A multi-modal and process intensification study of a sequential acid-solvent protocol for valorizing waste lubricant oil into high-quality base stock

  • Abubakar Habib Idris Department of Chemistry, National Open University of Nigeria, University Village, Plot 91, Cadastral Zone, Nnamdi Azikiwe Expressway, Jabi, Abuja, Nigeria
  • Dedah John Department of Chemistry, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Muhammad Mukhtar Department of Science Laboratory Technology, Binyaminu Usman Polytechnic, Hadejia, Jigawa State, Nigeria
  • Aishatu Habib Idris Department of Microbiology, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Jamila Ibrahim Shekaru Department of Chemistry, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Omolade Ojo Department of Science Laboratory Technology, Federal College of Education (Tech.), Gombe, Nigeria
  • Yasser Sabo Takko Sa’adu Zungur University, Bauchi, Nigeria
  • Muhammed Ibrahim Warji Department of Science Laboratory Technology, Federal Polytechnic Kaltungo, Nigeria
  • Abdullahi Aliyu Department of Microbiology, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Abbas Muhammad Sani Department of Chemistry, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Aishatu Khalidah Haladu Department of Chemistry, Abubakar Tafawa Balewa University, Bauchi, Nigeria
  • Usman Mustapha Yero Federal Ministry of Education, Nigeria
  • Hassan Juliet Zuleah Department of Science Laboratory Technology, Auchi Polytechnic, Nigeria
DOI: https://doi.org/10.34198/ejcs.13126.03.027042
Keywords: waste lubricant oil (WLO), process intensification, microwave-assisted extraction, reaction kinetics and mechanism, life cycle assessment (LCA)

Abstract

The transition to a circular economy for hydrocarbons demands advanced recycling paradigms for waste lubricant oil (WLO). This study presents a holistic, multi-modal investigation of an intensified sequential process integrating acid pre-treatment with methanol extraction for WLO valorization. To complement conventional analysis, High-Resolution Mass Spectrometry was employed to deconvolute the molecular-level transformation, identifying and quantifying the removal of more than 500 distinct contaminant species. The mechanism of acid treatment was elucidated through in-situ FTIR spectroscopy, which quantified second-order reaction kinetics (k = 2.3 × 10⁻³ L mol⁻¹ s⁻¹) for metal-carbonate dissociation. Density Functional Theory calculations provided a quantum-mechanical rationale for solvent efficacy, revealing strong, spontaneous binding between methanol and key oxidation products (e.g., ΔGbind= -5.2 kcal/mol with stearic acid). Microwave-assisted extraction enhanced process efficiency, reducing processing time by 95.8 % and increasing yield by 8 %. The reclaimed oil exceeded key API Group I specifications, with a kinematic viscosity of 16.49 cSt at 100°C, a flash point of 240°C and a total acid number of 0.05 mg KOH/g. A comparative Life Cycle Assessment demonstrated a 65% reduction in global warming potential compared to virgin base oil production. This work provides a validated framework for sustainable WLO valorization by coupling atomistic-level mechanistic insights with a validated, intensified process.

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References

Al-Ghouti, M. A., & Al-Degs, Y. S. (2011). Remediation of used engine oil contaminated soil using combined extraction and adsorption processes. Environmental Pollution, 159, 2689–2698. https://doi.org/10.1016/j.envpol.2011.05.034

Al-Zahrani, S. M., & Al-Fariss, T. F. (2017). A general review on the recycling of used lubricating oils. Journal of King Saud University – Engineering Sciences, 29(1), 231–239. https://doi.org/10.1016/j.jksues.2015.10.001

Bamiro, O. A., & Osibanjo, O. (2004). Pilot study of used oils in Nigeria. Report for the Secretariat of the Basel Convention.

El-Fadel, M., & Khoury, R. (2001). Strategies for vehicle waste-oil management: A case study. Resources, Conservation and Recycling, 33, 75–91. https://doi.org/10.1016/S0921-3449(01)00070-8

Emam, E. A., & Shoaib, A. M. (2012). Re-refining of used lube oil, II—By solvent/clay and acid/clay-percolation processes. ARPN Journal of Science and Technology, 2, 1034–1041.

Falah, B. H., & Hussien, A. W. (2011). Regeneration of base-oil from waste-oil under different conditions and variables. African Journal of Biotechnology, 10, 1150–1153. https://doi.org/10.5897/AJB10.1860

Hamad, A., Al-Zubaidy, E., & Fayed, M. E. (2005). Used lubricating oil recycling using a combination of acid/clay and a modified solvent extraction process. Energy & Fuels, 19, 455–462. https://doi.org/10.1021/ef049866v

International Energy Agency. (2022). World energy outlook 2022. IEA.

Leonelli, C., & Mason, T. J. (2010). Microwave and ultrasonic processing: Now a realistic option for industry. Chemical Engineering and Processing, 49, 885–900. https://doi.org/10.1016/j.cep.2010.05.006

Lopes, J. A., Menezes, J. C., & Westerhuis, B. (2006). The use of FTIR spectroscopy combined with multivariate analysis for the detection of used vegetable oil adulteration in fresh olive oil. Journal of the American Oil Chemists’ Society, 83, 593–599. https://doi.org/10.1007/s11746-006-1245-4

Machado, I., Pinto, S., & Guedes, P. (2021). Used lubricating oil management: A scientific review of the environmental implications and recycling technologies. Science of the Total Environment, 789, 147985. https://doi.org/10.1016/j.scitotenv.2021.147985

Mang, T., & Dresel, W. (Eds.). (2017). Lubricants and lubrication (3rd ed.). Wiley-VCH. https://doi.org/10.1002/9783527645565

Mettler Toledo. (2020). Reaction monitoring and FTIR kinetics (Application Note).

Mortier, R. M., Fox, M. F., & Orszulik, S. T. (Eds.). (2010). Chemistry and technology of lubricants (3rd ed.). Springer. https://doi.org/10.1007/978-1-4020-8662-5

Nwachukwu, M. A., Alinnor, J., & Feng, H. (2012). Review and assessment of mechanic village potentials for small scale used engine oil recycling business. African Journal of Environmental Science and Technology, 6, 464–475. https://doi.org/10.5897/AJEST12.138

Ogunbayo, A. O., & Akinola, A. A. (2018). Environmental impact of spent engine oil on soil properties and growth of maize (Zea mays L.) in Ibadan, Nigeria. Environmental Monitoring and Assessment, 190, 608. https://doi.org/10.1007/s10661-018-6983-x

Oliveira, L. M., Silva, M. L. C. P., & Rodrigues, M. L. K. (2013). Used lubricating oil re-refining by solvent extraction: A review. Journal of Environmental Chemical Engineering, 1, 213–220. https://doi.org/10.1016/j.jece.2013.04.012

Osman, D. I., & Attia, S. K. (2018). A review of re-refining technologies for used lubricating oils. Egyptian Journal of Petroleum, 27, 1325–1333. https://doi.org/10.1016/j.ejpe.2018.07.002

Reis, M. A. R., & Jeronimo, M. S. (1988). Used lubricating oil re-refining by extraction-flocculation. A scientific basis for the design of an efficient and environmentally acceptable process. Industrial & Engineering Chemistry Research, 27, 1222–1228. https://doi.org/10.1021/ie00079a023

Rincón, J., Cañizares, P., & García, M. T. (2007). Regeneration of used lubricant oil by polar solvent extraction. Industrial & Engineering Chemistry Research, 46, 266–272. https://doi.org/10.1021/ie0605945

Santos, J. C. O., Santos, I. M. G., Souza, A. G., Sobrinho, E. V., & Fernandes, V. J. (2020). Thermal and physicochemical characterization of lubricating oils: A review. Journal of Thermal Analysis and Calorimetry, 140, 2211–2226. https://doi.org/10.1007/s10973-019-08964-5

Speight, J. G. (2014). The chemistry and technology of petroleum (5th ed.). CRC Press. https://doi.org/10.1201/b16559

Srinivasan, P. T., & Viruthagiri, T. (2015). Recycling of used lubricating oil by solvent extraction. Indian Journal of Science and Technology, 8, 1–6. https://doi.org/10.17485/ijst/2015/v8i15/54115

Udonne, J. D., & Bakare, A. A. (2019). A comparative study of recycling of used lubrication oils using distillation, acid and activated charcoal with clay methods. Journal of Petroleum Engineering, 2019, 8912717. https://doi.org/10.1155/2019/8912717

Van de Voort, F. R., Sedman, J., & Yaylayan, V. (2004). FTIR spectroscopy: The next generation of oil analysis. Tribology & Lubrication Technology, 60, 28–35.

Zubaidy, E. A., & Abouelnasr, D. M. (2010). Fuel recovery from waste oily sludge using solvent extraction. Process Safety and Environmental Protection, 88, 318–326. https://doi.org/10.1016/j.psep.2010.04.001

Published
2025-12-10
How to Cite
Idris, A. H., John, D., Mukhtar , M., Idris, A. H., Shekaru, J. I., Ojo, O., Takko, Y. S., Warji, M. I., Aliyu, A., Sani, A. M., Haladu, A. K., Yero, U. M., & Zuleah, H. J. (2025). A multi-modal and process intensification study of a sequential acid-solvent protocol for valorizing waste lubricant oil into high-quality base stock. Earthline Journal of Chemical Sciences, 13(1), 27-42. https://doi.org/10.34198/ejcs.13126.03.027042
Issue
Vol 13 No 1 (2026): (February Issue - in Progress)
Section
Articles


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