| ABSTRACT |
This invention presents a sustainable method for synthesizing an amine-modified alumina-zeolite adsorbent by valorizing spent alumina-zeolite (AZ-300), an abundant industrial scheduled waste. The synthesis method comprises thermally regenerating the spent adsorbent at a temperature ranging between 90°C and 110°C under a nitrogen atmosphere to restore its surface properties. This is followed by chemical functionalization with branched polyethyleneimine (PEI) in an ethanol solvent via wet impregnation at an optimal 1:1 amine-to-adsorbent loading ratio. Agitation at ambient temperature ensures homogeneous dispersion before the solid is filtered and dried. The introduction of PEI significantly improves the adsorbent properties (morphology, specific surface area, and pore properties) and drastically increases the number of active sites, transitioning the adsorption process from simple physisorption to robust physisorption and chemisorption multi-pathways. The resulting functionalized adsorbent exhibits a substantially enhanced sulfur dioxide (SO2) adsorption capacity (up to 143.10 mg/g). Ultimately, the synthesis method produces an adsorbent that helps to mitigate the environmental impact of industrial scheduled waste while providing a cost-effective, high-performance material for dry flue gas desulfurization (FGD), directly supporting circular economy initiatives.
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