When discussing sustainability efforts, most people think about recycling and limiting one’s carbon footprint.
Although, two researchers at Texas Tech are working to understand how to eliminate toxic dyes found in disposed wastewater.
Disposing textile dyes in wastewater has become a prominent factor in environmental pollution, according to a research article “Impact of Textile Dyes Waste on Aquatic Environments and its Treatment.” This issue has spread because of the increase in demand for textile products, which led to the increase in the number of textile mills.
Lihua Lou, environmental toxicology doctoral candidate from Henan, China, is one of the researchers who is conducting a study, which she said started in September 2016. The focus of the research is to understand how to filter and eliminate toxic fabric dyes used in the textile industry.
“Only around 20 percent of dyes attach to clothes,” she said. “80 percent still remains in the water. That’s the reason textile industries consume a lot of water, and they generate a lot of the water pollutant to the environment.”
Seshadri Ramkumar, professor of advanced materials in the Tech Department of Environmental Toxicology, said Lou is conducting the research in his lab, which focuses on fibers, such as cotton, for new applications. The research consists of utilizing nanofibers to make filters that will separate toxic dyes from wastewater and eliminate those dyes.
“The mission is to produce environmentally-friendly materials that will help society,” he said. “This is a good example of mission-linked research coming out of Texas Tech.”
The nanofiber used for the filters, which do not dissolve in water, is made up of polyvinylidene fluoride (PVDF) added with the nanoparticle titanium dioxide, Ramkumar said. When exposed to visible rays, PVDF and the titanium dioxide will degrade the toxic dye, Rhodamine B (RhB).
Regarding the degradation process, Ramkumar said Lou wanted to make the filter active.
“Normally, when you have to degrade a material, you need to have some additional energy put onto it,” he said. “You have a filter, which is not new, even though the nano is a new technology, then you add some material into it. Make it function, make it active.”
An external source is needed to excite the functional material, Ramkumar said. Once the material is excited, it will react with the toxin.
“Normally, in these circumstances, people use ultraviolet rays, which are relatively expensive when you have to generate these ultraviolet rays,” he said regarding how Lou wanted to find an alternative to ultraviolet rays. “Previously, people have worked with ultraviolet rays, whereas our lab is focused on using the sun’s rays.”
Visible light generates degrading oxidants, which Ramkumar said eliminates the toxicity from the dyes. He said the higher number of functional particles the better for degradation.
Despite the success of figuring out how to eliminate RhB, there could be other obstacles that need to be overcome throughout the research process.
“We have proven the success in the lab, but it has to be scaled up if it has to be commercial,” he said. “But what I have seen now, based on Lou’s work, is even though nanofibers are the best substrate, they may be expensive, but we are on the lookout for high surface-area materials, such as meltblown. What the work found is if we could manipulate the functional particles and then the surface area, you are able to gain the advantage of developing a highly efficient filter.”
To scale up the work for commercial use, a variety of other requirements may need to be fulfilled.
“We wanted to try different dyes because, right now, we’re only doing Rhodamine B,” Lou said. “We also want to try different combinations of dyes. In textile industries, it may combine a lot of this stuff, so we want to try all the possibilities.”
The pollution caused by toxic dyes is an issue Lou said this research is aimed at resolving.
“The dye degradation is one of the difficult tasks in the textile industry,” she said. “It’s very hard to remove that in an environmentally clean way.”
Regarding the research, Ramkumar said him and Lou are able to present how fiber research can benefit the environment.
“The aim of the lab is to develop products that are environmentally-friendly and help to protect the environment to improve human life,” he said. “This project is a direct example of how fibers can be used to develop products that will protect human beings as well as marine environments.”
When considering the textile industry’s contribution to environmental pollution, one may wonder how textile mills continue to utilize toxic dyes for coloring fabric.
Kanti A. Jasani, president of Performance and Technical Textile Consulting, said water, energy and chemicals and dyes are the factors necessary for textile mills to add color to undyed fabric. He said chemicals are used to put dye on fabric.
Depending on that fiber process and the type of fiber, Jasani said a little bit of dye may not stick to the fabric or a lot of dye may not stick to the fabric. He said the dye that does not stick is disposed in wastewater.
Despite the amount of pollution toxic dyes create, Jasani said the research Lou and Ramkumar are conducting needs to be applied in order to work toward diminishing pollution caused by textile mills.
“Any research is only as good as its adaptation, its practical application,” he said.
In some fields, Jasani said not all research is adapted. Although, he said the nanofiber filter research at Tech is one that can be beneficial in the future.
“Some research, like this one, really shows tremendous promise,” he said.
To get this research applied, Jasani said people need to learn about the research and its benefits.
“As much exposure that this research and the benefits of utilizing this technology is given, the better it will be understood by the people,” he said. “The better it is understood, the better the chance of adapting something like this.”
Informing people of the progress and success of this research may have a variety of benefits.
The research is getting published as a cover-page article in a high impact scientific journal, Ramkumar said. In addition to this recognition, he said Tech is a key institution in fiber research.
“Texas Tech’s priority is to make this a preeminent center in world for fiber research,” he said. “This research is clearly feeding to the goal of TTU.”