Researchers at Chalmers have developed a new bio-based material, a form of powder based on cellulose nanocrystals to purify water from pollutants, including textile dyes.
When the polluted water passes through the filter with cellulose powder, the pollutants are absorbed, and the sunlight entering the treatment system causes them to break down quickly and efficiently. Laboratory tests have shown that at least 80% of the dye pollutants are removed with the new method and material, and the researchers see good opportunities to further increase the degree of purification.
»There is great potential to find good water purification opportunities with this material.«
Gunnar Westman, Associate Professor of Organic Chemistry, Chalmers University of Technology
Clean water is a prerequisite for our health and living environment, but far from a given for everyone. According to the World Health Organization (WHO), there are currently over 2 billion people living with limited or no access to clean water.
This global challenge is at the center of the research at Chalmers University of Technology, Gothenburg/Sweden, which has developed a method to easily remove pollutants from water. The researchers have built up solid knowledge about cellulose nanocrystals – and this is where the key to water purification lies. Nanocrystals are nanoparticles in crystal form that are extremely small: a nanoparticle is between 1 and 100 nm in at least one dimension. These tiny nanoparticles have an outstanding adsorption capacity, which the researchers have now found a way to utilize.
With a unique holistic approach to these cellulose nanocrystals, examining their properties and potential applications, a bio-based material has now been created, a form of cellulose powder with very good purification properties that can be adapted and modified depending on the types of pollutants to be removed.
In a recently published study, the researchers show how toxic dyes can be filtered out of wastewater using the method and material developed by the group. The research was conducted in collaboration with the Malaviya National Institute of Technology, Jaipur/India, where dye pollutants in textile industry wastewater are a widespread problem.
The treatment requires neither pressure nor heat and uses sunlight to catalyze the process. As the contaminated water passes through the cellulose powder filter, the pollutants are absorbed and the sunlight entering the treatment system causes them to break down quickly and efficiently. It is a cost-effective and simple system to set up and use, and it could be of great benefit in countries that currently have poor or non-existent water treatment.
So far, laboratory tests with industrial water have shown that more than 80% of the dye pollutants are removed with the new method, and there are good opportunities to further increase the degree of purification.
There are also potentially opportunities to use cellulose nanocrystals for the treatment of other water pollutants than dyes. In a previous study, the research group has shown that pollutants of toxic hexavalent chromium, which is common in wastewater from mining, leather and metal industries, could be successfully removed with a similar type of cellulose-based material. The group is also exploring how the research area can contribute to the purification of antibiotic residues.