A Zanthoxylum bungeanum seed oil-based carbon solid acid catalyst for the production of biodiesel

Abstract

Zanthoxylum bungeanum seed oil (ZSO) cannot be widely consumed because it contains high free fatty acids with an acid value of 73.75 mg KOH per g. Herein, a solid acid catalyst was prepared from ZSO via a carbonization–sulfonation method using concentrated sulfuric acid. The prepared catalyst was characterized by FT-IR, SEM, XPS, XRD, N₂ physisorption, and Boehm titration methods. The prepared solid acid was employed as a catalyst to investigate its performance during the simultaneous esterification and transesterification of ZSO in a one-pot process to produce biodiesel. The optimum reaction parameters for obtaining biodiesel in >95% yield using the abovementioned reaction were as follows: 30 : 1 methanol-to-oil molar ratio, a catalyst loading of 8.0 wt%, a reaction temperature of 140 °C, and reaction time of 4.0 h.