超枝化固体胺吸附分离烟气中二氧化碳

Adsorption separation of CO_2 from flue gas by hyperbranched solid-amine

采用浸渍方法将四乙烯五胺(TEPA)负载到KIT-6介孔硅材料孔道表面上合成超枝化固体胺KIT-6(TEPA),并对其吸附CO2性能进行研究。结果表明,随着温度的升高,KIT-6(TEPA)的CO2吸附量呈增长趋势,343 K时获得最大吸附量(3.1 mmol.g-1)。继续升高温度吸附量则呈下降趋势。KIT-6(TEPA)吸附CO2过程以化学吸附为主,化学吸附量占总吸附量的97.2%以上(323～343 K)。气体中水的存在对吸附过程起着积极作用。气体含水量为12%时,CO2吸附容量达到最大值(3.5 mmol.g-1)。吸附/再生实验表明KIT-6(TEPA)具有稳定的吸附性能,20次循环实验后,CO2的吸附容量基本保持不变。最后,使用失活模型模拟了KIT-6(TEPA)吸附CO2的吸附穿透曲线,模拟相关系数均大于0.99。

Hyperbranched solid amine was prepared with KIT-6 type mesoporous silica,which was modified by tetraethylenepentamine（TEPA）using post-synthetic impregnation.The adsorption behavior of CO2 on KIT-6（TEPA）was investigated using an adsorption column.The adsorption capacity of KIT-6（TEPA）for CO2 increased with temperature at 303—343 K,but decreased as temperature increased at 343—353 K.The maximum adsorption capacity is 3.1 mmol g-1 at 343 K.The mechanism of CO2 adsorption on KIT-6（TEPA）is mainly chemical adsorption.The adsorption capacity is improved by moisture.It reaches 3.5 mmol·g-1 in the presence of 12% water.The adsorption capacity is maintained after 20 cycles of adsorption and regeneration,indicating that the KIT-6（TEPA）is stable in a prolonged cyclic operation.Experimental breakthrough curves are fitted with a deactivation model,giving good agreement with experimental data.