Absorbents with high breakthrough efficiency and weak host-guest interaction are considered to be promising candidates for an energy-saving process in feasible pressure/volume swing adsorption (PSA/VSA). Herein, two groups of finely designed Fe- and Co-based porous coordination polymers (PCPs) are proposed and validated; these possess hourglass-shaped nanochannels, through the cooperation of T-shaped ligands with shifted methyl groups. Featuring optimal nanochannels, high static adsorption, and relatively lower binding energy, one of these polymers, named NTU-30, enables significant C2 H6 /CH4 and C2 H4 /CH4 breakthrough efficiency, with approximately 1.0 or 0.6 g CH4 (100 %) harvested from the corresponding mixtures using 1 g of sample at ambient temperature. Furthermore, the positive effect of aromatic sites within NTU-30 is detected and investigated through an in situ IR study.
Keywords: IR spectroscopy; breakthrough efficiency; hourglass-shaped nanochannel; methane purification; porous coordination polymers.
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