Upgrading catalytic properties of green synthesized TiO2 for green fuel production from apricot seeds oil

Abstract

The ongoing energy crisis and global warming issues have pushed the research community to search for sustainable energy supplies such as biodiesel (methyl esters). In this regard, inedible oils which are not consumed by humans could be potential sources for methyl esters production. Herein, the methyl esters were produced by trans-esterifying the apricot seeds oil (ASO) employing series of green synthesized (mediated by banana peel extract) TiO2 based NiO-TiO2 heterogeneous nano-catalysts with varying loadings of NiO (5, 10 and 15 by wt%). The as-prepared catalysts were characterized using advanced techniques like FT-IR, XRD, SEM and FE-SEM. These studies established the successful impregnation of NiO with TiO2 NPs. The efficiency of NiO-TiO2 with 10 wt% of NiO loading calcined at 500 °C was superior due to the highest biodiesel yield compared to other nano-catalysts. The parametric study of transesterification reaction to yield methyl esters adapting this catalyst revealed the maximum yield (93.4 %) with MeOH: oil and catalyst loading of 20:1 and 2 wt% correspondingly in 1 h at 55 °C. GC–MS analysis was executed for investigating and confirming the composition of obtained methyl esters at optimized conditions. Furthermore, the heterogeneous catalyst was reusable for five cycles for transesterification of ASO. The kinetic investigations showed that transesterification of ASO was compatible with pseudo-first order model. In addition, fuel characteristics such as calorific and acid value were measured by using titrations and bomb calorimeter respectively and compared with ASTM6751 and EN14214 standards.