Could your morning coffee help reduce air pollution?

January 23, 2017

It’s a morning ritual that’s played out in every corner of the world, but what happens to the 16 billion pounds of coffee grown every year after it’s gone through your filter? Scientists have actually been putting that brown sludge to good work, and our air and the planet, may become cleaner as a result.

Researchers have figured out a way to turn coffee grounds into an activated carbon material that can capture methane, a widespread, very problematic greenhouse gas. When methane is allowed to leak into the air, it absorbs the sun’s heat, warming our atmosphere. Methane comes from many sources, the largest of which are industrial emissions.

Activated carbon has actually been used in air and water purification for thousands of years. Traditionally, it’s made by heating nutshells, coconut husk or wood at high temperatures. The process creates a vast network of pores that attract and soak up chemicals, odors and gases. Only a handful of activated carbon can soak up a football field worth of pollutants. However, depending on the source material used, processing times can vary. The coffee, it seems, had a time advantage too.

"The big thing is we are decreasing the fabrication time and we are using cheap materials," said Christian Kemp, a researcher on the work at the Ulsan National Institute of Science and Technology (UNIST) in South Korea. "The waste material is free…in my opinion this is a far easier way to go."

The researchers soaked the 100% Colombian dark roast, fine ground coffee grounds in a potassium hydroxide solution and heated the resulting mixture to 149 °F. It was then dried and placed in a furnace exposing it to temperatures of 1,290 - 1,650 °F. This activated the carbon coffee grounds opening up those pores and fissures that remove pollutants.

The process took less than a full day, much quicker than other materials. The absorbency of this coffee-carbon was also found to be very good, helped along by the sodium hydroxide (also known as lye and caustic soda).

"It seems when we add the sodium hydroxide to form the activated carbon it absorbs everything," said Kemp. "We were able to take away one step in the normal activation process, the filtering and washing, because the coffee is such a brilliant absorbent."

If you’re wondering how they came upon this idea Kemp says:

"We were sitting around drinking coffee and I looked at the coffee grounds and thought ‘I wonder if we can use this for methane storage?'"

Wow. And you thought motivating you out of pajamas was coffee’s only superpower.

More Coffee Trivia:

Food giant Nestlé uses coffee grounds as a heat source in its factories

Starbucks is working with researchers to turn coffee grounds into plastic and laundry detergent.

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