In recent years, the tribology field has expanded with the advent of nanolubrication. Nanolubricants are the name given to the dispersion of nanoparticles in a base oil, and has attracted researchers due to its potential application. In addition to being used in the tribology field, nanoparticles are also used for medical, space, and composites purposes. The addition of nanoparticles in base oils is promising because it enhances specific tribological characteristics including wear-resistance and friction, and the most important reason is that the majority of them are environmentally friendly. This paper reviews the tribological effect of various nanoparticles as lubricant additives. Parameters of nanoparticles that affect tribological performance, the technique to enhance stability, and lubrication mechanism that is currently believed to function will be delineated in detail. Moreover, this review facilitates an understanding of the role of various nanoparticles, which helps in developing and designing suitable nanolubricants for various applications.

This study investigated the tribological behaviour of Pongamia oil (PO) and 15W–40 mineral engine oil (MO) with and without the addition of graphene nanoplatelets (GNPs). The friction and wear characteristics were evaluated in four-ball anti-wear tests according to the ASTM D4172 standard. The morphology of worn surfaces and the lubrication mechanism of GNPs were investigated via SEM and EDS. This study also focuses on the tribological effect of GNP concentration at various concentrations. The addition of 0.05 wt % GNPs in PO and MO exhibits the lowest friction and wear with 17.5% and 12.24% friction reduction, respectively, and 11.96% and 5.14% wear reduction, respectively. Through SEM and EDS surface analysis, the surface enhancement on the worn surface by the polishing effect of GNPs was confirmed. The deposition of GNPs on the friction surface and the formation of a protective film prevent the interacting surfaces from rubbing, resulting in friction and wear reduction.

It has been widely accepted worldwide, that the greenhouse effect is by far the most challenging threat in the new century. Renewable energy has been adopted to prevent excessive greenhouse effects, and to enhance sustainable development. Malaysia has a large amount of biomass residue, which provides the country with the much needed support the foreseeable future. This investigation aims to analyze potentials biomass gases from major biomass residues in Malaysia. The potential biomass gasses can be obtained using biomass conversion technologies, including biological and thermo-chemical technologies. The thermo-chemical conversion technology includes four major biomass conversion technologies such as gasification, combustion, pyrolysis, and liquefaction. Biomass wastes can be attained through solid biomass technologies to obtain syngas which includes carbon monoxide, carbon dioxide, oxygen, hydrogen, and nitrogen. The formation of tar occurs during the main of biomass conversion reaction such as gasification and pyrolysis. The formation of tar hinders equipment or infrastructure from catalytic aspects, which will be applied to prevent the formation of tar. The emission, combustion, and produced gas reactions were investigated. It will help to contribute the potential challenges and strategies, due to sustainable biomass, to harness resources management systems in Malaysia to reduce the problem of biomass residues and waste.

Lubricants are commonly utilized in industry to minimize friction and wear for tools and components, and additives play indispensable roles in lubricants to attain overall enhanced tribological properties. Because of environmental concerns, the introduction of nanoparticles is regarded as a promising lubricant additive capable of replacing conventional additives and improving lubricant tribological properties. This study investigated the tribological behaviour of 5W30 PAO+ester fully synthetic oil (SO) with and without the addition of graphene nanoplatelets. Besides, this study also focuses on the tribological effect of graphene's concentration (0.01, 0.02, 0.05, 0.1 and 0.2 wt%). The experiments were conducted using a four-ball tester according to ASTM D4172 and surface analysis was done on the worn surfaces using scanning electron microscopy and energy-dispersive x-ray spectroscopy. The results show that the presence of graphene significantly improves the tribological properties. SO enriched 0.05 wt% graphene exhibits the lowest coefficient of friction and wear scar diameter, and the friction and wear were reduced by 33.78% and 34.42%, respectively. The protective film formed on the worn surface is responsible for friction and wear reduction. In addition, the worn surface becomes smoother after being lubricated by nanolubricants, which can be observed through the SEM analysis. EDX analysis revealed the presence of element carbon on the worn surface, implying that nanoparticles had deposited on the worn surface.