Adsorption of Rhodamine 6G from aqueous solutions on activated carbon

The effects of particle size (0.5-1.0 mm), temperature (30-60 degrees C), and solution pH (7-9) on the adsorption equilibrium of dye Rhodamine 6G by activated carbon were studied in batch modes. The isotherm data could be well described by the Langmuir equation. Under the ranges tested, a maximum adsorption capacity of 44.7 mg/g was obtained. Batch kinetic parameters such as the Lagergren's rate constant and intraparticle diffusion coefficient of adsorption were determined. It has been shown that the intraparticle diffusion of dye molecules within the adsorbents was identified as the rate-limiting step in the present adsorption process.