Document Type : Original Article
Authors
1
M.Sc. in Matrial Science Engineering and Metallurgy, Semnan University, Semnan, Iran; Deputy CEO of Ravan Gostaran Tavan Gharb Company
2
B.Sc. in Applied Chemistry, Islamic Azad University, South Tehran Branch, Tehran, Iran; CEO of Ravan Gostaran Tavan Gharb Company
3
M.Sc student in chemical engineering (Thermosynthetics & Catalysis), Sanandaj university, Sanandaj, Iran; Qc of Ravan Gostaran Tavan Gharb Company
Abstract
The development of bio-based lubricant additives represents a promising strategy for reducing the environmental footprint of engine oils while maintaining the physicochemical and tribological performance required in modern internal combustion engines. Conventional lubricant formulations commonly incorporate antioxidants, antiwear agents, friction modifiers, viscosity modifiers, detergents, and dispersants, several of which are derived from nonrenewable resources or raise concerns regarding persistence, toxicity, and end-of-life management. Bio-based alternatives obtained from vegetable oils, agricultural residues, lignocellulosic biomass, natural phenolic compounds, and other renewable feedstocks offer opportunities to improve lubricity, biodegradability, and resource efficiency. This review examines the mechanisms, performance characteristics, and limitations of these additives, emphasizing their potential application in engine oil formulations. The literature is evaluated in relation to four principal domains: tribological performance, oxidative and thermal stability, physicochemical compatibility, and environmental sustainability. Particular attention given to fatty-acid derivatives, natural antioxidants, chemically modified vegetable oils, bio-derived friction modifiers, and multifunctional additives. The methodological framework combines a structured narrative review with qualitative evidence mapping and comparative assessment of reported findings. Four analytical tables summarize additive classes, functional mechanisms, performance considerations, and formulation requirements. Because the identified studies employ heterogeneous materials, concentrations, test conditions, and performance indicators, the available evidence does not support the calculation of a defensible pooled effect size without additional standardized experimental data. Accordingly, forest-plot-style quantitative synthesis distinguished from qualitative evidence mapping. The review indicates that bio-based additives can provide useful lubricity and sustainability advantages, but their suitability for engine oils depends on oxidation resistance, low-temperature behavior, additive compatibility, deposit control, and compliance with engine-specific performance requirements. Future research should prioritize standardized testing, life-cycle assessment, and validation in fully formulated engine oils under representative operating conditions.
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