Adsorption decolorization of phenolphthalein indicator in aqueous media using natural clay and the activated carbono

Natural clay and activated carbon are extremely encouraging for the removal of colored indicators in an aqueous solution. The natural clay and activated carbon were analyzed by X-ray diffraction (XRD) and Fourier transformation (FTIR) and the colored indicator was characterized by UV-Visible. The effects of various experiments, such as initial phenolphthalein concentration, contact time, temperature, pH and decolorization were studied. Dye removal increases with the decrease in the initial concentration of phenolphthalein and the contact time of the solution. The phenolphthalein removal percentage increases accordingly, reaching 99% for activated carbon and 98% for natural clay. The Langmuir and Freundlich adsorption models were used for descriptions of the adsorption equilibrium. The data was very well corrected with these models. Monolayer adsorption capacities were equal to 35 mgg-1 at pH 8.0 and temperature 27°C. Adsorption Measurements show that the adsorption process is very rapid and physical in nature. The results explain that the adsorption process is an exothermic and spontaneous physisorption.