500. DOI: https://doi.org/10.1016/j.rser.2016.04.011

Liu, C. Z., Wang, F., Stiles, A. R., & Guo, C. (2012). Ionic liquids for biofuel production: opportunities and challenges, Applied energy, 92, 406-414. DOI: https://doi.org/10.1016/j.apenergy.2011.11.031

Ramadhan, A.R., Pornwongthong, P., Rattanaporn, K., & Sriariyanun, M. (2015). Review of Ionic Liquid as a Catalyst for Biodiesel Production, Journal of Science and Technology MSU, 34(4), 404-412.

Chintagunta, A.D., Zuccaro, G., Kumar, M., Kumar, S. J., Garlapati, V.K., Postemsky, P.D., Sampath Kumar, N.S., Chandel, A.K., & Simal-Gandara, J. (2021). Biodiesel production from lignocellulosic biomass using oleaginous microbes: prospects for integrated biofuel production, Frontiers in Microbiology, 12, 1-23. DOI: https://doi.org/10.3389/fmicb.2021.658284

Shi, S., Valle‐Rodríguez, J. O., Siewers, V., & Nielsen, J. (2011). Prospects for microbial biodiesel production, Biotechnology journal, 6(3), 277-285. DOI: https://doi.org/10.1002/biot.201000117

Sharma, A., Kodgire, P., & Kachhwaha, S. S. (2019). Biodiesel production from waste cotton-seed cooking oil using microwave-assisted transesterification: Optimization and kinetic modeling, Renewable and Sustainable Energy Reviews, 116, 109394. DOI: https://doi.org/10.1016/j.rser.2019.109394

Nayak, S. N., Bhasin, C. P., & Nayak, M. G. (2019). A review on microwave-assisted transesterification processes using various catalytic and non-catalytic systems, Renewable Energy, 143, 1366-1387. DOI: https://doi.org/10.1016/j.renene.2019.05.056

El Sherbiny, S. A., Refaat, A. A., & El Sheltawy, S. T. (2010). Production of biodiesel using the microwave technique, Journal of Advanced Research, 1(4), 309-314. DOI: https://doi.org/10.1016/j.jare.2010.07.003

Palma, V., Barba, D., Cortese, M., Martino, M., Renda, S. & Meloni, E. (2020). Microwaves and heterogeneous catalysis: A review on selected catalytic processes, Catalysts, 10(2), 246. DOI: https://doi.org/10.3390/catal10020246

Martinez-Guerra, E., & Gude, V. G. (2015). Continuous and pulse sonication effects on transesterification of used vegetable oil, Energy Conversion and Management, 96, 268-276. DOI: https://doi.org/10.1016/j.enconman.2015.02.073

Riyanto, T., Istadi, I., Buchori, L., Anggoro, D. D., & Dani Nandiyanto, A. B. (2020). Plasma-assisted catalytic cracking as an advanced process for vegetable oils conversion to biofuels: A mini review, Industrial & Engineering Chemistry Research, 59(40), 17632-17652. DOI: https://doi.org/10.1021/acs.iecr.0c03253

Cubas, A. L. V., Machado, M. M., Pinto, C. R. S. C., Moecke, E. H. S., & Dutra, A. R. A. (2016). Biodiesel production using fatty acids from food industry waste using corona discharge plasma technology, Waste management, 47, 149-154. DOI: https://doi.org/10.1016/j.wasman.2015.05.040

Karki, S., Sanjel, N., Poudel, J., Choi, J. H., & Oh, S. C. (2017). Supercritical transesterification of waste vegetable oil: characteristic comparison of ethanol and methanol as solvents, Applied Sciences, 7(6), 632. DOI: https://doi.org/10.3390/app7060632

Kulkarni, M. G., & Dalai, A. K. (2006). Waste cooking oil an economical source for biodiesel: a review, Industrial & engineering chemistry research, 45(9), 2901-2913. DOI: https://doi.org/10.1021/ie0510526

Okoro, O. V., Sun, Z., & Birch, J. (2018). Catalyst-free biodiesel production methods: A comparative technical and environmental evaluation, Sustainability, 10(1), 1-22. DOI: https://doi.org/10.3390/su10010127

Oliveira, P. A., Baesso, R. M., Moraes, G. C., Alvarenga, A. V., & Costa-Félix, R. P. (2018). Ultrasound methods for biodiesel production and analysis, Biofuels-State of Development, 121-148. DOI: https://doi.org/10.5772/intechopen.74303

Oliveira, P. A., Baesso, R. M., Morais, G. C., Alvarenga, A. V., & Costa-Félix, R. P. (2021). Ultrasound-assisted transesterification of soybean oil using low power and high frequency and no external heating source, Ultrasonics Sonochemistry, 78(2021), 1-9. DOI: https://doi.org/10.1016/j.ultsonch.2021.105709

Geissdoerfer, M., Savaget, P., Bocken, N. M., & Hultink, E. J. (2017). The Circular Economy–A new sustainability paradigm? Journal of cleaner production, 143, 757-768. DOI: https://doi.org/10.1016/j.jclepro.2016.12.048

Cho, S., Kim, J., Park, H. C., & Heo, E. (2015). Incentives for waste cooking oil collection in South Korea: a contingent valuation approach, Resources, Conservation and Recycling, 99, 63-71. DOI: https://doi.org/10.1016/j.resconrec.2015.04.003

Alias, N. I., Jayakumar, J. K., & Zain, S. M. (2018). Characterization of waste cooking oil for biodiesel production, Jurnal Kejuruteraan, 1(2), 79-83. DOI: https://doi.org/10.17576/jkukm-2018-si1(2)-10

Ganesan, K., Sukalingam, K., & Xu, B. (2019). Impact of consumption of repeatedly heated cooking oils on the incidence of various cancers- A critical review, Critical Reviews in Food Science and Nutrition, 59(3), 488-505. DOI: https://doi.org/10.1080/10408398.2017.1379470

Lopes, M., Miranda, S. M., & Belo, I. (2020). Microbial valorization of waste cooking oils for valuable compounds production–a review, Critical Reviews in Environmental Science and Technology, 50(24), 2583-2616. DOI: https://doi.org/10.1080/10643389.2019.1704602

United Nations General Assembly. (2015). Transforming our world: the 2030 agenda for sustainable development (A/RES/70/1). Retrieved from https://sustainabledevelopment.un.org/post2015/transformingourworld

Gebremariam, S. N., & Marchetti, J. M. (2018). Economics of biodiesel production, Energy Conversion and 660 Management, 168, 74-84. DOI: https://doi.org/10.1016/j.enconman.2018.05.002

Karmee, S. K., Patria, R. D., & Lin, C. S. K. (2015). Techno-economic evaluation of biodiesel production from waste cooking oil—a case study of Hong Kong, International journal of molecular sciences, 16(3), 4362-4371. DOI: https://doi.org/10.3390/ijms16034362

Keera, S. T., El Sabagh, S. M., & Taman, A. R. (2011). Transesterification of vegetable oil to biodiesel fuel using alkaline catalyst, Fuel, 90(1), 42-47. DOI: https://doi.org/10.1016/j.fuel.2010.07.046

Avinash, A., & Murugesan, A. (2017). Economic analysis of biodiesel production from waste cooking oil, Energy Sources, Part B: Economics, Planning, and Policy, 12(10), 890-894. DOI: https://doi.org/10.1080/15567249.2017.1319438

Mohammadshirazi, A., Akram, A., Rafiee, S., & Kalhor, E. B. (2014). Energy and cost analyses of biodiesel production from waste cooking oil. Renewable and sustainable energy reviews, 33(1), 44-49. DOI: https://doi.org/10.1016/j.rser.2014.01.067