Abstract

MUNOZ-MUNOZ, Alexander et al. Nanoadsorbents to capture carbon dioxide (CO₂): an approach to biogas purification. Rev. ion [online]. 2020, vol.33, n.1, pp.57-66.  Epub June 26, 2020. ISSN 0120-100X.  https://doi.org/10.18273/revion.v33n1-2020006.

In recent years, the production of biogas in domestic biodigesters has been growing, being used in rural areas mainly for lighting and heating. Nevertheless, the presence of CO2 considerably reduces the calorific value of biogas, generating a decrease in thermal efficiency which makes it necessary to remove this component to improve the quality of the gas and increase its possibilities of application as fuel. In this research, the CO2 adsorption capacity of Aerosil 380 commercialized pyrogenic silica nanoparticles with amines was evaluated. Silica nanoparticles were prepared by the sol-gel method using tetraethyl orthosilicate (TEOS) as a precursor to silicon oxide or silica. The materials were functionalized by wet impregnation with 15 and 30 %w of diethanolamine and ethylenediamine. The characterization tests allowed us to determine the nanoparticle size (TEM), surface area (BET), thermal stability (TGA) and chemical composition (FTIR) of the nanostructures and to relate these properties to the affinity for adsorbate. The CO2 adsorption tests were carried out at a temperature of 30 °C under a flow of 60 mLmin-1 of CO2 at a pressure of 20 psi. Pyrogenic Aerosil 380 based silica materials obtained a higher adsorption capacity compared to synthesized silica nanoparticles, obtaining the highest adsorption capacity (35.4 mg g-1) for the 30 %w impregnated sample of diethanolamine, which can also adsorb CO2 in the presence of H2O.

Keywords : Silica Nanoparticles; CO₂ Adsorption; Biogas Purification..

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