Experimental study of phenol removal from aqueous solution by adsorption onto synthesized Faujasite-type Y zeolite

This research aims to carry out an experimental study to remove toxic phenol from wastewater by Faujasite-type Y zeolite as adsorbent. The adsorbent was firstly synthetized and characterized by X-ray diffraction to determine both its mineralogical composition and the crystal structure of zeolite, differential thermal analysis-thermogravimetric analysis to understand its thermal behavior with respect to the sintering temperature, the N2 adsorption/desorption method to get the surface area measurements and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy to study the surface morphology. The operating conditions such as contact times, pH and temperature of adsorption were studied and optimized to improve efficiently the process of adsorption. The adsorption analysis showed an adsorption capacity of 83 mg/g towards phenol at optimum pH = 4 and 52°C. The reaction kinetics was studied by pseudo-first-order and pseudo-second-order models, and it was observed that the pseudo-second-order accurately described the adsorption kinetics. In addition, the Freundlich and Langmuir adsorption isotherms models were applied, the found results showed that the Langmuir adsorption isotherm model is the most appropriate to describe the adsorption of phenol on Faujasite zeolite. The thermodynamic results also confirm the reversibility and disorder of the process, indicating that the phenol adsorption was primarily physical, and the decisive effect of π–π interactions and H-bonds on the adsorption capacity could not be considered the main force. As well as, high silica zeolites have several acidic sites, and associated base sites, which could act as active adsorption sites for phenol, suggest that the zeolites have potential applications in the removal of organic pollutants from wastewater.