Researchers from North Carolina State University demonstrated that a synthetic polymer can remove specific dyes from water and that the polymer can be recovered and reused.
The findings suggest a new potential method for cleaning wastewater after it has been used in textile, cosmetic, or other industries.
Here’s what Januka Budhathoki-Uprety, lead author of a paper on the work and an assistant professor of textile engineering, chemistry, and science at NC State said in a press release:
“Dyes are used everywhere, including in the textile industry, as well as in pharmaceuticals, cosmetics, paper, leather, and even in medicines,”
“If these contaminants aren’t properly removed from wastewater after dyeing and finishing, they can be a significant source of environmental pollution and pose risks for human health.”
The full process
Researchers created a synthetic polymer called polycarbodiimide in a study, which was published in ACS Applied Polymer Materials. The researchers then put the material through its paces by dissolving it in a solvent and then mixing it with dye-contaminated water.
They tested the polymer solution against a set of 20 anionic dyes, also known as acid dyes in the textile industry. To see if the polymer worked, the researchers performed a visual test with their naked eyes. They then used UV-Vis spectroscopy to determine how well the polymer removed the colorant.
“We mixed the polymer solution and dye-contaminated water so the polymer in the solution can grab on to the dye. This is a two-phase solution, just like oil and water. The polymer part of the solution grabs onto the dyes,” Budhathoki-Uprety added.
“Then we were able to easily separate the clean water from the contaminated solution mixture by draining it out, similar to separation of water from a mixture of oil and water.”
All but four of the 20 acid dyes tested were removed by the polymer solution. Furthermore, they discovered that the polymer could be recovered in minutes. According to the release, they discovered dye properties – related to their molecular structures – that contributed to whether the polymer worked or not.
In the future, researchers hope to create a polymer library that will be able to work with a wider range of dyes. They also want to create a more practical mechanism for cleaning wastewater with polycarbodiimide.
The Textile Engineering, Chemistry, and Science Department at NC State funded the research. Individual researchers were also aided by NC State’s Office of Undergraduate Research’s Federal Work Study Research Assistant Program.