CO2 capture using nanoporous TiO(OH)2/tetraethylenepentamine

In this work, an inorganic-organic CO2 sorbent was prepared by immobilizing tetraethylenepentamine (TEPA) onto nanoporous titanium oxyhydrate (TiO(OH)2). The prepared sorbents were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) analyses. At the optimal TEPA loading of 60 wt% on TiO(OH)2, the CO2 sorption capacity reached 3.1 mmol CO2/g-sorbent for 1 vol% CO2 in N2 along with ∼1 vol% H2O at 60 °C. Studies of adsorption kinetics and thermodynamics showed that the activation energies for CO2 adsorption and desorption of TiO(OH)2/TEPA are 19.6 kJ/mol and 51.1 kJ/mol, respectively. This low CO2 desorption activation energy means a high CO2 desorption rate, thus a low CO2 capture cost. Accordingly, the sorbent has the potential to be used for capturing ultra-dilute CO2 from gas mixtures.