Removal of azo dyes from aqueous solutions using activated carbon as an adsorbent.

The potentiality of commercially available activated carbon has been investigated as an effective adsorbent to remove the dyes from aqueous solutions. The effects of pH of the solution, adsorbent dose, solute concentration and temperature on activated carbon for azo dyes such as acid orange 7 and direct red 31 have been evaluated. The percentage removal of the dyes has been found to be high at neutral pH. The dynamics of adsorption has been studied at different temperatures. The adsorption data follow Langmuir model as well as Freundlich model in the case of acid orange 7 whereas the data for direct red 31 fit into only Langmuir model.