Effect of combined primary and secondary amine loadings on the adsorption mechanism of CO2 and CH4 in biogas

Biomethane, produced by biogas upgrading, is a promising energy source that can play key role towards net-zero emissions targets. The incorporation of amine functionalities into adsorbents for upgrading facilitate the selective adsorption CO2, but their effect has not been comprehensively studied within context CH4 mixtures. In this work, effectiveness in selectively separating CO2 from biogas, investigated. Primary, diamine, and triamine organo-silanes grafted at various loadings on SBA-15 were used to study mechanisms, associated with CO2:CH4 gas successful amines was confirmed thermogravimetric analysis, Fourier Transform Infrared, elemental analysis. different reagents resulted an alteration mechanism provided information developing relationship between capacity, selectivity, efficiency. Diamine loading 2.5 mmol/g moderate silane coverage 1.54 molecules/nm2 found provide best balance enhanced capacity (1.12 mmol/g), superior selectivity densely primary amines, lowest isosteric heat ~ 25 kJ/mol 1.12 compared 41 materials. Amongst all samples, lower bare adsorbent while minimising duty regeneration. Moreover, under isothermal desorption conditions °C, some samples achieved working capacities comparable higher loaded