NCSU
The left vial shows dye solution in water (blue) and the right vial shows clear water after the dye was removed from the solution by the polymer (Source: Januka Budhathoki-Uprety, NCSU)
A synthetic polymer that can remove certain dyes from water, and that can be recovered and reused, has been demonstrated by researchers of the North Carolina State University. These findings offer a new potential method for cleaning wastewater e.g., in the textile industry.
In the study, published in ACS Applied Polymer Materials, a synthetic polymer called polycarbodiimide has been developed. The researchers of the North Carolina State University, Raleigh, NC/USA, then tested the material’s ability to clean wastewater first by dissolving it in a solvent, and then mixing it with water contaminated with dyes. They tested the polymer solution against a series of 20 anionic dyes, also called acid dyes, which are used in the textile industry. For initial assessments, the researchers did a visual test with the naked eye to see if the polymer worked. Later how well the polymer removed the colorant has been done using UV-Vis spectroscopy.
“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. 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.” Januka Budhathoki-Uprety, assistant professor of textile engineering, chemistry and science at NCSU
The polymer solution removed all but 4 of the 20 acid dyes they tested. In addition, it could be shown that it was easy to recover the polymer within minutes. Characteristics of the dyes – related to their molecular structures – could be found that contributed to whether the polymer worked or not.
In future studies, researchers are planning to develop a library of polymers that would have the potential to work with more types of dyes. In addition, they want to develop a more practical mechanism for using polycarbodiimide to clean wastewater.
In the study, published in ACS Applied Polymer Materials, a synthetic polymer called polycarbodiimide has been developed. The researchers of the North Carolina State University, Raleigh, NC/USA, then tested the material’s ability to clean wastewater first by dissolving it in a solvent, and then mixing it with water contaminated with dyes. They tested the polymer solution against a series of 20 anionic dyes, also called acid dyes, which are used in the textile industry. For initial assessments, the researchers did a visual test with the naked eye to see if the polymer worked. Later how well the polymer removed the colorant has been done using UV-Vis spectroscopy.
“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. 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.” Januka Budhathoki-Uprety, assistant professor of textile engineering, chemistry and science at NCSU
The polymer solution removed all but 4 of the 20 acid dyes they tested. In addition, it could be shown that it was easy to recover the polymer within minutes. Characteristics of the dyes – related to their molecular structures – could be found that contributed to whether the polymer worked or not.
In future studies, researchers are planning to develop a library of polymers that would have the potential to work with more types of dyes. In addition, they want to develop a more practical mechanism for using polycarbodiimide to clean wastewater.
