Ultrasound-assisted conversion of waste frying oil into biodiesel using Al-doped ZnO nanocatalyst: Box-Behnken design-based optimization. (June 2023)

• Record Type: Journal Article
• Authors: Maleki, Basir; Esmaeili, Hossein
• Is Part Of: Renewable energy. Volume 209(2023)
• Page Start: 10
• Page End: 26
• Publication Date: 2023-06
• Subjects: Transesterification -- Biodiesel -- Waste frying oil -- Nanocatalyst -- Diesel engine -- Box- behnken design; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2023.03.119
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: In this research, ZnO and ZnO@Al nanocatalysts were synthesized and utilized to fabricate biodiesel from waste frying oil (WFO). The structural features of these nanocatalysts were evaluated by FTIR, XRD, Raman, SEM, EDX-mapping, BET, and CO2 -TPD analyses. According to the Box-Behnken design, the optimal conditions for biodiesel generation were attained at ultrasonic time of 29.35 min and 28.04 min, catalyst concentration of 2.57% and 2.35%, and methanol/oil ratio of 10.46 and 10.29 for ZnO and Al-doped ZnO, respectively. In optimal conditions, the utmost yield of biodiesel by ZnO and ZnO@Al nanocatalysts was 91.79% and 96.13%, respectively. Also, the stability and recyclability of nanocatalysts displayed that the Al-doped ZnO nanocatalyst has remarkable recyclability compared to ZnO, and after 7 cycles, the yield of biodiesel by Al-doped ZnO decreased by only 12%. According to the kinetic study, the quasi-first order kinetic was in good agreement with the laboratory data, and the kinetic rate constant enhanced with enhancing temperature. The enthalpy changes for biodiesel generation by ZnO and ZnO@Al were 46.98 and 52.01 kJ/mol, respectively, illustrating that the biodiesel generation reaction is endothermic. Furthermore, the influence of adding WFO-derived biodiesel to petrodiesel on the performance of a CI diesel engine was carefully checked.