Defect engineering the highly stable metal-organic framework, UiO-66, has been a popular research topic over the past several years. Since the surge in research on this subject, little attention has been given to the implications for the ion-doping mechanism and, ultimately, potential methods for functionalizing UiO-66. The research group proposes post-synthetic procedures for ion-doping mechanisms. The UiO-66 sample was doped with cations and characterized using various techniques. The selective adsorption of CO2/N2 and O2/N2 gases has shown to be enhanced with the introduction of surface cations into the framework, demonstrating a mechanism that can be exploited for gas separation applications.