Abstract
Diesel engines are used extensively in heavy-duty transportation due to their high thermal efficiency and energy density, but they also contribute to environmental pollution. Water-in-diesel emulsions have emerged as an alternative method for decreasing NOx and emissions, but there are still obstacles to assuring engine performance and stability. Surfactants are used to stabilise the emulsion by decreasing the interfacial tension between the fuel and water. Studies on water-in-diesel emulsions published literature suggest that chemical surfactants have been used in the production of emulsified fuels. In addition, research have shown that biosurfactants are less harmful to the environment than chemical surfactants. However, only limited study has been conducted on the use of biosurfactants in emulsified fuel. Consequently, it is important to investigate the possible use of biosurfactants in applications using emulsified fuels. This research studies the categorization of surfactants and biosurfactants and emulsion methods for the development of emulsified fuel. This research also aids in the selection of the most suitable surfactant and biosurfactant for applications, particularly in the context of water-in-diesel emulsions and diesel-in-water emulsions, with the goal of developing an environmentally friendly, stable emulsified fuel that can reduce the emission effect and protect the environment.