TEPA/TETA改性SBA-15对CO_2吸附性能的影响

Effects of TEPA/TETA-modified SBA-15 on CO_2 adsorption properties

以非离子表面活性剂P123作为模板剂,正硅酸乙酯为硅源,加入扩孔剂合成SBA-15介孔材料。以三乙烯四胺（TETA）和四乙烯五胺（TEPA）作为改性剂,对所得材料分别进行质量百分比20%、30%、35%和40%的负载量改性,得到CO2的吸附材料。用热重法测定材料的CO2吸附脱附性能,氮气物理吸附-脱附和元素分析法对样品进行表征。结果表明,同样负载条件下,TEPA改性效果显著优于TETA改性,这是由于TEPA比TETA多出一个胺基;在4个附载量中,30%-35%的负载量最优,其中35%TEPA负载量的扩孔SBA-15（SBA-15k）的CO2吸附量最高,达2.86 mmol/g;循环吸附脱附的结果表明经过5次吸附脱附,材料的吸附性能没有明显变化;吸附平衡时间很短,不到10 min,有利于实际应用;氮气物理吸附-脱附和元素分析结果表明,改性剂很好地负载到SBA-15k样品上,SBA-15k对TEPA和TETA的负载改性起到促进作用。

Mesoporous silica SBA-15 were synthesized using tri-block copolymer P123 as a structure-directing agent,tetraethoxysilane as the silicon source,and toluene as swelling agents. Novel CO2 adsorbents for CO2 removal were prepared by introducing 20%,30%,35% and 40% loadings of TETA and TEPA into SBA-15 using a post-synthetic impregnation method. The adsorption/desorption capacities were determined by thermal gravimetric analysis method（ TGA）. The properties of the mesoporous materials after surface modification were characterized by N2adsorption-desorption and elemental analysis（ EA）. The results clearly indicated that when the loadings of TEPA/TETA were the same,the samples modified by TEPA were superior to the samples modified by TETA due to the one more amino group in the molecule of TEPA than that in TETA. The results also indicated that the samples with the loadings arranged in 30% - 35% had the best adsorption capacities in the four loadings; the adsorption activity of SBA-15 k modified by TEPA with 35% showed the maximum capacity and it was 2. 86 mmol/g. The CO2 adsorption capacity after five adsorption/desorption recycles showed no obvious change and the short equilibrium durations（ ≤10 min） were good for the practical application. The results of N2 adsorption/desorption and elemental analysis showed that the modification agents were introduced into the samples and the SBA-15 k was good for the modification of TEPA and TETA.