Sustainable aerogel synthesis via waste-upcycling: Municipal solid-waste incineration fly ash-derived aerogels for U(VI) adsorption and CO2 capture

초록

This study reports a sustainable and low-cost acid-epoxide sol-gel method with ambient drying to convert municipal solid-waste incineration fly ash (MSWIFA) into mesoporous aerogels (BET: 265-272 m(2)/g), which are comparatively higher than GGBFS (196 m(2)/g) and CaCl2-based aerogels (BET: 3.8 m(2)/g). This is the first reported synthesis of epoxide-assisted MSWIFA aerogels for waste upcycling. XRD showed amorphous MSWIFA residues (2 theta = 11.7-47.9(o)), FTIR confirmed Si-O-Al/Ca (1040-1105 cm(-1)), and FE-SEM/EDS revealed Ca-O rod networks supporting Langmuir monolayer adsorption (Q(max): 111-125 mg/g) and pseudo-second-order kinetics with faster reaction rates than GGBFS (Q(max): 50 mg/g) and Ca-aerogels (Q(max): 30 mg/g) at pH 7. Zeta-potential shifts and post-adsorption XPS/EDS confirmed electrostatically assisted inner-sphere uranyl complexation on the deprotonated sites, achieving >94% recyclability over five cycles via simple desorption. CO2 physisorption demonstrates MSWIFA aerogels achieve 0.54 mmol/g at 273 K with good recyclability. This waste-upcycling strategy yielded cost-effective dual-function sorbents for nuclear wastewater remediation and carbon capture.

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