Adsorptive Removal of Aromatic Compounds Present in Wastewater by Using Dealuminated Faujasite Zeolite

The adsorption of aromatic compounds (nitrophenols, nitroaniline, chlorophenols, chloroanilines) present in wastewater using dealuminated faujasite zeolite has been investigated. The adsorption capacity of faujasite zeolite depends on the pH, (the neutral form of the pollutants is more easily adsorbed into zeolite than the dissociated form), and on the solubility in water of the aromatic compounds. The adsorption capacity for a family of compounds increases with decreasing water solubility. In this study, we have shown that the pollutant acidic character enhances their adsorption into the zeolite. Thus, the changeover of phenol to aniline decreases the adsorbent-adsorbate interaction, as well as in the substitution of the NO2 group by a Cl group. The adsorption data was analyzed using the Fowler-Guggenheim isotherm. The sorption mechanism of nitrophenol in faujasite zeolite was investigated using Raman spectroscopy and through a thermodesorption kinetic study. The relative affinity of the phenolic compounds toward the surface of the dealuminated faujasite was related to the electron donor-acceptor complex formed between the basic sites on the zeolite (oxygen) and the hydrogens (acidic site) of the aromatic ring and of the phenols and anilines functions.