Exceptional room temperature catalytic transesterification of waste cooking oil to biodiesel using environmentally-benign K2CO3/γ-Al2O3 nano-catalyst

This study addresses the exceptional catalytic efficacy of K2CO3/gamma-Al2O3 as a heterogeneous nano-catalyst for room-temperature biodiesel production from waste cooking oil (WCO). That is industrial aluminum waste powder (IAWB) is used as a precursor for the synthesis of environmentally benign nano-supporting alumina (gamma-Al2O3) which is subsequently loaded with K2CO3. Diverse analytical techniques are applied to study the physicochemical characterization of the prepared nano-catalyst, e.g., XRD, XPS, FT-IR, BET isotherm, CO2- TPD, SEM-EDX, HR-TEM, and AFM. The Box-Behnken Design (BBD) approach is implemented to optimize the parametric conditions for the transesterification reaction via applying Response Surface Methodology (RSM), i.e., catalyst loading, reaction time, and methanol:oil (M:O) molar ratio. The optimum transesterification reaction conditions for biodiesel conversion (98.7%) are 5.8 wt% catalyst loading at 25 degrees C for 120 min with a 9:1 M:O molar ratio, which is superior to similar repeating catalysts. Kinetic and thermodynamic parameters are esti-mated, with activation energy (Ea), activation enthalpy (Delta H#), and activation entropy (Delta S#) values of 18.87 kJ mol-1, +16.34 kJ mol-1, and-217.22 J mol-1, respectively. The catalyst maintains its catalytic activity for six successive cycles. Moreover, the physicochemical characterization of the generated biodiesel fuel is congruent with the ASTM D -6751 and EN -14,214 international standards. Thus, the proposed catalyst herein is a potential heterogeneous catalyst with robust activity for industrial biodiesel manufacture.