Tetraethylenepentamine modified protonated titanate nanotubes for CO2 capture

Abstract

Protonated titanate nanotube (PTNT) with large pore size and high pore volume synthesized by a hydrothermal method was modified with different amounts of tetraethylenepentamine (TEPA) through wet impregnation for CO2 adsorption. The as-synthesized adsorbents were characterized by different techniques such as nitrogen adsorption, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. CO2 capture performances of the sorbents were tested by a fixed-bed reactor equipped with an on-line gas chromatograph. The CO2 capacity of PTNT with 60wt.% TEPA loading was as high as 4.13mmol/g under the conditions of 10.0% (v/v) CO2 in N2 at 75°C, which is higher than those achieved with analogue TEPA impregnated SBA-15 and many other previously reported TEPA-impregnated materials. The high CO2 uptake is probably due to the large pore size and high pore volume of PTNT support combined with its special surface characteristics. Cyclic CO2 adsorption–desorption tests demonstrated the excellent regenerability and stability of the PTNT-based sorbent. The high CO2 uptake, positive effect of moisture and good recyclability of TEPA modified PTNT demonstrate its great potential in capture of CO2 from flue gas.