Researchers have used bottom ash and deoiled soya, two waste materials to remove Congo red, a toxic dye and possible carcinogen from waste water1.
Besides being an irritant, Congo red may cause paternal effects or fetal abnormalities and is harmful if swallowed, inhaled or absorbed through skin. To remove it from waste waters, the researchers chose bottom ash, a power plant waste material, and deoiled soya, an agricultural waste.
The researchers found that bottom ash adsorbed 96.95% and deoiled soya adsorbed more than 97% of Congo red. Further study revealed that regeneration of the dye was possible by treating the ash and soya with sodium hydroxide solution. About 90% of the dye was recovered in both cases, the researchers say.
