Researches from University of Washington develop a sponge-like material capable of isolating harmful dyes in lakes and rivers.
Dyes offer wide variety of applications in industries such as textiles, cosmetics, food processing, papermaking and plastics and is primarily use to color clothing, eye shadow, toys and vending machine candy, and others. However, around a tenth of all dye products are discharged into the waste stream during manufacturing process, which escape in conventional wastewater-treatment processes. These dyes remain in the environment with its presence in lakes, rivers and holding ponds that leads to contamination of water.
Now a research led by University of Washington created a sponge-like material capable of removing color from dyes in water. The environmentally friendly method was described in a paper published online in the journal Applied Catalysis B: Environmental on June 6, 2018. The sponge-like material was created from wood pulp and small bits. Cellulose found abundantly in plant cell walls is the backbone of the material. The other component in the material is tiny pieces of palladium that serve as a catalyst to help remove color quickly.
The change in color of the dyes facilitates a visible spectrum that can allow sunlight to enter easily in water and facilitate photosynthesis that allows plants to grow normally again. Moreover, the dye structure and its color could be altered by the chemical reduction of dyes using molecules called reducing agents. However, the reaction takes weeks to occur and is not very efficient. The new sponge-like material contains a catalyst that operates with the reducing agent to speed this process up to almost instantaneous. Combination of cellulose molecules with palladium metal is heated and mixed in a blender. The solution is purified and freeze-dried to form a porous and reusable material identical to a sponge. The material 99 percent air and its large pores allow water to flow in and out as the metal catalyst particles within the material work to remove any color present. Moreover, like a sponge, the material can be squeezed of its water and reused multiple times without losing the ability to remove color from water.