Abstract
•The heterogeneous nanocatalyst used for conversion of waste frying oil to biodiesel.•The biodiesel yield was 94% at a temperature of 60 °C in 90 min using nanocatalyst.•The binary functionality for nanocatalyst as Brønsted acid–base sites was obtained.•FAMEs yield decreased to 86% after four cycles.
The magnetic graphene oxide (GO) supported with heterogeneous ternary mixed metal oxide (MMO) was used as nanocatalyst to enhance the conversion of waste frying oil (WFO) triglycerides to biodiesel via esterification process. In this regard, acidic MGO was modified with three basic metal cations of cerium, zirconium, and strontium oxides to produce heterogeneous MGO@MMO nanocatalyst. The nanocatalyst was characterized by FESEM, TEM, EDX and FTIR. The influence of different parameters such as catalyst material ratio, methanol to oil ratio, contact time, and reaction temperature was studied. Based on the results of effecting parameters, the MGO@MMO nanocatalyst converted WFO to biodiesel with a yield 94%, a reaction time of 90 min, methanol to oil ratio (8:1), and a temperature of 60 °C. Esterification mechanism indicated the MGO@MMO nanocatalyst having both binary Brønsted acid–base sites that increased the conversion yields as compared to MGO and MMO at low temperatures.