NiY分子筛选择性吸附脱硫性能及作用机理

用液相离子交换法制备了NiY分子筛，并用XRD、TEM、ICP、N2吸附和吡啶吸附原位红外技术等表征手段对其进行了表征. 利用固定床、气相色谱-硫发光检测器（GC-SCD）及傅里叶红外光谱（FT-IR）等方法系统研究了NiY分子筛对噻吩、2-甲基噻吩、3-甲基噻吩、四氢噻吩、苯并噻吩、二苯并噻吩、4-甲基二苯并噻吩、4，6-二甲基二苯并噻吩8种有机硫化物的选择性吸附脱硫性能和吸附机理. 结果表明，NiY分子筛对硫化物的穿透吸附硫容量顺序为四氢噻吩﹥苯并噻吩≈二苯并噻吩≈4,6-二甲基二苯并噻吩﹥4-甲基二苯并噻吩﹥2-甲基噻吩≈3-甲基噻吩﹥噻吩，说明有机硫化物的空间位阻效应不是其在NiY分子筛上吸附的决定因素. 红外结果表明，不同硫化物与NiY分子筛的作用机理并不相同，但主要以硫原子与金属离子配位作用（S-M作用）为主. 噻吩及其烷基取代物在NiY吸附剂上表面酸性作用下发生催化反应，噻吩环的共轭体系遭到破坏形成硫化物大分子或聚合物，导致分子筛孔道的堵塞，严重影响吸附剂的吸附脱硫能力. NiY的选择性吸附脱硫性能是硫化物与吸附中心的作用模式及吸附剂表面酸性综合作用的结果.

Selective Adsorption Desulfurization Performance and Adsorptive Mechanisms of NiY Zeolites

NiY zeolites were prepared by liquid phase ion exchange method and the adsorbents were characterized by XRD, TEM, ICP, Nitrogen adsorption and Py-IR. The adsorptive behavior of thiophene (T), 2-methylthiophene(2-MT), 3-methylthiophene(3-MT), tetrahydrothiophene(THT), benzothiophene(BT), dibenzothiophene(DBT), 4-methyldibenzothiophene(4-MDBT) and 4,6-dimethyldiben-zothiophene (4,6-D MDBT) on NiY zeolites were investigated by fixed bed, the latest generation of SCD detectors(GC-SCD) and Fourier Transform Infrared (FT-IR). The results show the breakthrough adsorption capacity of different sulfur compounds, and the order is: THT > BT ≈ DBT ≈ 4,6-DMDBT > 4-MDBT > 3-MT ≈ 2-MT > T，which indicates that the steric hindrance of sulfur compounds is not the crucial factor for their adsorptive properties on NiY zeolites. The mechanisms of thiophene and thiophene derivatives interacting with NiY zeolites were different, but the direct S-M interaction is the domain process. Thiophene and thiophene alkyl complex adsorbed on the surface acidity can subsequently undergo the opening of the heterocyclic rings, and the polymer molecules will plug the pore of zeolite, resulting in decreasing of the desulfurization capacity of NiY. Adsorption mechanisms and surface acidity of NiY zeolites are the key factors for the selective adsorption desulfurization.