AgCeY分子筛吸附剂的制备及性能研究

以NaY分子筛为载体,通过液相离子交换法制备了经Ag、Ce双金属离子改性的AgCeY吸附剂,并利用UV-vis、XRD、BET、ICP、XPS和FT-IR技术对吸附剂进行了表征。以噻吩/苯并噻吩/正辛烷/甲苯体系为汽油模拟体系,考察了制备条件和吸附条件对吸附剂脱硫性能的影响以及吸附剂再生性能。结果表明,AgCeY吸附剂上Ag、Ce这两种金属元素分别以Ag⁺、Ce⁴⁺形式存在,AgCeY吸附剂具有类似于AgY的高的脱硫性能,又具有类似于CeY的高的吸附选择性,AgCeY对噻吩(TP)和苯并噻吩(BT)的吸附选择性顺序为BT > TP;最适宜的制备条件为先交换Ag后交换Ce离子、离子交换24 h、Ce/Ag物质的量比为2.5、500 ℃焙烧;在原料20 mL、AgCeY吸附剂用量0.2 g、吸附温度50 ℃、吸附时间60 min下,噻吩脱硫率可达到59.0%,苯并噻吩脱硫率达到96.5%。

Study on preparation and characteristics of AgCeY zeolites

Adsorbents were successfully prepared by the liquid-phase ion-exchange Y zeolites with Ag, Ce and combined Ag-Ce metal ions.The adsorbents were characterized by the X-ray diffraction (XRD), UV-vis diffuse reflectance (UV-vis), N₂-adsorption specific surface area measurements (BET), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectrum analysis (XPS) and Fourier transform infrared (FT-IR). With thiophene/benzothiophene/1-octane/toluene model oil as feedstock,the effect of preparation and adsorption conditions of AgCeY adsorbent on desulfurization and its recycling use performance were investigated. The results show that the Ag and Ce species which are loaded on AgCeY zeolite exist as Ag⁺ and Ce⁴⁺. AgCeY not only has the high sulfur adsorption capacity similar to AgY but also has the higher selectivity for sulfur compounds similar to CeY. And the adsorption affinity of AgCeY follows in the order: benzothiophene > thiophene. The AgCeY adsorbent exchanged the Ag⁺ first, then the Ce³⁺, with a Ce/Ag mole ratio of 2.5 for 24 h, at 500 ℃ exhibited the best performance. With oil 20 mL, AgCeY 0.2 g, at 50 ℃ adsorbed for 60 min, the TP and BT uptake reach 59.0% and 96.5%, respectively.