title: Carbon dioxide capture by an amine functionalized ionic liquid: fundamental differences of surface and bulk behavior.
abstract: Carbon dioxide (CO2) absorption by the amine-functionalized ionic liquid (IL) dihydroxyethyldimethylammonium taurinate at 310 K was studied using surface- and bulk-sensitive experimental techniques. From near-ambient pressure X-ray photoelectron spectroscopy at 0.9 mbar CO2, the amount of captured CO2 per mole of IL in the near-surface region is quantified to ~0.58 mol, with ~0.15 mol in form of carbamate dianions and ~0.43 mol in form of carbamic acid. From isothermal uptake experiments combined with infrared spectroscopy, CO2 is found to be bound in the bulk as carbamate (with nominally 0.5 mol of CO2 bound per 1 mol of IL) up to ~2.5 bar CO2, and as carbamic acid (with nominally 1 mol CO2 bound per 1 mol IL) at higher pressures. We attribute the fact that at low pressures carbamic acid is the dominating species in the near-surface region, while only carbamate is formed in the bulk, to differences in solvation in the outermost IL layers as compared to the bulk situation.
authors: Lehrstuhl für Physikalische Chemie II and ‡Lehrstuhl für Chemische Reaktionstechnik, Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany.
authors: Inga
authors: I
authors: Niedermaier
authors: Matthias
authors: M
authors: Bahlmann
authors: Christian
authors: C
authors: Papp
authors: Claudia
authors: C
authors: Kolbeck
authors: Wei
authors: W
authors: Wei
authors: Sandra
authors: S
authors: Krick Calderón
authors: Mathias
authors: M
authors: Grabau
authors: Peter S
authors: PS
authors: Schulz
authors: Peter
authors: P
authors: Wasserscheid
authors: Hans-Peter
authors: HP
authors: Steinrück
authors: Florian
authors: F
authors: Maier