Experimental investigation of CO2 adsorption and desorption on multi-type amines loaded HZSM-5 zeolites

Solid adsorbents were prepared by fixing amines to HZSM-5 zeolites via wet impregnation method, and the CO2 adsorption properties were investigated in a fixed-bed adsorption system followed by the structural, thermodynamic and kinetic studies. The HZSM-5 with 25 in Si/Al ratio and similar to 2.3 mu m in average particle size was found to be a favourable CO2 adsorbent support; whereby CO2 adsorbents supporting monoethanolamine (MEA) and hydroxyethyl ethylenediamine (AEEA) exhibited good CO2 adsorption capacities, with maximum values of 4.27 and 4.44 mmol/g being achieved, respectively. Desorption kinetics and thermodynamic studies showed that the CO2 desorption process of AEEA loaded HZSM-5 exhibited a low activation energy of 54.27 kJ/mol. This low activation energy attributes to two possible reasons: HZSM-5 zeolite provides a large number of free H+ ions, which directly participate in carbamate breakdown; HZSM-5 can also provide metal atoms (Al) that attach to the N atom of carbamate, thereby stretching the C-N bond and promoting decomposition. Furthermore, the AEEA loaded HASM-5 adsorbent has high adsorption-desorption stability in the regeneration cycle tests, revealing the energy efficiency of the CO2 desorption process and low CO2 capture cost.

Automated summary

Solid adsorbents were prepared by fixing amines to HZSM-5 zeolites via wet impregnation method, and the CO2 adsorption properties were investigated in a fixed-bed adsorption system followed by the structural, thermodynamic and kinetic studies. The study found that HZSM-5 zeolite with a Si/Al ratio of 25 and an average particle size of about 2.3 μm is an effective CO2 adsorbent support, and CO2 adsorbents supporting MEA and AEEA exhibit good CO2 adsorption capacities. The AEEA loaded HZSM-5 adsorbent shows high adsorption-desorption stability in the regeneration cycle tests, indicating energy efficiency in the CO2 desorption process and low CO2 capture cost.