3D printers have been used to create a lot of things, many of them helpful to human health and the environment, but the materials used in the printing process have always been, themselves, inert. Materials like metal, clay and, most of the time, ABS plastic, are extruded by the machines to build something one layer at a time. The resulting object fills a need, but not through its chemistry, but by its function. Researchers at American University decided to change that.
The researchers, led by American University chemistry professor Matthew Hartings, created an ABS plastic filament with an active chemistry capable of neutralizing pollutants.
To make the filament, they added chemically active titanium dioxide (TiO2) nanoparticles to the usual plastic filament and fed it into a 3D thermoplastic printer. The material was used to print a matrix design the size and appearance of a household sponge. The resulting structure was still active even after the printing process.
When natural light interacts with TiO2, a reaction occurs that breaks down pollutants. To test if the printed sponge could clean polluted water, they placed it in water with an organic pollutant and it destroyed the pollutant. The researchers see this success as opening the door to other active 3D-printed objects that could serve a variety of purposes.
"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.
Right now, the material can only be successfully printed at a concentration of 10 percent nanoparticles. A higher concentration would probably be needed for serious pollution control, but with improvements, this material could have a lot of applications for keeping water, air and agricultural pollution under control.
The team is working on printing the material into many different types of shapes to see if certain shapes affect the chemical reactivity and to see which shapes best perform against environmental pollutants.
Their work was just published in the journal Science and Technology of Advanced Materials.