Exploring the potential of novel feedstock (Caesalpinia bonduc seeds) for circular biodiesel production using seed shell-derived green nanocatalysts

Abstract

Current work focuses on the investigation of newly explored Caesalpinia bonduc (L.) seed oil as an efficient and oil rich (45 % w/w) source for producing user friendly biodiesel during transesterification reaction. The whole process was facilitated using green nanocatalyst (K₂O) synthesized from discarded Caesalpinia bonduc seed coat as reducing agent. About 98.27 % Caesalpinia biodiesel yield was attained with 1:6 oil to methanol, 0.15 (wt. %) K₂O nanocatalyst at 120 °C temperature and 120 min interval. GCMS studies of Caesalpinia biodiesel depicts the presence of seven major peaks with retention time (12.640, 17.072, 18.722, 18.816, 18.981 and 23.921 min) confirms the successful conversion of Caesalpinia oil to corresponding biodiesel. The fuel properties of Caesalpinia biodiesel were 70 °C Flash point, 0.36 mgKOH/g Acid number, 0.89 kg/L Density, 3.52 Kinematic viscosity, 0.0063 % Sulphur, −12 °C Pour point, −8 °C Cloud Point are in excellent hormony with global bifuel standards. The green K₂O nanocatalyst exhibits excellent reusability for up to 9th runs exhibiting its maximum reactivity up to three cycles. The outcomes of this investigation led to the conclusion that the non-conventional and non edible oil seeds of Caesalpinia bonduc (L.) Roxb and green K₂O nanocatalyst is a viable, low-cost and sustainable and highly reactive contenders for future biodiesel industry with the potential to mitigate energy glitches along with positive and healther socio economic wellbeing of community at global level.