噻吩类硫化物在Ag(I)X分子筛上的选择性吸附

Selective Adsorption of Thiophenic Sulfur Compounds on Ag(I)X Adsorbent

以13X分子筛为载体,采用液相离子交换法制备了Ag(I)X吸附剂。以噻吩、3-甲基噻吩、2,5-二甲基噻吩为模拟汽油中的含硫化合物,采用固定床吸附装置考察Ag(I)X对模拟汽油中不同噻吩类硫化物的吸附容量及吸附选择性,以及甲苯和环己烯对吸附剂脱硫性能的影响,并对吸附机理进行了分析。结果表明,Ag(I)X吸附剂对模拟汽油中的噻吩类硫化物具有较高的吸附容量和吸附选择性,噻吩、3-甲基噻吩、2,5-二甲基噻吩的穿透硫容分别为0.776、0.859和0.926mg/g,吸附选择性由大到小的顺序为2,5-二甲基噻吩、3-甲基噻吩、噻吩。模拟汽油中甲苯和环己烯的存在,使Ag(I)X吸附剂的总穿透硫容分别降低了61%和34%,表明甲苯比环己烯有更强的竞争吸附作用。π配位机理能用来解释Ag(I)X对不同噻吩类硫化物的吸附性能差异,以及芳烃和烯烃的存在对其吸附噻吩类硫化物性能的影响。

Ag（Ⅰ）X adsorbent was prepared with 13X zeolite as the adsorbent carrier by the method of liquid phase ion exchange.Thiophene,3-methylthiophene and 2,5-dimethylthiophene were used as the sulfur-containing compounds in model gasoline sample to investigate the adsorptive capacity and selectivity of Ag（Ⅰ）X adsorbent for various sulfur compounds by the adsorption experiment in fixedbed,and the effects of toluene and cyclohexene on the adsorptive performance of Ag（Ⅰ）X were also investigated.The adsorption mechanism of thiophenic compounds on Ag（Ⅰ）X was analyzed.The results showed that Ag（Ⅰ）X had high adsorptive capacity and selectivity for thiophenie compounds.Breakthrough adsorption capacities of Ag （Ⅰ）X for thiophene,3-methylthiophene and 2,5-dimethylthiophene were 0.776,0.859 and 0.926 mg/g,respectively,which meant the selective adsorption order for them from big to small was 2,5-dimethylthiophene,3-methylthiophene and thiophene.The presence of toluene and cyclohexene in the model gasoline led to a reduction of total breakthrough adsorption capacity by 61％ and 34％,respectively,which indicated that the competitive adsorption of toluene to thiophenic compounds was stronger than that of cyclohexene.The π-complexation mechanism could be used to interpret the differences in adsorption performances of Ag（Ⅰ）X for different thiophenic compounds,as well as the competitive adsorption of toluene and cyclohexene to thiophenic compounds.