Deactivation of PdNi catalyst on nanoporous carbon support derived from cattail leaves in synthesis of partially hydrogenated biodiesel(h-fame)

Abstract

Nowadays, biodiesel is an alternative energy that is widely used to replace fossil fuels because of its high heat value comparable to fossil fuels. Biodiesel was easily oxidized within air. It is commonly blended with diesel fuel to have the proper properties and increase shelf life. Partial hydrogenation is one of the processes used to enhance the properties of biodiesel. In this research, bimetallic PdNi on nanoporous carbon (NPC) support derived from cattail leaves was successfully synthesized via hydrothermal carbonization and chemical activation. The prepared nanoporous carbon has a high surface area of ​​2002 m2g-1, obtained by activation process with 4 M of potassium hydroxide at 900 °C. Optimal condition and deactivation of PdNi/NPC in partial hydrogenation at various temperatures (80, 100, 120 and 140 ° C), pressure (3, 4 and 5 bar) and stirring rate (150, 200 and 300 rpm) were investigated. It was found that an operation at 100 °C, 4 bar and a stirring speed of 150 rpm offered the biodiesel with increased oxidation stability to 18.34 h. Furthermore, the results indicated that the deactivation of catalyst occurred from two main factors: poisoning of sulfur molecules in biodiesel feedstock and carbon residue covering on the surface of the catalyst. The addition of nickel in the bimetallic form led to increased cis-C18:1 selectivity and decreased the catalyst deactivation in the partial hydrogenation process.