Capturing CO2 with Amine-Impregnated Titanium Oxides

A series of porous titanium oxides was synthesized using different alkylamines and modified by amines, including diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA), for CO2 capture. These new composite CO2 sorbents were characterized by powder X-ray diffraction, transmission electron microscopy, nitrogen adsorption, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Their CO2 capture performances were evaluated in a fixed-bed reactor equipped with online mass spectroscopy. Experimental results revealed that CO2 uptake capacities of the titania composite sorbents increase with amine loading but decrease with the size of impregnated amines. The highest CO2 sorption capacity achieved with the sorbents is 2.64 mmol/g. It is also found that, besides the surface area and pore volume, the pore size of the support also plays an important role in determining the CO2 uptake capacity of the composite sorbents. In addition to their high CO2 adsorption capacities, the amine-impregnated titanias exhibit good stability and regenerability.