The use of amine-based absorbers

such as

N

-methyldiethanolamine (MDEA)

for CO

2

capture presents a promising strategy for emission reduction as global warming intensifies. However

high energy consumption and limited absorption/desorption efficiencies constrain its application. To address these challenges

this study developed a composite catalyst derived from fly ash (FA)

which is alkali-modified and incorporates nickel (Ni) and iron (Fe) elements

with the aim of enhancing CO

2

absorption and desorption performance while reducing energy consumption. Experimental results indicated that the Ni/FA-AM catalyst significantly improved adsorption and absorption efficiencies

achieving an 8% increase in capacity

a 63% increase in peak adsorption rate

and a reduction of 6000 s in saturation time. Studies conducted in a wetted-wall column revealed that the absorption process predominantly occurs in the liquid phase. Additionally

the catalyst demonstrated a 19% improvement in desorption performance

a 10% increase in peak desorption rate

and a 24% reduction in energy consumption

while maintaining stability over five consecutive cycles. The alkali-modified and Ni/Fe-enriched fly ash was confirmed to form active acid-base sites

facilitating the formation and disappearance of bicarbonate

thereby enhancing CO

2

capture efficiency. This was validated through XRD

BET

TPD

PY-IR

TEM

and FT-IR with

13

C NMR characterization. This study highlights the potential of modified fly ash as a low-cost and efficient catalyst for CO

2

capture.