Removal of methyl orange and mythelene blue dyes from aqueous solution using low cost adsorbent zeolite synthesized from fly ash.

The zeolite ZX1 synthesized from fly ash was employed as effective adsorbent for removal of methylene blue and methyl orange, from its aqueous solution. In the present study, X-type and A-type zeolite were synthesized by alkali fusion, followed by hydrothermal treatment. The synthesized zeolite was then characterized using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM). Solution pH has an important role in the the adsorption behavior of ZX1. Higher solution pH results in higher adsorption capacity. The equilibrium results were well described by Freundlich isotherm model. Physical regeneration at high temperature showed that the adsorbent exhibits somehow lower adsorption capacity as compared to the fresh sample. The values of changes in enthalpy (deltaH(o)) and entropy (deltaS(o)) during the adsorption process were found to be -20.85 kJ/mol and -90.61 J/mol K(-1). Adsorption of methyl orange over Zeolite ZX1 is much higher than ZA1. Correlation coefficient was found to be 0.998.