An EU experiment creates bio-lubricant from leftover cooking oil

A European Union (EU)-funded research initiative has developed an optimized and low-waste method for converting waste cooking oil (WCO) into a valuable feedstock for bio-lubricants, offering a more advanced alternative to the conventional decantation and filtration techniques commonly used in industrial recycling.

The project, known as WORLD (Waste Oils Recycle and Development), was coordinated by the Politecnico di Milano and ran from October 2020 to January 2026 under the EU's Marie Skłodowska-Curie Actions program. The initiative received total funding of EUR 460,000 (approximately USD 543,000).

At the heart of the project is a process that regenerates waste cooking oil through controlled water washing under specific temperature and pH conditions. The resulting purified oil can be used as a raw material for bio-lubricants and other value-added products. To optimize the process, researchers employed a Design of Experiments (DOE) approach combined with multivariate statistical analysis, evaluating factors such as temperature, pH, bentonite dosage, and oil-to-water ratio.

According to Andrea Mele of the Politecnico di Milano, the most effective operating conditions involved washing the oil with water at 75°C and a pH of 6. Under these parameters, the process achieved the best balance of oil recovery, productivity, environmental performance, and waste reduction while minimizing carbon emissions.

The study also found that bentonite—a naturally abundant absorbent clay widely used in oil refining—provided little additional benefit when the water-washing process was carried out under optimized conditions. This suggests that the bentonite treatment step can be significantly reduced or potentially eliminated, simplifying operations and lowering material consumption. Any wastewater and solid by-products generated during the process are recovered and directed into separate recycling streams.

Beyond bio-lubricant production, the researchers identified several promising applications for waste cooking oil. These include its use as a medium for capturing volatile organic compounds (VOCs) from contaminated air and its conversion into glycerol and free fatty acids, such as oleic acid, which can be utilized in the production of deep eutectic solvents (DESs). These solvents are increasingly being explored as lower-cost and lower-toxicity alternatives to conventional chemical solvents.

Alberto Mannu, who participated in the project and is now affiliated with the University of Brescia, noted that VOC capture applications have reached the proof-of-concept stage, while other potential uses remain in earlier phases of development.

Looking ahead, Mele said the team aims to develop a technology platform that can be replicated across different regions, production scales, and industrial environments. The researchers also believe the process could be particularly relevant in regions outside Europe where large quantities of waste cooking oil are generated and sustainable recycling solutions are needed. The detailed article is published by https://www.fuelsandlubes.com/ can be accessed from https://www.fuelsandlubes.com/eu-project-turns-waste-cooking-oil-into-bio-lubricant/