Optimization of biodiesel synthesis from microalgal (Spirulina platensis) oil by using a novel heterogeneous catalyst, β-strontium silicate (β-Sr2SiO4).

• Heterogeneous catalyst β-strontium silicate has been used for the first time for biodiesel production. • Catalyst have been performed up to six cycles with 76.34% FAME conversion. • Transesterification process was optimized by response surface methodology (RSM). • A FAME conversion of 97.88% was obtained from spirulina sp. microalgal oil. The β-Strontium silicate (β -Sr 2 SiO 4) was synthesized by physicochemical methods and was used as a heterogeneous catalyst in biodiesel production from microalgal oil (- S pirulina platensis ) by transesterification process. The physical and chemical properties of the catalyst were analysed using TGA, XRD, ATR-FTIR, SEM-EDX, and surface area analyser. XRD and FTIR analyses confirmed the formation of β-Sr 2 SiO 4 which was able to perform transeterification reaction. Several reaction parameter such as catalyst wt %, molar ratio (methanol :oil) and time have been optimized for transesterification reaction. The optimization of reaction parameters was accomplished by response surface methodology based on Box-Behnken design. Reusability study of catalyst was accomplished up to six run with 76.34% fatty acid methyl ester (FAME) conversion. A 97.88% maximum FAME conversion was observed at 65 °C, 600 rpm, 2.5 wt% catalyst, 1:12 methanol to oil molar ratio and 104 min reaction time. The biodiesel properties conform to ASTM standards. [ABSTRACT FROM AUTHOR]