GRAPHENE VS. ACTIVATED CARBONS IN LIQUID-PHASE ADSORPTION: ANY FUNDAMENTAL IMPROVEMENTS?

摘要

Since graphene became an exciting new addition to the wide range of carbon materials, there has been an explosion of research devoted to its virtues as an adsorbent. Its intrinsically high and easily accessible surface area should offer the potential for significant improvements over conventional adsorbents such as activated carbons or high-surface-area graphite. From a fundamental point of view, however, the well known thermodynamic and kinetic factors that govern the uptake of solutes, especially from aqueous solution, are presumably the same, and yet they are not invoked frequently enough. In this study, we analyze the similarities and differences in the reported behavior of these liquid-phase adsorbents. In particular, we perform an arguably critical quantum chemistry analysis of the electronic and geometric effects of graphene’s surface functional groups on its electron density distribution. The impact on the adsorption affinity of the edge atoms is then analyzed and compared with representative experimental results.