It was just last month that we heard how waste coffee grounds could be utilized to boost the strength of concrete. Well, new research shows that such otherwise-unwanted grounds could also be used to 3D-print plant pots, single-use cups and more.
Michael Rivera, who is an assistant professor of computer science at the University of Colorado Boulder, first got the idea when he saw that the used coffee grounds at his favorite café were simply going into the garbage.
Working with colleagues at the university, he proceeded to create a paste consisting of dried coffee grounds plus powdered cellulose and xanthan gums, which are mixed with water. All of these ingredients are food-safe and compostable.
The scientists proceeded to modify an existing 3D printer by adding a syringe filled with the paste, along with plastic tubing to deliver that paste to the build plate. Utilizing this setup, Rivera's team was able to print objects such as plant pots, pieces of jewelry, and even disposable espresso cups. What's more, when activated charcoal was added to the mix, the material became electrically conductive.
Once the printed paste has dried, it is reportedly about as tough as unreinforced concrete. That said, if an item made of the material gets broken or is otherwise no longer wanted, it can simply be ground back into powder and used to print new objects.
Additionally, the material will biodegrade if placed in the ground. This means that plant pots made of the substance could be used to grow seedlings of plants such as tomatoes, then just placed in the soil with the plants still in them once the plants get tall enough.
The research is described in a paper that was recently published in the journal Proceedings of the 2023 ACM Designing Interactive Systems Conference.
Other possible uses for waste coffee grounds include turning them into a carbon capture material, a biofuel ingredient, and sewage gas filters.
Source: University of Colorado Boulder