Functionalized Covalent Triazine Frameworks for Effective CO 2 and SO 2 Removal.

Building novel frameworks as sorbents remains highly significant targeting for key environmental issues like CO2 or SO2 emissions from coal-fired power plants. Here we report the construction and tunable pore structure as well as gas adsorption properties of hierarchically porous covalent triazine-based frameworks (CTF-CSUs) functionalized by appended formic acid/formate sodium groups. The densely integrated functionalities on the pore walls endow the as-made networks strong affinity toward guest acid gases, despite their moderate BET surface areas. With abundant microporosity and integrated carboxylic acid groups, our frameworks deliver strong affinity towards CO2 with considerably high enthrapy (up to 44.6 KJ/mol) at low loadings. Moreover, the formate sodium anchored framework (termed CTF-CSU41) shows an exceptionally high uptake of SO2 up to 6.7 mmol g-1 (42.9 wt %) even under a low SO2 partial pressure of 0.15 bar (298 K), representing the highest value for a scrubbing material reported to date. Significantly, such pore engineering could pave the way to broad applications of porous organic polymers.