Decolorization of mixture of dyes: A critical review

Water plays a vital and essential role in our ecosystem. This natural resource is becoming scarce, making its availability a major social and economic concern. Use of a large variety of synthetic dyes in textile industries has raised an hazardous environmental alert. About 17 - 20% of freshwater pollution is caused by textile effluents. These effluents are recalcitrant to biodegradation and cause acute toxicity to the receiving water bodies, as these comprised of various types of toxic dyes, which are difficult to remove. Decolorisation of textile wastewater is therefore important before releasing it into the nearby local waterways. It therefore becomes essential to degrade the toxic chemicals of textile wastewater, so as to avoid the hazardous environmental effects. Several treatment methods have been employed to embark upon the problem of dye removal but degradation becomes further more difficult for effluents containing dye matrix.  The review study has been an attempt to present the different diversified attempts used for decolorisation of a mixture of dyes.