Musa ABB (Kachkal) banana waste derived heterogeneous nanocatalyst for transesterification of binary oil mixture of Jatropha curcas and Pongamia pinnata to biodiesel

In this study, a post-harvest plant of Musa ABB, commonly known as ‘Kachkal’ was explored to prepare a catalyst and applied for jatropha pongamia oil methyl esters (JPOME) synthesis from Jatropha curcas and Pongamia pinnata oils blended in a 1:1 ratio. The peel and trunk of the plant were burnt to ashes and calcined at 550 °C for 1 h to achieve the desired catalysts. Sophisticated analytical approaches such as FESEM-EDX, XRD, FT-IR, BET, XPS, HRTEM, and TGA were implemented to characterize the prepared catalysts. The maximum biodiesel (JPOME) yield of 96.34 ± 1.30 % was secured in 10 ± 2 min by using calcined kachkal peel at 550 °C (CKP-550) as compared to using calcined kachkal trunk at 550 °C (CKT-550) (91.04 ± 2.06 % in 87 ± 15.39 min) under optimum conditions of 9:1 methanol to oil molar ratio (MOMR), 9 wt% catalyst dosage and 65 °C operating temperature. The reusability of CKP-550 was studied up to 3rd cycle achieving 81.57 ± 2.15 % biodiesel yield. The characteristic studies revealed the attendance of K as the main element (24.80 wt%) existing as carbonates and oxides in the catalyst. The analysis suggested the characteristics of mesoporous substances in the nanocatalyst (5.68 ± 1.43 nm). The turnover frequency (TOF) and basicity of CKP-550 were 36.86 h⁻¹ and 0.47 mmol g⁻¹, respectively. Investigations into the kinetic and thermodynamics of JPOME synthesis reactions catalyzed by CKP-550 indicated that these processes are endothermic and non-spontaneous. The activation energy (E_a) was quantified to be 41.705 kJ mol⁻¹ and the reaction followed pseudo-first-order kinetics. In brief, waste banana (Musa ABB) peel is a viable, sustainable, and cost-effective catalyst for biodiesel synthesis from non-edible oil blends, offering a novel solution for mitigating air pollution from diesel vehicles.