Fe掺杂改性HMS分子筛的制备及其吸附脱硫性能

Synthesis of Fe doped modified HMS molecular sieve and its adsorption desulfurization performance

以正硅酸乙酯(TEOS)为硅源、硝酸铁为铁源、十二胺(DDA)为模板剂,利用溶胶-凝胶法制备金属Fe掺杂改性Fe-HMS分子筛,通过XRD、N2吸附-脱附、FT-IR、TPD技术表征制得Fe-HMS,结果表明制得Fe-HMS为介孔分子筛,掺杂Fe进入HMS分子筛骨架,导致比表面积及孔容减小,分子筛表面酸性增强。利用制得Fe-HMS对含噻吩及其衍生物的模拟燃油进行间歇静态及连续动态吸附实验,得到FeHMS分子筛最佳制备条件为n(Fe)∶n(Si)=1∶50,n(DDA)∶n(TEOS)=1∶5,焙烧脱模温度550℃;噻吩及苯并噻吩在Fe-HMS分子筛上的吸附过程可以利用一阶、二阶动力学模型很好的描述,吸附过程包括物理吸附及化学吸附;Fe-HMS分子筛对不同噻吩类含硫化合物的穿透吸附硫容大小顺序为:噻吩(T)<3-甲基噻吩(3-MT)<2,5-二甲基噻吩(2,5-DMT)<苯并噻吩(BT)。

Metal Fe doped modified Fe-HMS molecular sieve was synthesized by sol-gel method,using tetraethyl orthosilicate(TEOS)as silicon source,ferric nitrate as iron source and dodecyl amine(DDA)as template.The Fe-HMS molecular sieve was characterized by X-ray diffraction,N2adsorption-desorption,Fourier transform infrared spectroscopy and NH3 temperature programmed desorption technology.The results showed that the FeHMS was mesoporous molecular sieve,and Fe doped into HMS zeolite frameworks resulting in specific surface area and pore volume decreased,but the material's surface acidity increased.The adsorptive desulfurization performance of modified Fe-HMS was evaluated by model fuel(MF)containing thiophene and its derivatives through static and dynamic adsorption.The optimum synthesis conditions of Fe-HMS were under the mole ratio n(Fe)∶n(Si)=1∶50,the mole ratio n(DDA)∶n(TEOS)=1∶5,and the calcination temperature for template removing was 550 ℃.Thiophene and benzothiophene adsorbed on Fe-HMS can be well described by first order and second order kinetic model,which illustrated the adsorption process including both physical and chemical adsorption.Fe-HMS adsorbed different thiophene structure sulfur compounds through the adsorption capacity order:thiophene<3-methyl thiophene<2,5-dimethylthiophene<benzothiophene.