Alkaline batteries are widely used in contemporary society. However, their black powder, which contains metals, categorizes them as hazardous waste, posing environmental risks if not disposed of correctly. Similarly, waste cooking oil (WCO), frequently produced in homes and restaurants, is often discarded into the environment as waste. In this study, the spent black powder from alkaline batteries was effectively utilized as a catalyst for biodiesel generation from WCO. This catalyst, containing carbonaceous materials, MnO