Enhanced CO₂ Adsorption over Silica-Supported Tetraethylenepentamine Sorbents Doped with Alkanolamines or Alcohols

Abstract

Silica-supported tetraethylenepentamine (TEPA/SiO 2 ) sorbents for CO 2 adsorption were prepared by incipient impregnation method, in which porous silica was loaded with TEPA and alkanolamines or alcohols as dopants. Both CO 2 adsorption capacity and amine utilization efficiency of these sorbents were evaluated in a self-assembled fixed-bed reactor. The results show that the introduction of alkanolamines or alcohols, especially those with higher amine and hydroxyl densities, into TEPA/SiO 2 notably improves their CO 2 adsorption performance. The maximum CO 2 adsorption capacity (4.14 mmol/g) was obtained over a doped TEPA/SiO 2 loaded with 30% TEPA and 30% diethanolamine. The interaction between hydroxyl and amino groups, leading to the improved dispersion of TEPA phase on the surface of SiO 2 , was investigated by N 2 adsorption−desorption measurements, scanning electron microscopy, and X-ray photoelectron spectroscopy. The calculation based on density functional theory shows that the existence of the hydroxyl group in the doped TEPA/SiO 2 sorbents increases the CO 2 adsorption energy, which is the key factor to achieve the optimized CO 2 adsorption capacity and amine utilization efficiency.

Role of additives in silica-supported polyethylenimine adsorbents for CO2 adsorption

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Microfluidic fabrication of novel polymeric core‐shell microcapsules for storage of CO2 solvents and organic chelating agents

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