Reportedly, Azo dyes with methyl, methoxy, sulpho or nitro groups are difficult to degrade.

Azo based and Sulphur based dyes basically difficult to degrade during treatment processing.

In my research I have found that azo dyes with methyl, sulfo and nitro groups are difficult to degrade. We have tried to degrade them applying nanoparticles but degradation efficiency is not good.

Luis Cumbal

azo dyes are hard to eliminate from water because these dyes or their metabolites have carcinogenic, teratogenic and mutagenic effects on humans and other life forms.

Azo dyes are very hard to remove from textile effluent even if u try using several techniques