A comparative study on performance of KOH and 32%KOH/ZrO 2-7 catalysts for biodiesel via transesterification of waste Adansonia digitata oil

Abstract

Biodiesel was produced from waste Adansonia digitata oil using KOH as homogeneous and 32%KOH/ZrO 2-7 as heterogeneous catalyst. A comparison between the yields and properties of the biodiesel obtained from the two catalysts was done using international standards. Optimum yield of 96.7% was obtained using 32%KOH/ZrO 2-7 as heterogeneous catalyst at 60 °C in 90 min, 6% of 32%KOH/ZrO 2-7 and 14:1 methanol to oil ratio while optimum yield of 95.1% was obtained using KOH at 60 °C in 60 min at catalyst concentration of 1% and 8:1 methanol to oil ratio. 32%KOH/ZrO 2-7 was characterized using Hammet indicator, XRD and SEM. The XRD and SEM images indicate that the catalyst was granulated and porous with particle size ranging from 0.01 to 0.04μm. The sustainability of 32%KOH/ZrO 2-7 upon recycling and reusing for five times suggests that the catalyst is a suitable candidate for producing biodiesel from Adansonia digitata waste oil. The properties of the biodiesel were comparable to international standards.

Keywords

• Transesterification
• Biodiesel
• Fatty acid methyl ester
• Heterogeneous catalyst
• Homogeneous catalyst