Potato peels as a sustainable source for biochar, bio-oil and a green heterogeneous catalyst for biodiesel production

Abstract

The sustainable processing approach has been followed to transform the potato peel as the potential source for bio-oil and green heterogeneous catalysts. The byproduct (biochar) obtained from the thermochemical conversion was reused as a green, renewable and sustainable source for heterogeneous catalysts. The alkali and alkaline-rich biochar was recovered and transformed into bio-based mixed metal oxide and carbonates through calcination. The catalyst was characterized with the Energy Dispersive X-Ray Analysis, Fourier Transform Infrared, Brunauer–Emmett–Teller, X-Ray Diffraction, Field Emission Scanning Electron Microscope, and Transmission Electron Microscopy. The best operating temperature for pyrolysis was found to be 500°C, which produced the highest bio-oil (23.60%) and relatively high bio-char (29.50%). The synthesized catalyst showed high catalytic activity due to high potassium content (36.54%) in oxide and carbonate form. The maximum oil conversion (97.50%) was obtained using the optimized parameters: temperature 60 °C; 9:1 methanol to oil ratio; time 2 h, and catalyst loading 3 wt%. The integrated catalyst synthesizing method helped to valorize the food waste to high value-added products like biochar and bio-oil, which have the property of fuel and platform chemicals. Moreover, as the catalyst is derived from biomass, it is more environmentally benign, sustainable, and recyclable.