Synthesis-structure-property relationship of nitrogen-doped porous covalent triazine frameworks for pre-combustion CO2 capture

In this work, high pressure selective CO2/CH4 adsorption over functionalized covalent triazine based frameworks (CTF-NH) have been reported at high-pressure (1-20 bar) and different temperatures. The findings revealed that the successive incorporation of amine functionalities to the CTF leads to the enhancement of CO2 and CH4 adsorption capacities by 94.99% and 3.69%, respectively. The CO2 and CH4 adsorption capacities decreased with rising temperatures. The selectivity of CO2/CH4 was improved from 2.745 to 5.145. The different adsorption isotherms showed good fitting agreement with the experimentally acquired data with a lower value (AARE and R-2) approaching to 1. The isotherm analysis exhibited that the adsorption is heterogeneous and satisfactory under these conditions. Dubinin-Radushkevich (D-R) isotherm analysis showed that the physisorption is dominant, with adsorption energy of less than 20 kJ/mol. Finally, thermodynamic properties revealed that at lower temperatures, the adsorption phenomenon is satisfactory, physical in nature, and exhibiting less disorder and randomness. (C) 2020 Elsevier Ltd. All rights reserved.