Gatti G, Vittoni C, Costenaro D, Paul G, Mangano E, Brandani S, Marchese L, Bisio C
Dipartimento di Scienze e Innovazione Tecnologica and "Centro interdisciplinare Nano-SiSTeMI", Università del Piemonte Orientale, via T. Michel 11, 15121, Alessandria, Italy.
Phys Chem Chem Phys. 2017 Nov 8;19(43):29449-29460. doi: 10.1039/c7cp05177h.
The CO adsorption properties of hybrid organic-inorganic MCM-41 silicas with different particle sizes are described here. Micrometric to nanometric MCM-41 silicas are functionalized by introducing amino groups via grafting of 3-[2-(2-aminoethyl)aminoethyl]aminopropyltrimethoxysilane (PAPTS). A combination of FTIR and SS-NMR spectroscopies is adopted to distinguish between physisorbed and chemisorbed CO. A higher amount of CO is physisorbed in the nanometric sample because of a higher pore volume, whereas chemisorbed (carbamate and acid carbamic) species are more abundant in the micrometric sample. The adsorption process is also quantitatively studied using three different techniques (i.e. volumetric measurements, Thermo-Gravimetric Analysis (TGA) and Zero Length Column (ZLC) analysis), especially focusing on the reversibility of the reactions between CO and amino groups. The three techniques show a higher CO adsorption capacity for MCM-41 with nanometric size compared to the micrometric one. Finally, the process is studied at different temperatures (i.e. from 35 to 90 °C) in order to find the best operating conditions.
本文描述了不同粒径的有机-无机杂化MCM-41硅胶对CO的吸附特性。通过接枝3-[2-(2-氨基乙基)氨基乙基]氨基丙基三甲氧基硅烷（PAPTS）引入氨基，对微米级到纳米级的MCM-41硅胶进行功能化处理。采用傅里叶变换红外光谱（FTIR）和固体核磁共振光谱（SS-NMR）相结合的方法来区分物理吸附和化学吸附的CO。由于纳米级样品的孔体积较大，其物理吸附的CO量更高，而微米级样品中化学吸附（氨基甲酸盐和氨基甲酸）的物种更为丰富。还使用三种不同技术（即容量测量、热重分析（TGA）和零长度柱（ZLC）分析）对吸附过程进行了定量研究，特别关注CO与氨基之间反应的可逆性。与微米级MCM-41相比，这三种技术显示出纳米级MCM-41对CO具有更高的吸附容量。最后，在不同温度（即35至90°C）下对该过程进行了研究，以找到最佳操作条件。
