Synthesis of BEA zeolite from coal fly ash nano-silica extract: application in CO2 adsorption

• Circular economy approach : Valorization of coal fly ash into BEA zeolite for carbon capture. • High crystallinity : 89 – 91% confirmed by XRD and SEM. • Enhanced textural properties : Surface area increased from 54 m 2 /g to 547 m 2 /g. • Superior CO 2 uptake : 3.24 mmol/g at 273 K and 1.2 bar. • Robust stability : ∼9% performance loss after 10 adsorption–desorption cycles.