Optimum biodiesel production from waste vegetable oil using functionalized cockle shell and watermelon peels as catalyst

Abstract

The components of bio-waste are particularly abundant in essential minerals like calcium and potassium, which are essential for the manufacture of high-performance biocatalysts for biodiesel synthesis. This research evaluated the prospect of bio-waste heterogeneous catalyst of fused cockle shells and watermelon peels to transesterify waste vegetable oil.

At 900°C and 500℃, the waste feedstocks were dried, calcined, and carbonized, respectively. In order to evaluate the compositional, morphological, structural, and thermal features of both the precursor material as well as the catalyst, they were both characterized. The Box-Behnken design was employed to generate 29 experimental runs to investigate the impact of operational variables notably reaction time, catalyst loading, temperature, and methanol-to-oil molar ratio. The existence of acidic oxides (nickel and silicon) as well as basic oxides (potassium and calcium) demonstrated that the synthesized catalyst was bi-functional.

The catalyst's surface area (105.35 m²/g) and pore volume (0.60 cm³/g) obtained from the BET analysis contributed to a 91.77% biodiesel yield at 63.34 °C reaction temperature, 149.41 min reaction time, 1.05wt% catalyst loading, and a 14.45:1 methanol to oil ratio. The physicochemical parameters of the biodiesel produced were measured and determined to be acceptable in accordance with the European National (EN) and American Society for Testing of Materials (ASTM) quality standards, demonstrating the product's suitability for use as fuel.