Bagasse Activated Carbon with TETA/TEPA Modification and Adsorption Properties of CO2

摘要

Bagasse activated carbon (AC) and the new type of activated carbon (KAC) prepared with reactivation method of ZnCl2-KOH were modified with triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). The as-modified adsorbents for CO2 separation were investigated by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), elemental analysis, N-2 adsorption-desorption, as well as scanning electron microscopy (SEM). When the content of amine group is 5%, the CO2 adsorption quantity of TEPA-loaded adsorbents reaches the highest at 60 degrees C (3.62 mmol/g for KAC and 1.98 mmol/g for AC, respectively). With a more abundant pore structure, KAC is more suitable for amine modification and its adsorption capacity of CO2 is higher than that of AC after amine modification. Cyclic adsorption-desorption tests showed satisfactory regenerations for the modified adsorbents. Compared with other adsorbents, such as activated carbon, microporous zeolite, and mesoporous molecular sieve reported in literature, the new adsorbent prepared from the by-product of sugar industry has good performance (1.05-3.14 mmol/g larger than those of others) under the same conditions (60 degrees C and 15% partial pressure). The results are expected to provide scientific basis for the practical application.