Simultaneous adsorption of phenol and chromium(VI) from binary mixtures onto powdered activated carbon

The ability of powdered activated carbon to adsorb phenol and chromium(VI) ions, both singly and in combination, was investigated in a batch system. The effects of initial pH and single- and dual-component concentrations on the equilibrium uptakes were investigated. The optimum initial adsorption pH for both chromium(VI) ions and phenol was determined as 1.0. Multi-component adsorption studies were performed at this initial pH value. It was observed that the equilibrium uptakes of phenol and chromium(VI) ions were changed due to the presence of other component. Adsorption isotherms were developed for both single- and dual-component systems at pH 1.0, and expressed by the mono- and multi-component Langmuir, Freundlich and Redlich-Peterson adsorption models and model parameters were estimated by the non-linear regression method in the studied concentration ranges. The non-competitive Freundlich model were well fitted to the mono-component adsorption equilibrium data for both phenol and chromium(VI) ions while the competitive, modified Freundlich model showed good prediction in the competitive adsorption of phenol and chromium(VI) ions on the adsorbent. The results suggested that powdered activated carbon may find promising applications for simultaneous removal and separation of phenol and chromium(VI) ions from aqueous effluents.