Biomaterials for CO2 Harvesting: From Regulatory Functions to Wet Scrubbing Applications.

Abstract

A new series of 2-aminoethyl-benzene-based biomaterials, namely, dopamine (DOP), tyramine (TYR), phenylethylamine (PEA), and epinephrine (EPN), dissolved in dimethylsulfoxide (DMSO) have been investigated for CO2 capture upon activatiing their hydhydrochloride salts with a NaOH pellet. Spectroscopic measurements, including ex situ ATR-FTIR, 1D and 2D NMR experiments have been applied to verify the formation of the sodium carbamate adducts (RR′N-CO2– Na+). The emergence of new peaks in the IR spectra ranging between 1702 and 1735 cm–1 together with the chemical shift within 157–158 ppm in the 13C NMR, as well as with cross-peaks obtained by 1H-15N HSQC measurements at ca. 84 and 6.6 ppm verified the formation of RR′N-CO2– Na+ products upon the chemical fixation of CO2. The CO2 sorption capacity of the examined biomaterials was evaluated volumetrically, with a maximum value of 8.18 mmol CO2·g–1 sorbent (36.0 (w/w)%, including both chemisorption and physisorption), for 5 (w/v)% solutions measured at 5 bar CO2 and 25 °C, for TYR and PEA. DFT calculations indicated that the intramolecular hydrogen bonding within the structural motif of EPN-N-CO2– Na+ adduct provides an exceptional stability compared to monoethanolamine and other structurally related model compounds.