Researchers Mix Chemistry & 3D Printing to Study Ways to Remove Pollutants from Air, Water, Environment

3D printing appeals to so many users on so many different levels, and whether or not you were previously interested in materials sciences, once you begin fabricating from any 3D printer you will find that you suddenly have a keen interest in what you can feed the 3D printer in order to make an array of different products. From engineers to architects to jewelers, there’s a continual supply of new hardware, software, and materials to propel along infinite options for creating. As you delve into more alternative materials you will also generally find that equipment becomes more complex and price tags more steep.

If 3D printing was made to appeal to one certain group though, for sure it’s all those science buffs and technogeeks out there. Many of you were probably good at chemistry or perhaps even enjoy it—and if so, here’s a great new idea to meld that interest with 3D printing—as well as seeing how problems are solved—and sometimes, very important ones. Researchers at American University have recently discovered a way to create structures with active chemistry while 3D printing commercially.

Matthew Hartings

The study was led by Matthew Hartings, an American University chemistry professor, and he and his team have published their findings in Science and Technology of Advanced Materials with the article ‘The chemical, mechanical, and physical properties of 3D printed materials composed of TiO2-ABS nanocomposites,’ authored by Matthew R. Skorski, Jake M. Esenther, Zeeshan Ahmed, Abigail E. Miller and Matthew R. Hartings.

“These experiments display chemical reactivity in nanocomposites that are printed using commercial 3D printers, and we expect that our methodology will help to inform others who seek to incorporate catalytic nanoparticles in 3D printed structures,” state the researchers in their paper.

The researchers took a small, simple plastic structure and doused it with chemically active titanium dioxide (TiO₂) nanoparticles.

“TiO₂ nanoparticles make an ideal test case for an inorganic nanoparticle filler within thermoplastic printing filaments,” state the researchers in their paper. TiO₂ is a known photocatalyst, capable of generating free radical species in both aqueous and organic solvents and in the presence of oxygen upon irradiation.”

 

“The band gap of TiO₂ corresponds to UV wavelengths. Upon absorbance of light, electrons in the conduction band can form superoxide radicals from adsorbed oxygen, and holes in the valence band can form hydroxyl radicals from water. Because of these properties, TiO₂ has potential applications in the photocatalytic removal of pollution from air, water, and agricultural sources.”

Taking a standard 3D printing filament, they added the nanoparticles and printed a small plastic matrix. In doing this, their experiment asked two questions:

1. Would the nanoparticles stay active in the structure once printed?
2. Created for pollution mitigation, would the matrix perform?

In both cases, the answer was yes, proving that the pollutants would break down as natural light mixed with TiO₂. The researchers state that you can indeed try something like this at home if you are interested in finding out more about this experiment that, according to the study, has great potential in future applications for removing air, water, and agricultural pollution.

Further, when examining mitigation of the pollution, the researches took the matrix—in a very simple shape—and immersed it in water with a pollutant, in the form of an organic molecule. It was succinctly ‘destroyed,’ according to the researchers, who stated that TiO₂ also photocatalyzed the degradation of a rhodamine 6G 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.

The structure could not print, however, if the nanoparticle concentration was any higher than 10 percent of the structure’s total mass. According to Hartings, a higher concentration could be needed for a better structure. Depending on the need, “ten percent might be okay,” he said.

While the first experiment was centered around a very simple shape, the researchers are planning to advance to more complex shapes to see how the chemical reactivity is affected. They have begun working with a variety of other geometries already.

“We expect to expand upon these studies by incorporating other, chemically active nanoparticles within ABS and bring new chemistry to 3D printed materials,” state the researchers in their paper.

The ultimate goal will be to explore the potential for 3D printing and applications that involve photocatalytic removal of environmental pollutants. This experiment also, according to the researchers in their recent press release, was created with many off-the-shelf materials, and “puts the power of chemistry invention into the hands of people taking advantage of the 3D printing revolution.” Is this something you might be interested in trying? Discuss in the 3D Printing with Chemistry forum over at 3DPB.com.

FTIR spectra for printed TiO2-ABS composites. The top panel includes the full spectrum for each composite, averaged over 10 printed samples. The bottom panel displays the % transmittance at wavelengths associated with the different components for the TiO2-ABS composites. The error bars correspond to the standard deviation from the averaged measurement over all spectra acquired.