Impact of Surface Functional Groups and Their Introduction Methods on the Mechanisms of CO2 Adsorption on Porous Carbonaceous Adsorbents

The utilisation of solid adsorbents for the selective removal of CO2 from major emission points is an attractive method for post-combustion carbon capture due to the inherent potential for retrofit and cost-effectiveness. Although focus in the scientific community is often centred on extremely novel, high-performance and costly material development, the exploitation of carbonaceous adsorbents is another avenue of research proving to be extremely promising. This is even more pronounced when considering the abundance of carbon in various waste streams. The production of carbonaceous adsorbents, however, often requires significant post-treatments to enhance both the textural and physico-chemical properties of the adsorbent, as such, the incorporation of surface functionalities is unavoidable and can often lead to significant improvements to the associated CO2 adsorption. This review aims to critically assess the various routes for surface modification of carbonaceous adsorbents and the implications these may have on the incorporation of surface functional groups. Subsequently, the adsorption mechanisms for CO2 on surface-modified porous carbons are discussed in depth with consideration to the influence of the introduced functionalities. The review concludes with a detailed section on current modelling approaches such as the application of artificial intelligence, Monte Carlo, and Density Functional Theory simulations in this realm of research.