Waste Musa paradisiaca plant: An efficient heterogeneous base catalyst for fast production of biodiesel

Abstract

Exploration of economically viable and environmentally benign solid base-catalyzed transesterification of oil is extremely important to significantly reduce the cost of biodiesel. In this study, heterogeneous base catalysts from the peel, trunk and rhizome of Musa paradisiaca (Malbhog) were prepared by burning the dry materials followed by calcination at 550 °C for 2 h. The catalysts were investigated for biodiesel production using jatropha oil as a feedstock. Catalysts were characterized using powder X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), Brunauer–Emmett–Teller (BET), Energy dispersive X-ray (EDX), Field emission scanning electron microscope (FESEM), X-ray photoelectron spectrometer (XPS) and HRTEM (High resolution transmission electron microscope). EDX and XPS studies exhibited that M. paradisiaca trunk catalyst possessed higher potassium content than the peel and rhizome catalysts. M. paradisiaca trunk catalyst displayed better efficacy which yielded 97.65% of biodiesel at 65 °C only in 9 min of reaction time using 5 wt % of catalyst and 9:1 MTOR (methanol to oil ratio). Basicity of catalyst was found in the increasing order of 1.39 mmol g−1 (rhizome) < 1.43 mmol g−1 (peel) < 1.59 mmol g−1 (trunk) with turnover frequency of 46.16 min−1 (rhizome) < 56.85 min−1 (peel) < 68.24 min−1 (trunk). Activation energies using M. paradisiaca peel, trunk and rhizome catalysts were found to be 48.68, 47.56 and 48.93 kJ mol−1. All the three catalysts from the waste M. paradisiaca plant are contributing almost similar activities in the catalysis with remarkable efficacies. The catalyst was successfully reused up to the 3rd reaction cycle with 91.23% of biodiesel yield. Biodiesel was characterized using FT-IR, 1H NMR, 13C NMR and GC-MS. Biodiesel properties and its (Na + K) and (Ca + Mg) concentrations were found to be within the limit of ASTM D6751 and EN 14214 standards. This study will provide a low-cost, renewable and eco-friendly heterogeneous base catalyst for efficient biodiesel production at a large-scale.