Waste Coffee Grounds as Potential Biodiesel Source

University of Cincinnati researchers were able to extract oil from waste coffee grounds collected from a campus cafe and converted it to biodiesel. After oil extraction, they produced activated carbon from the dried coffee grounds and used it as filter material to remove the impurities in crude biodiesel.

An estimated one million metric tons of waste coffee grounds is generated in the U.S. alone, and most of this waste is dumped into landfills. The promising discovery reported at the 246th National Meeting & Exposition of the American Chemical Society (ACS) would not only open landfill space, but it also offers an alternative source of biodiesel without compromising the food supply. Biodiesel is typically manufactured from food crops such as corn and soybean.

The researchers reported that the highest oil yield from waste coffee grounds was almost 20 percent, and the biodiesel made from this oil has met industry standards. The efficiency of coffee grounds-derived activated carbon as purification material for crude biodiesel was slightly lower compared with commercial purification products. With more opportunities for improvement, UC researchers find it as a promising alternative material for biodiesel purification, considering the cost of commercial filters. Future research will focus on improving its purification efficiency.