Kinetic and optimization study of ultrasound-assisted biodiesel production from waste coconut scum oil using porous CoFe2O4@sulfonated graphene oxide magnetic nanocatalysts: CI engine approach
Qiongyu Li, Yanshuai Zhao, Tongzhi Liu, Zhaolin Luo, Kunliang Luo, Teng Wang
Abstract
In this study, CoFe 2 O 4 @sulfonated graphene oxide (SGO) heterogeneous nanocatalyst was synthesized and utilized to produce biodiesel from waste coconut scum oil (WCSO). The structural features of CoFe 2 O 4 @SGO nanocatalyst were evaluated by SEM, TEM, EDX , FTIR, XRD , CO 2 /TPD, VSM, and BET analyses. According to these analyses, CoFe 2 O 4 @SGO nanocatalyst has high specific surface area, suitable functional groups, and good reactivity. The highest biodiesel yield using CoFe 2 O 4 @SGO nanocatalyst in optimal conditions (MeOH/WCSO ratio = 12.41, temperature = 64.73 °C, catalyst concentration = 2.24 %, and ultrasonic time = 33.08 min) was 96.87 %. The yield of biodiesel decreased from 96.91 % to 90.17 % after six reuse cycles, which demonstrates the significant stability of CoFe 2 O 4 @SGO nanocatalyst in the transesterification process. After 7 reuse steps, XRD and CO 2 /TPD analyzes revealed that the catalytic activity and crystallinity of the nanocatalyst were almost retained. The kinetic behavior of biodiesel generation showed that the transesterification reaction is endothermic. Enhancing the concentration of biodiesel in the fuel mix had a positive impact on the reduction of CO and UHC emissions, as well as diesel engine parameters such as cylinder pressure, BP, EGT, BSFC, and BTE. Owing to the high biodiesel yield, significant reusability, and positive impacts on the diesel engine, CoFe 2 O 4 @SGO nanocatalyst is recommended for industrial applications.