Mechanism and Kinetics of CO2 Adsorption on Surface Bonded Amines
Mechanism and Kinetics of CO2 Adsorption on Surface Bonded Amines
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DOI：
10.1021/jp512001t
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发表时间：
2015-02-26
影响因子：
3.7
通讯作者：
Lercher, Johannes A.
中科院分区：
文献类型：
--
作者：
Hahn, Maximilian W.;Steib, Matthias;Lercher, Johannes A.
研究了H2O对胺浸渍SBA-15吸附CO2的机理和动力学的影响。不含H2O的吸附机理主要通过形成稳定在两个胺基之间的氨基甲酸酯来进行。在水合吸附剂上形成碳酸氢盐和表面稳定的氨基甲酸盐。膜扩散的限制，没有观察到在高胺负载的CO2吸附。气态水降低了吸附速率，但增加了最大平衡吸收以及突破前的反应器床层的吸收。水膜在含有大于5体积%的气体流中的吸附剂颗粒上形成，气态H2O限制了CO2与活性胺位点的相互作用并约束了吸附速率。在H2O蒸气存在下的较高的CO2吸收是吸附机理的改变的结果，其增加胺效率，从而导致较高的吸附容量。在100 ℃的最高解吸温度下，所有吸附剂的吸附都是完全可逆的。
The impact of H2O on the mechanism and kinetics of CO2 adsorption by amine-impregnated SBA-15 has been investigated. The H2O-free adsorption mechanism proceeds predominantly via formation of carbamates stabilized between two amine groups. Bicarbonates and surface stabilized carbamates were formed on hydrated sorbents. Film diffusion limitations were not observed during adsorption of CO2 at high amine loadings. Gaseous water decreased the adsorption rate but increased the maximum equilibrium uptake as well as the uptake before breakthrough of the reactor bed. A water film is formed on the adsorbent particles in gas streams containing more than 5 vol %, gaseous H2O limiting the interaction of CO2 with the active amine sites and constraining the rates of adsorption. The higher uptake of CO2 in the presence of H2O vapor is a result of a change in the adsorption mechanism that increases the amine efficiency, thus leading to a higher adsorption capacity. The adsorption was fully reversible for all adsorbents at a maximum desorption temperature of 100 degrees C.