Ag／TiO2-NaY吸附苯并噻吩热力学和动力学研究

Thermodynamics and kinetics studies on adsorption of benzothiophene onto Ag/TiO_2-NaY zeolite

以溶胶-凝胶法制备的TiO2-NaY分子筛为载体,采用浸渍法制备Ag/TiO2-NaY吸附剂,并用X射线衍射(XRD)、N2吸附脱附(BET)、扫描电镜(SEM)等技术对吸附剂进行表征。考察吸附时间、吸附剂质量、硫初始质量浓度等吸附条件对吸附剂吸附性能的影响,研究Ag/TiO2-NaY吸附苯并噻吩吸附等温线和吸附动力学,计算其热力学参数。结果表明:Ag/TiO2-NaY吸附剂中TiO2主要以锐钛矿型存在,与NaY相比,TiO2-NaY分子筛的骨架结构并未发生明显的改变;在吸附温度50℃、吸附时间180 min、剂油比为0.01 g/mL时AgTY吸附剂的平衡吸附量为1.346%;与Freundlich方程相比,Langmuir方程能更好地反映Ag/TiO2-NaY对苯并噻吩的等温吸附线,拟二级动力学方程能很好地描述苯并噻吩在Ag/TiO2-NaY上的吸附过程。

The TiO2-NAY complex support was prepared by the sol-gel method and the Ag/TiOz-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（ AG, AH, AS） 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 Fe℃ , adsorption time of 180 rain 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.