@article{scholars12925,
         journal = {SN Applied Sciences},
            year = {2020},
       publisher = {Springer Nature},
            note = {cited By 32},
             doi = {10.1007/s42452-020-2968-9},
          number = {7},
           title = {Extension of BET theory to CO2 adsorption isotherms for ultra-microporosity of covalent organic polymers},
          volume = {2},
            issn = {25233971},
        keywords = {Adsorption; Adsorption isotherms; Argon; Carbon dioxide; Cryogenics; Desorption; Microporosity; Microporous materials; Nitrogen; Specific surface area, Argon adsorption; CO2 adsorption; Cryogenic conditions; Cryogenic temperatures; Desorption isotherms; Linear region; N2 adsorption; Surface area, Organic polymers},
          author = {Mukhtar, A. and Mellon, N. and Saqib, S. and Lee, S.-P. and Bustam, M. A.},
        abstract = {Usually, nitrogen and argon adsorption{\^a}??desorption isotherms are used at their respective boiling points for the determination of specific surface area via the BET theory of microporous materials. However, for ultra-micropores, where nitrogen and argon cannot access at cryogenic temperatures, the CO2 adsorption{\^a}??desorption isotherms have been considered as alternative options for the determination of specific surface area by extending BET theory, but the surface area determined by using CO2 adsorption{\^a}??desorption isotherms is not significant due to strong CO2-CO2 interactions. In this study, the microporous covalent organic polymers are subjected to nitrogen and CO2 adsorption{\^a}??desorption isotherms and the results showed that a clear linear region is available in isotherms, which confirms the presence of ultra-micropores. The surface area determined by the CO2 adsorption{\^a}??desorption isotherms is higher than the surface area determined by N2 adsorption{\^a}??desorption isotherms. These results indicate that the microporous covalent organic polymers contain ultra-micropores where only CO2 can reach, while nitrogen and argon cannot access at cryogenic conditions because their kinetic diameter is larger than CO2. {\^A}{\copyright} 2020, Springer Nature Switzerland AG.},
             url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096140500&doi=10.1007\%2fs42452-020-2968-9&partnerID=40&md5=f808294fa5ef668716429abfa6b9a5cc}
}