Adsorption of Water Content in Biodiesel Blends using Potassium Polyacrylate: Impact on Acid Number

Abstract

Abstract Many countries worldwide have implemented the use of biodiesel as a blend with diesel fuel. Since 2023, Indonesia has implemented the use of biodiesel blends up to 35% (B35). As the use of biodiesel as a blend increases, more stringent requirements, particularly regarding water content, have been enforced. In the field of water treatment, hydrogels, specifically potassium polyacrylate (PPA), are utilized to reduce water content by adsorbing water molecules in biodiesel blends. Elevated water content can have detrimental effects on the quality of biodiesel blends. The objective of this study was to evaluate the efficacy of PPA in adsorbing water content in biodiesel blends. The experiment involved a 60-minute water removal process conducted at room temperature and atmospheric pressure. The adsorption results were then analyzed for water content and acid number and compared to predefined specifications. Additionally, an acidity test was conducted to assess the impact of PPA on water adsorption. The research findings demonstrated that PPA was capable of adsorbing approximately 84.47% of water molecules without affecting the acid number of the biodiesel blends. The final measured water content was determined to be 66.03 ppm, and the acid number was found to be 0.14 mg KOH/g, both satisfying the quality requirements specified by the government.