3D-printed structure to mitigate pollution

For the first time, researchers have used commercial 3D printers to create a chemically active structure the size of handheld sponge that acts to mitigate pollution.
The experiment, created with many off-the-shelf materials common to makers, hobbyists and home enthusiasts, puts the power of chemistry invention into the hands of people taking advantage of the 3D printing revolution, researchers said.
The researchers led by Matthew Hartings, professor at the American University, designed a small structure the size of handheld sponge.
They dispersed throughout plastic chemically active titanium dioxide (TiO2) nanoparticles. Using the same filament hobbyists use in the printing process of 3D-printed figures, researchers added the nanoparticles.

Using a 3D thermoplastic printer, ubiquitous in manufacturing, the researchers printed a small, sponge-like plastic matrix.
Pollutants break down when natural light interacts with TiO2, which has potential applications in the removal of pollution from air, water and agricultural sources.

To demonstrate pollution mitigation, they placed the matrix in water and added an organic molecule (pollutant). The pollutant was destroyed. TiO2 also photocatalysed the degradation of a rhodamine 6G, a highly fluorescent dye in solution.
"It's not just pollution, but there are all sorts of other chemical processes that people may be interested in. There are a variety of nanoparticles one could add to a polymer to print," Hartings said.

One limitation of the research is that for the structure to print, the concentration of nanoparticles needed to be less than 10 per cent of total mass of the structure.
To have an efficient structure, a higher concentration could be needed, Hartings said.
The structure printed for this study was a simple shape. Harnessing the power of 3D-printing, the researchers' next step will be to print many exotic shapes to understand how printed structure affects the chemical reactivity.
Because of the promising results, they have already started experimenting with different printed geometries to determine an optimal printed shape for applications that involve photocatalytic removal of environmental pollutants.

The study was published in the journal Science and Technology of Advanced Materials.