|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|63729||48249||2016||9 صفحه PDF||سفارش دهید||دانلود رایگان|
Macroscopic SiO2 spheres with a homogeneous amine distribution were synthesized by a one-step emulsion based synthesis approach in a flow column reactor. The CO2 adsorption capacity of the nano-structured amine-functionalized silica spheres was studied in absence and presence of H2O. The structural properties were adjusted by varying solvents and surfactants during the synthesis and, at constant amine loadings, were found to be the main factor for influencing the CO2 sorption capacities. Under water-free conditions CO2 is bound to the amino groups via the formation of carbamates, which require two neighboring amino groups to adsorb one CO2 molecule. At constant amine concentrations sorbents with lower surface area allow to establish a higher amine density on the surface, which enhances the CO2 uptake capacities under dry conditions. In presence of H2O the CO2 adsorption changes to 1:1 stoichiometry due to stabilization of carbamates by protonation of H2O and formation of further species such as bicarbonates, which should in principle double the adsorption capacities. Low concentrations of physisorbed H2O (0.3 mmol/g) did not impair the adsorption capacity of the adsorbents for CO2, while at higher water uptakes (0.6 and 1.1 mmol/g) the CO2 uptake is reduced, which could be attributed to capillary condensation of H2O or formation of bulky reaction products blocking inner pores and access to active sites.
Hierarchically structured adsorbents with tunable physicochemical properties are evaluated for CO2 capture. Figure optionsDownload as PowerPoint slide
Journal: Journal of Energy Chemistry - Volume 25, Issue 2, March 2016, Pages 327–335