Synergistic Effects of CNT–TiO₂ Nanoparticles on Combustion and Performance Characteristics of Waste Plastic Oil–Diesel Blends
J. Environ. Nanotechnol., Volume 15, No 2 (June 2026) pp. 577-587
Abstract
The growing demand for energy and the environmental challenges associated with conventional fossil fuels have driven the search for sustainable and efficient alternative fuels for compression-ignition (CI) engines. In this study, waste plastic oil (WPO), derived from the pyrolysis of discarded plastics, was used as a partial substitute for diesel fuel, along with a hybrid nano-additive consisting of carbon nanotubes (CNTs) and titanium dioxide (TiO₂), to enhance fuel properties. A base fuel blend of diesel and plastic oil in the ratio of 85:15 was prepared, and CNT–TiO₂ nanoparticles were added at concentrations of 10 ppm, 25 ppm, and 50 ppm using magnetic stirring and ultrasonication. The blends were tested in a single-cylinder, four-stroke Kirloskar diesel engine under varying load conditions. Key parameters, including brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), heat release rate (HRR), and cylinder pressure (CP), were analyzed. The results showed a 3.53% increase in BTE and a 6.86% reduction in BSFC for the nano-additive blend compared with the corresponding fuel blend without nano-additives. This enhanced performance was primarily attributed to improved fuel atomization and the enhanced catalytic activity of the nanoparticles, leading to more complete combustion.
Full Text
Reference
Alenezi, R. A., Norkhizan, A. M., Mamat, R., Najafi, G. and Mazlan, M., Investigating the contribution of carbon nanotubes and diesel-biodiesel blends to emission and combustion characteristics of diesel engine, Fuel, 285, 119046(2021).
https://doi.org/10.1016/j.fuel.2020.119046
Awang, M. S. N., Zulkifli, N. W. M., Kalam, A., Abbas, M. M., Ahmad, M. H., Zulkifli, S. A., Abul, K., Muhammad, M. A., Muhammad, H. A., Syahir, A., Zulkifli, Mohd, N. A. M. Y., Wan, M. A. W., Daud, N. S. S. A. and Abdullah, R. F., Carbon nanotube as effective enhancer for performance and emission of diesel engine fueled with waste plastic pyrolytic oil-diesel blend and its combination with titanium oxide nanoparticle, J. Tribologi, 31, 97-114(2021).
http://eprints.um.edu.my/id/eprint/35488
Chinnappan, R., Chandran, M., Elavarasan, R. M. and Nadarajan, P., Influence of hybrid SiO2 and CeO2 nanoparticles on diesel engine emission operated with distilled tire oil blend, Environ. Sci. Pollut. Res., 29(20), 30568-30583(2022).
https://doi.org/10.1007/s11356-021-17883-8
Devaraj, J., Robinson, Y. and Ganapathi, P., Experimental investigation of performance, emission and combustion characteristics of waste plastic pyrolysis oil blended with diethyl ether used as fuel for diesel engine, Energy, 85, 304-309 (2015).
https://doi.org/10.1016/j.energy.2015.03.075
Dhanapal, B., Venkatesan, H. and Moorthy, B., Synergetic effect of hydrogen supplementation with waste cooking oil biodiesel-An assessment of the emission, combustion and performance parameters of a compression ignition engine, Int. J. Hydrogen Energy, 49, 1292-1302 (2024)
https://doi.org/10.1016/j.ijhydene.2023.11.052
EL-Seesy, A. I., Abdel-Rahman, A. K., Bady, M. and Ookawara, S., The influence of multi-walled carbon nanotubes additives into non-edible biodiesel-diesel fuel blend on diesel engine performance and emissions, Energy Procedia, 100, 166-172(2016).
https://doi.org/10.1016/j.egypro.2016.10.160
Gopinath, S. and Devan, P, K., Optimization and Prediction of Reaction Parameters of Plastic Pyrolysis Oil Production Using Taguchi Method, Iran. J. Chem. Chem. Eng., 39(2), 91-103(2020).
https://doi.org/10.30492/IJCCE.2020.33965
Hariram, V. and Mohan, K. G., The effect of injection timing on combustion, performance and emission parameters with AOME blends as a fuel for compression ignition engine, Europ. J. Sci. Res., 79(4), 653 - 665(2019).
Hariram, V., Dhanush, C., Ezhil, M. K., Akilandabharathi, K., Faizaan, A. M., Sivamani, S., Vasudev, K. L. and Premkumar, M. T., Performance assessment of artificial neural network on the prediction of Calophyllum inophyllum biodiesel through two-stage transesterification, Energy Sources, Part A: Rec. Utiliz. Environ. Eff., 43 (9), 1060-1072 (2019)
https://doi.org/10.1080/15567036.2019.1634164
Hariram, V., John, J. G., Seralathan, S. and Micha, P. T., Comparative analysis of combustion, performance and emission phenomenon of a CI engine fuelled with algal and cotton seed biodiesel, Int. J. Amb. Energy, 42(6), 636-647(2021).
https://doi.org/10.1080/01430750.2018.1562977
Hariram, V., Sathishbabu, R., Godwin John, J., Vijayakumar, K., Sangeeth Kumar, E. and Kamakshi Priya, K., Enhanced combustion and emission characteristics of diesel-algae biodiesel-hydrogen blends in a single-cylinder diesel engine, Res. Eng., 26, 104676 (2025)
https://doi.org/10.1016/j.rineng.2025.104676
John, G., Hariram, V., Seralathan, S. and Jaganathan, R. Effect of oxygenate on emission and performance parameters of a CI engine fuelled with blends of diesel-algal biodiesel, Int. J. Renewable Energy Res., 7(4), 2041-2047(2017).
Khan, M. Z. H., Sultana, M., Al-Mamun, M. R. and Hasan, M. R., Pyrolytic waste plastic oil and its diesel blend: fuel characterization, J. Environ. Pub. Hea., 2016(1), 1-6(2016).
https://doi.org/10.1155/2016/7869080
Kumar, S., Prakash, R., Murugan, S. and Singh, R. K., Performance and emission analysis of blends of waste plastic oil obtained by catalytic pyrolysis of waste HDPE with diesel in a CI engine, Energy Convers. Manage., 74, 323-331(2013).
https://doi.org/10.1016/j.enconman.2013.05.028
Kumar, Y. R., Deshmukh, K., Sadasivuni, K. and Pasha, S. K. K., Graphene quantum dot-based materials for sensing, bio-imaging and energy storage applications: a review, RSC Adv., 10, 23861-23898(2020).
https://doi.org/10.1039/D0RA03938A
Mani, M., Nagarajan, G. and Sampath, S., An experimental investigation on a DI diesel engine using waste plastic oil with exhaust gas recirculation, Fuel, 89(8), 1826-1832(2010).
https://doi.org/10.1016/j.fuel.2009.11.009
Najafi, G. and Shadidi, B., The influence of single and multi-carbon nanotubes as additives in diesel-biodiesel fuel blends on diesel engine combustion characteristics, performance, and emissions, Biofuels, 15(2), 177-190(2024).
https://doi.org/10.1080/17597269.2023.2230684
Prabu, A., Exploring the impact of aluminum oxide nanoparticles on waste transformer biodiesel blend under variable injection timing, Sustain. Energy Res., 11(1), 19(2024).
https://doi.org/10.1186/s40807-024-00114-2
Seela, C. R., Carbon nanotubes (MWCNTs) added biodiesel blends: An engine analysis, Rasayan J. Chem., 15(2), 1009-1020(2022).
https://doi.org/10.31788/RJC.2022.1526882
Shekofteh, M., Gundoshmian, T. M., Jahanbakhshi, A. and Heidari-Maleni, A., Performance and emission characteristics of a diesel engine fueled with functionalized multi-wall carbon nanotubes (MWCNTs-OH) and diesel-biodiesel-bioethanol blends, Energy Rep., 6, 1438-1447(2020).
https://doi.org/10.1016/j.egyr.2020.05.025
Venkatesan, H., Sivamani, S., Bhutoria, K. and Vora, H. H., Assessment of waste plastic oil blends on performance, combustion and emission parameters in direct injection compression ignition engine, Int. J. Ambient Energy, 40(2), 170-178(2019).
https://doi.org/10.1080/01430750.2017.1381155
Yusuf, A, A., Veza, I., Ampah, J, D., Afrane, S., Sarikoç, S., Mujtaba, M. A. and Yahuza, I., Experimental study on emissions and particulate characteristics of diesel engine fueled with plastic waste oil, acetone-butanol-ethanol and diesel blends, Process Safe. Environ. Protect., 191 1419-1431 (2024).
https://doi.org/10.1016/j.psep.2024.09.060
Zamzamian, S. A. H., Adl, M. and Tozandehjani, E., Effects of diesel-based nano-hybrid additives on gasoil combustion performance: enhancing calorific value and reducing emissions through optimization of hybrid-nanoparticles, J. Eng. Appl. Sci., 72(1), 1-20(2025).
