Dyes, such as those used in the textile industry, are a major environmental problem.
Dyes, such as those used in the textile industry, are a major environmental problem. At TU Wien, efficient filters have now been developed – based on cellulose waste.
Using waste to purify water may sound counterintuitive. But at TU Wien, this is exactly what has now been achieved: a special nanostructure has been developed to filter a widespread class of harmful dyes from water. A crucial component is a material that is considered waste: used cellulose, for example in the form of cleaning cloths or paper cups. The cellulose is utilized to coat a fine nano-fabric to create an efficient filter for polluted water.
Colored Poison in the Water
Organic dyes represent the largest group of synthetic dyes, including so-called azo compounds. They are widely used in the textile industry, even in countries where little attention is paid to environmental protection, and the dyes often end up in unfiltered wastewater. "This is dangerous because such dyes degrade very slowly, they can remain in the water for a long time and pose great danger to humans and nature," says Prof. Günther Rupprechter from the Institute of Materials Chemistry at TU Wien.
There are various materials that can bind such dyes. But that alone is not enough. "If you simply let the polluted water flow over a filter film that can bind dyes, the cleaning effect is low," explains Günther Rupprechter. "It's much better to create a nanofabric out of lots of tiny fibers and let the water seep through." The water then comes into contact with a much larger surface area, and thus many more organic dye molecules can be bound.
Read more at Vienna University of Technology
Image: Günther Rupprechter and Qaisar Maqbool with a visualization of the nano web. (Credit: Vienna University of Technology)
