TiO_2-MCM-41的制备表征及选择性吸附脱硫研究

Preparation and Characterization of TiO_2-MCM-41 and Its Performance on the Desulfurization

以钛酸正丁酯作为钛源,MCM-41为载体,采用加热回流法合成了TiO2-MCM-41介孔分子筛(n(Si)/n(Ti)=5),并借助XRD、FT-IR、N2吸附-脱附等表征手段研究了吸附剂的结构特性。以催化裂化汽油为油品进行静态脱硫和动态脱硫实验,结合使用固定床技术和色谱-硫化学发光检测(GC-SCD)偶联技术系统考查了吸附剂的选择性吸附脱硫性能及其对不同硫化物的选择性规律。结果表明,TiO2在介孔分子筛MCM-41的内孔壁能均匀分散;TiO2与MCM-41孔道表面的SiO2以Si—O—Ti键连接;MCM-41经负载TiO2后,吸附脱硫性能明显提高;TiO2-MCM-41对FCC汽油中各种硫化物的选择性顺序为:四氢噻吩>2-甲基四氢噻吩≈C5硫醚>3,4-二甲基噻吩>2/3-乙基噻吩>2-乙基-5-甲基噻吩>噻吩>2,5-二甲基噻吩>C1-C3硫醇>2-甲基噻吩>2,3-二甲基噻吩>3-甲基噻吩>2,4-二甲基噻吩>苯并噻吩。

TiO 2-MCM-41 mesoporous molecular sieve（n （Si）/n （Ti）= 5 ）was synthesized by heating reflux method,using titanium tetrabutoxide as the Ti source,MCM-41 as the carrier.The samples were investigated by means of XRD,FT-IR and N2 adsorption/desorption.The static and dynamic desulfurization experiment was carried out using fluid catalytic cracking （FCC）fuel oils.Properties of selective adsorptive desulfurization of FCC gasoline on the adsorbents have been investigated in this paper by a fixed-bed adsorption experiment and a GC-SCD technique.It was indicated thatthe titania homodisperses in the modified MCM-41,titania connected with the pendant OH groups of MCM-41 via Si—O—Ti bonds.After the load of TiO 2 ,the properties of adsorptive desulfurization on the adsorbents weresignificantly improved.The removal selectivities of the sulfur compounds in the gasoline changed slightly before and after the load of TiO 2 ,while the poor removal selectivities of benzothiophene,2/3-methylthiophene,2,3-dimethylthiophene,2,4-dimethylthiophene and 2,5-dimethylthiophene on MCM-41 and TiO 2-MCM-41 were the same.