Abstract A gradual shift to biofuels development was considered advantageous in reducing the pollution and other challenges associated with fossil fuels. Specifically, biodiesel production is one of those options prioritized in the literature. Herein, we demonstrated how a modified activated charcoal sample and chromium oxide can catalyze the upgrading of groundnut oil into fuel-grade biodiesel at the laboratory scale via trans-esterification with methanol. The charcoal-based catalyst was ...