Synthesis of a Highly Efficient Mesoporous Green Catalyst from Waste Avocado Peels for Biodiesel Production from Used Cooking–Baobab Hybrid Oil

Abstract

Valorization of waste biomass materials for fuels and other energy products has become one of the effective ways of escalating and improving the bioeconomy. The development of a novel biomass solid catalyst obtained from waste avocado peels and its potentials in transesterification of a bi-hybrid oil of used cooking–baobab oil (UC-BO) was investigated in this study. The catalyst was produced by calcining the burnt char of the dried avocado peels. The produced calcined avocado peels catalyst (CAP) was further characterized using analytical equipment, such as FT-IR, XRD, SEM, EDX, and TGA, to ascertain its catalytic properties. The results revealed that CAP contains some vital elements, such as Mg, P, Cl, Ca, Si, Na, and a high percentage of K content, present in form of oxides, carbonates, chlorides, and mixed metal compounds. The catalyst displayed effective catalytic potential in converting the UC-BO to biodiesel with 100% yield under an optimized condition of 51 min reaction time (RT), 14.5:1 of methanol to oil ratio (MTOR), and 2.73 wt% of catalyst loading (CL) at a constant temperature of 60 °C. The CAP exhibited excellent recyclability potential, achieving 92.85% biodiesel yield after five successive reaction cycles without notable catalytic activity reduction. The fuel properties investigated were all established within the biodiesel quality specifications of EN 14241 and ASTM D6751, demonstrating that it is a practical substitute for petroleum fuel.

Keywords

• avocado peels
• biodiesel
• green heterogeneous catalyst
• optimization
• transesterification