Environment

Coffee grounds recycled as carbon capture material

Coffee grounds recycled as car...
Don't throw those grounds away – they could be used to filter methane from the atmosphere
Don't throw those grounds away – they could be used to filter methane from the atmosphere
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Don't throw those grounds away – they could be used to filter methane from the atmosphere
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Don't throw those grounds away – they could be used to filter methane from the atmosphere

Coffee grounds are not exactly noxious despoilers of the environment, but many millions of tons of them are generated every year and simply disposed of with other vegetable matter and food waste. Now, researchers have devised a way to utilize this innocuous waste product to get rid of a much more dangerous one. By modifying used coffee grounds into a carbon capture material, the new product may provide a simple, inexpensive way to remove a prolific and harmful greenhouse gas from the atmosphere.

Working at the Ulsan National Institute of Science and Technology (UNIST) in South Korea to develop the new material, researchers steeped used coffee grounds (100 percent Colombian coffee, dark roast, fine ground) in a potassium hydroxide solution and heated the resulting mixture to 65 °C (149 °F) and stirred it for 24 hours. This concoction was then dried in an oven at 100 °C (212°F), before finally being transferred to an argon-atmosphere furnace where it was subjected to temperatures of 700-900 °C (1,290 - 1,650 °F) to activate its carbon-capture properties.

This resulted in the production of a stable carbon capture material in under a day, which the researchers claim is much quicker than the time taken for the production of other carbon capture materials.

"The big thing is we are decreasing the fabrication time and we are using cheap materials," says Christian Kemp, an original researcher on the work at UNIST and now a member of the Pohang University of Science and Technology faculty. "The waste material is free compared to all the metals and expensive organic chemicals needed in other processes – in my opinion this is a far easier way to go."

Slated for use as a capture material for the greenhouse gas methane, Kemp clams to have thought about using activated coffee grounds whilst looking into a cup of coffee whilst conversing with UNIST colleagues about another project.

"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?'" says Kemp.

The absorbency of coffee grounds after activation was found to be exceptionally good, according to the researchers, showing great gas adsorption under pressure. The large micropore volume and surface area in such a non-crystalline adsorbent and its influence on gas adsorption capacity is not fully understood at present, as the researchers freely admit, but the incorporation of sodium hydroxide may well be the major factor in successful activation of the coffee grounds for carbon capture.

"It seems when we add the sodium hydroxide to form the activated carbon it absorbs everything," says 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."

According to the researchers, the new material may also have an added advantage to capturing and storing methane from the atmosphere in that – after it has absorbed its fill – it could then be used as a fuel itself with much cleaner-burning properties than other fossil fuels.

As part of the research, the team also demonstrated the ability of the new material to store hydrogen at cryogenic temperatures (-150 °C/-238 °F to absolute zero), with a view to an eventual goal of developing hydrogen storage in the activated coffee grounds at higher temperatures to make the product more practical for common applications.

The results of this work were recently published in the journal Nanotechnology.

Source: IOP

14 comments
christopher
LOL - let's burn a ton of carbon to create something that sequesters a gram! For their next trick, they're going to cure sea level rise by preventing one drop of rain from returning to the ocean. I'm not sure what's worse - the rank arrogance of people who think that their "making a difference" will ever be noticed, or the utter incomprehension that exists in almost everyone's minds when it comes to the concept of "big numbers". Can anyone really grok 3000gigatonnes?
Nik
A little research into reality, not propaganda, of CO2, would show that it is not a significant 'greenhouse gas' never has been, and never will be. The Earth has had an atmosphere with Twelve Times the current CO2 level in the past, [carboniferous age] was it a greenhouse? No, it was an ice age. Mars receives about half the energy from the sun as earth, but it has 2,400 times as much CO2, is it a greenhouse? No. The main greenhouse gas on earth is water vapour, Mars has non, so it is not a greenhouse, in spite of its enormous atmospheric CO2 content. The CO2 myth was started by Maggie Thatcher to justify her closing down coal pits, and to bring in Nuclear power, then someone had the bright idea of Carbon Tax. Have you ever known a politician tell lies? Have you ever known one to tell 'The truth, The whole truth, and nothing but the truth?' If you have, then I would believe in fairies and hobgoblins.
mgb
Have to agree with Christopher. OTOH, Coffee grounds are excellent for masking the smells of poo, whether human or animal. A dairy farmer in Japan get them for free from his nearby canned coffee plant and sprinkles them generously on the straw bedding for his cows, solving the odor problem that was upsetting his neighbors. It can also be used in dry composting toilets for the same purpose. such toilets can be designed to harvest the emitted methane to burn as a fuel (a dry methane digester).
Julien Fournier
Nik: You fail. Mars has a thin atmosphere, it's really small compared to to earth's atmosphere. There is a very low potential to keep that energy, it will go back to space really quickly. Earth has more way to store that energy. It's thick atmosphere, its oceans, its forests.
Omen
Hmmm? How much gas was created to heat the coffee to temperatures of 700-900 °C (1,290 - 1,650 °F)? And mgb, the Carboniferous Era was about as far from an Ice Age as one can get. Please check sources.
dsiple
Just dump them under a rosebush where you get a win/win solution. The roses love them. Or toss it into your compost pile. All the rest described above is just make-work. First you have to get all of the Starbuck's on board to save them all for you, then, work, work, more work………...
SuperFool
Coffee grounds work as a hand cleaner like pumice. mix in some dish washing detergent and it cuts through automotive grease with no sweat. Paint, glue and tar take more effort but still come off.
Kpar
'"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?'" says Kemp.' I do not buy into the anti-CO2 hysteria, but this seems like an interesting approach to capture and use methane, as opposed to just letting it vent into the atmosphere. Energy is energy, and the more efficiently we use it, the cheaper it should get...
PeterOsborne
Carboniferous was warmer than today because there was no land mass over either pole to cool things down. We are in an ice age now , the warm part, and there is a land mass at the South pole, Antarctica. We will return to cold relatively soon, say 2,000 years or so.
Buellrider
So if I eat the coffee grounds I sequester my own emissions and vibrate off all excess weight and quite possibly walk through walls. Cool.