Abstract

The search for sustainable alternatives to petroleum diesel has sparked interest in biodiesel production from nonedible feedstocks. This study investigated biodiesel derived from Croton oil and waste cooking oil under optimized transesterification conditions (oil-to-methanol ratios 1:1 and 2:1, 60 °C, 400 rpm, 60 min). To further improve the fuel quality, biodiesel was blended with diesel and doped with carbon-based nanoparticles (50–100 ppm). Physicochemical characterization of the fuels and nanoparticles was conducted using Fourier Transform Infrared Spectroscopy, Gas Chromatography–Mass Spectrometry, Scanning Electron Microscopy, Transmission Electron Microscopy, and X-ray Diffraction. Conversion efficiencies were reported as 88.13% for Croton oil and 90.96% for waste cooking oil. Viscosity decreased from ~5 mm²/s to ~3.62 mm²/s while the calorific value improved from ~35 MJ/kg to ~40 MJ/kg in pure biodiesel and nanoparticle-doped blends respectively. These improvements demonstrate that nanoparticle-doped biodiesel diesel blends can offer sustainable alternatives to petroleum diesel.