Fly ash-derived mesoporous silica with large pore volume for augmented CO2 capture

•Ordered mesoporous silica with large pore volume was synthesized from fly ash without adding silicon source.•The highest reported capacity among the solid amine sorbents derived from fly ash was obtained.•The sorbents presented fast adsorption kinetics and stable cycle performance.•Recycling fly ash for CO2 capture possessed both environmental and cost advantages.