Archachatina marginata Snail-shell as a Feedstock for the Synthesis of Solid Catalysts for Methanolysis of Oil from Palm Kernel in an Optimisation Process

Abstract

The work studied the synthesis of heterogeneous catalysts from Archachatina marginatas nail-shell (AMS) by calcination at 800oC and 900oC for 2 h, to produce snail shell catalyst (SSC) of SSC800 and SSC900 respectively. The catalysts were subsequently used for palm kernel biodiesel (PKB) production using palm kernel oil (PKO) in an optimisation study using a definitive screening design. The AMS, SSC800 and SSC900 were characterised by Atomic Absorption Spectrophotometer (AAS), Brunauer-Emmett-Teller (BET) and Scanning Electron Microscopy (SEM). The AAS result revealed that the catalysts contained essential elements of Ca, Mg, Na, Si and K which are suitable for transesterification reactions in proportion of 66.67%, 1.12%, 2.06%, 3.01% and 9.33% for SSC800 respectively, and 59.33%, 1.03%, 2.30%, 2.50% and 8.00% for SSC900 respectively. The images of the catalysts revealed improved surface morphologies with larger porosities compared to that of the AMS, having surface areas of 244.2 m2/g and 230.9 m2/g for SSC800 and SSC900respectively. This justified the reason for the higher catalytic activity of the SSC800 compared to the SSC900. The optimisation study gave the optimal conditions for the optimum biodiesel yield of 98.28% as 6:1 MeOH: oil molar ratio, 3 h reaction time, 55oC temperature and 2% (w/w) catalyst quantity of SSC800. The fuel properties obtained for the PKB compared well with the ASTM standard of biodiesel and as such, it is a quality biodiesel suitable for compression ignition engines. Therefore, the Archachatina marginata snail-shell is an effective, suitable, natural and renewable material for catalysts development for commercial biodiesel production.