Coffee-infused foam removes lead from contaminated water

September 21, 2016
A foam filter made with used coffee grounds removes lead and mercury from contaminated water. Credit: American Chemical Society

Coffee is one of the most popular drinks in the U.S., which makes for a perky population—but it also creates a lot of used grounds. Scientists now report in the journal ACS Sustainable Chemistry & Engineering an innovative way to reduce this waste and help address another environmental problem. They have incorporated spent coffee grounds in a foam filter that can remove harmful lead and mercury from water.

Restaurants, the beverage industry and people in their homes produce millions of tons of used coffee grounds every year worldwide, according to researcher Despina Fragouli. While much of the used grounds go to landfills, some of them are applied as fertilizer, used as a biodiesel source or mixed into animal feed. Scientists are also studying it as a possible material for water remediation. Experiments so far have shown that powder made from spent coffee grounds can rid water of heavy metal ions, which can cause health problems. But an additional step is needed to separate the powder from the purified water. Fragouli and colleagues wanted to simplify this process.

The researchers fixed spent coffee powder in a bioelastomeric foam, which acted as a filter. In still water, the foam removed up to 99 percent of lead and mercury ions from water over 30 hours. In a more practical test in which lead-contaminated water flowed through the foam, it scrubbed the water of up to 67 percent of the lead ions. Because the is immobilized, it is easy to handle and discard after use without any additional steps, the researchers say.

Credit: American Chemical Society

Explore further: Used coffee grounds are a rich source of healthful antioxidants

More information: Asmita A. Chavan et al. Spent Coffee Bioelastomeric Composite Foams for the Removal of Pband Hgfrom Water, ACS Sustainable Chemistry & Engineering (2016). DOI: 10.1021/acssuschemeng.6b01098

Abstract
Herein we present an interesting approach for the reutilization of coffee waste in water remediation. This is achieved by the development of bioelastomeric foams composed of 60 wt % of spent coffee powder and 40 wt % of silicone elastomer using the sugar leaching technique. In this study, we present the necessary characteristics of the developed "green" foams for the successful removal of Pb2+ and Hg2+ ions from water, and we identify the involved mechanisms. The capability of the bioelastomeric foams to interact with Pb2+ and Hg2+ is not affected by the presence of other metal ions in water as tests in real wastewater demonstrate. The incorporation of the spent coffee powder in a solid porous support, without compromising its functionality, facilitates the handling and allows the accumulation of the pollutants into the foams enabling their safe disposal. The fabricated foams can be used for the continuous filtration and removal of metal ions from water, demonstrating their versatility, in contrast to the sole coffee powder utilized so far, opening the way for the reutilization and valorization of this particular waste.

Related Stories

How used coffee grounds could make some food more healthful

May 13, 2015

Coffee has gone from dietary foe to friend in recent years, partly due to the revelation that it's rich in antioxidants. Now even spent coffee-grounds are gaining attention for being chock-full of these compounds, which have ...

Could you run your car on coffee?

June 17, 2014

(Phys.org) —New research from our Centre for Sustainable Chemical Technologies shows that waste coffee grinds could be used to make biodiesel.

Waste coffee used as fuel storage

September 1, 2015

Scientists have developed a simple process to treat waste coffee grounds to allow them to store methane. The simple soak and heating process develops a carbon capture material with the additional environmental benefits of ...

Recommended for you

The birth of a new protein

October 20, 2017

A yeast protein that evolved from scratch can fold into a three-dimensional shape—contrary to the general understanding of young proteins—according to new research led by the University of Arizona.

Discovery lights path for Alzheimer's research

October 19, 2017

A probe invented at Rice University that lights up when it binds to a misfolded amyloid beta peptide—the kind suspected of causing Alzheimer's disease—has identified a specific binding site on the protein that could facilitate ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
2 / 5 (1) Sep 21, 2016
Because the coffee is immobilized, it is easy to handle and discard after use without any additional steps, the researchers say.


Of course then, the foam is full of lead and mercury so you can't just discard it.
optical
Sep 21, 2016
This comment has been removed by a moderator.
resinoth
not rated yet Sep 22, 2016
this removes 99% of lead ions after 30 hours... but I wonder:

are there Lead molecules suspended in these waters which are NOT ionized? Is it a minority percentage?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.