Removing textile dyes from water with wood-based powder

Researchers have developed a cellulose powder that could remove a large proportion of dye and heavy metal contamination from waterways

Spotted: The fashion industry contributes a huge amount of pollutants to the world’s water. According to some sources, textile dyeing and finishing are responsible for around 20 percent of global water pollution. This is partly because of weak regulation and enforcement in producer countries like Bangladesh, where wastewater is often dumped directly into rivers and streams. Stronger regulations would help, but new methods for clean-up will also be needed. This is what a research team at Sweden’s Chalmers University of Technology is focused on.

The researchers, led by Gunnar Westman, Associate Professor of Organic Chemistry, have developed a new method for purifying contaminated water using cellulose-based nano-crystals. As contaminated water passes through the material, the pollutants are absorbed. Sunlight then causes the pollutants to quickly break down.

The cellulose crystals can also be adapted and modified to remove a wide variety of pollutants in addition to dyes. In an earlier study, the group demonstrated that toxic hexavalent chromium, which is commonly given off by the mining, leather, and metal industries, could also be removed with a similar process. The group is also exploring the use of cellulose in purifying water contaminated with antibiotic residues.

Laboratory tests of the material have shown that it removes more than 80 per cent of dye pollutants. Westman comments that “Going from discharging completely untreated water to removing 80 percent of the pollutants is a huge improvement, and means significantly less destruction of nature and harm to humans. In addition, by optimising the pH and treatment time, we see an opportunity to further improve the process so that we can produce both irrigation and drinking water.”

Springwise has covered a number of recent developments in water treatment, including a portable sewage treatment system and a versatile membrane technology that offers a cheaper way to filter water.

Written By: Lisa Magloff