Can used coffee grounds help clean up environmental toxins?

Global coffee consumption generates millions of tons of spent coffee grounds each year, which can be damaging to wildlife and the environment.

However, new research reveals that spent coffee grounds could be repurposed to act as a powerful adsorbent of bentazone, a herbicide commonly used in agriculture that is highly neurotoxic.

Bentazon is a selective herbicide as it only damages plants unable to metabolize the chemical. It is considered safe for use on alfalfa, beans (with the exception of garbanzo beans), maize, peanuts, peas (with the exception of blackeyed peas), pepper, peppermint, rice, sorghum, soybeans and spearmint; as well as lawns and turf. Bentazon is usually applied aerially or through contact spraying on food crops to control the spread of weeds occurring amongst food crops.

In the study, investigators found that when they used zinc chloride to activate the carbon from spent coffee grounds, the activated carbon showed a 70% efficiency in bentazone removal. The activated carbon was also efficient in a high-sensitivity test for pollutants in water. "Spent coffee grounds... represent an opportunity to contribute to a circular economy," the authors wrote.

Image source: CC0 Public Domain.