Energy efficient carbon dioxide capture with thermomorphic solvents at lower cycle temperatures

The present study introduced a new thermomorphic absorbent composed of N-methylcyclohexylamine and N,Ndimethylcyclohexylamine. This absorbent achieved a maximum CO2 absorption capacity of 0.1134 g CO2/g solvent when the molar ratio of N,N-dimethylcyclohexylamine to N-methylcyclohexylamine was optimized to 4:1. Desorption tests conducted at temperatures of 323 K, 333 K, and 343 K using a water bath showed consistent desorption efficiencies exceeding 90 % across a range of solution concentration ratios. In addition, aminofunctionalized multi-walled carbon nanotubes were employed as photothermal conversion agents to enhance desorption under sunlight, yielding desorption efficiencies comparable to those obtained through the water bath method. Energy consumption analysis revealed that the D3M1 absorbent required only 1.04 GJ/ton COQ, representing a significant 73.9 % reduction in energy usage compared to the conventional 30 wt% monoethanolamine solution. The absorbent's effective CO2 capture at lower cycling temperatures demonstrates its considerable potential for future energy-efficient CO2 capture applications.