Thermodynamics and kinetics studies on adsorption of benzothiophene onto Ag/TiO2-NaY zeolite

The TiO2-NaY complex support was prepared by the sol-gel method and the Ag/TiO2-NaY adsorbent prepared by the impregnation method. The adsorbents were characterized by X-ray diffraction (XRD), N2-adsorption specific surface area measurements (BET) and scanning electron microscope (SEM). The influence of several variables such as contact time, mass of adsorbent and initial concentration of sulfur on the adsorption were investigated. The isotherms and kinetics of benzothiophene (BT) adsorption from petroleumether onto Ag/TiO2-NaY were studied, and the thermodynamic parameters(ΔG, ΔH, ΔS) for the adsorption of BT were calculated. The results show that anatase TiO2 is the main phase over AgTY adsorbent and the Y-zeolite framework of TiO2-NaY zeolite is retained unchanged compared with NaY. With adsorption temperature of 50°C, adsorption time of 180 min and adsorbent/oil ratio of 0.01 g/mL, the equilibrium adsorption capacity is 1.346%. Compared with Freundlich equation, the Langmuir model can well describe the adsorption isotherms of BT onto Ag/TiO2-NaY, and the kinetics for the adsorption process can be described by pseudo-second-order model.