CO₂ Capture by Amine-Functionalized Magnesium Oxide: Experimental and Modelling Studies

The concentration of carbon dioxide in the atmosphere has reached an alarming level. CO₂ can be captured using the traditional amine absorption process. However, this process is an energy-intensive and environmentally unfriendly. Thus, we have developed in this work a novel adsorbent using magnesium oxide (MgO) that has been functionalized with 3-aminopropyl-triethoxysilane (APTES). This CO₂ adsorbent (APTES-MgO) is reported for the first time in this work to the best of our knowledge. APTES-MgO can significantly adsorb CO₂ at ambient conditions. It is fully regenerable and the regeneration process can be carried out at mild conditions (120°C and atmospheric pressure) under a nitrogen environment. This low regeneration temperature indicates that the energy consumption of CO₂ capture process using APTES-MgO could be low. The adsorption capacity of APTES-MgO is more than 1.5 mmol/g at 30 °C and 1 atm. The regeneration process of APTES-MgO can fully restore its CO₂ adsorption capacity. The adsorption process has been modelled using a first order adsorption model. The mathematical model can track the experimental data quite well, allowing the estimation of the key adsorption parameters. The effectiveness of APTES-MgO in adsorbing CO₂ at ambient conditions and its regenerability and stability suggest its potential commercial application in CO₂ capture industry.