New method for removing toxic dyes from wastewater

An inexpensive and eco-friendly method for removing textile dyes from wastewater could make a big contribution towards combating a growing pollution problem for the textile industry worldwide. Amor Mosbah and colleagues at the University of Manouba in Tunisia describe their method in an article entitled “Peptides Fixing Industrial Textile Dyes: A New Biochemical Method in Wastewater Treatment,” published in the Hindawi Open Access title, Journal of Chemistry.

The toxicity of wastewater is “one of the most serious problems facing humanity,” the authors state. Synthetic and toxic dyes used in the textile industry are a large contributor to the problem, especially as most of the dyes used are not easily biodegradable. The resulting dangers from this increased toxicity of wastewater are particularly acute in regions where drinking water may be extracted downstream from textile manufacturing plants.

The researchers’ proposed solution is to synthesise a series of small molecules called peptides that can combine with dye molecules in order to reduce their toxicity and therefore the lower the overall toxicity of the water. Rather than being derived from natural proteins, these dye-fixing peptides are designed and synthesised from their simpler starting materials – amino acids. This increases the binding properties, meaning that it is a more efficient removal method that allows for reuse of the water, dyes and synthesised peptides.

In their initial proof-of-concept work, the research team made two peptides, each containing ten linked amino acids, and tested their ability to bind to the common textile dye ‘Cibacron blue’. The peptides, which were themselves bound to a stationary support material, were able to capture almost all of the dye in the solution used to mimic the flow of wastewater through a treatment facility. One of the peptides retained over 90% of the Cibacron blue while the other peptide captured almost 46% of the remaining dye. Thus, in combination, the peptides offer a highly effective wastewater treatment procedure.

The researchers now hope to build on these promising initial results to develop a simple and quick dye-removal system that could be easily applied on an industrial scale to improve the quality of wastewater and reduce toxicity.