Facile synthesis of low-crystallinity LiAlFe-LDO from waste Al foil for efficient photo-fenton-like degradation of methylene blue

Abstract The development of low-cost and highly active materials for the removal of organic dyes from industrial wastewater is a significant research objective in the field of environmental remediation. This study proposes a sustainable waste-valorization strategy to fabricate functional materials. Fe-doped lithium aluminum layered double oxides (LiAlFe-LDO) with a hierarchically porous structure were successfully synthesized using waste aluminum foil as the aluminum source through a combination of in situ hydrothermal growth and low-temperature controlled calcination. The introduction of Fe induces the formation of fine layered double hydroxide (LDH) nano-sheet arrays on the surface of aluminum foil. The low-crystallinity LiAlFe-LDO obtained through low-temperature calcination at 300 °C possesses both a high specific surface area (139.87 m 2 g −1 ) and a narrowed band gap (2.36 eV). Consequently, the optimal sample (Li/Al/Fe = 3/1/0.125, 300 °C) exhibits excellent synergistic adsorption-photocatalytic performance for the removal of methylene blue (MB). Specifically, the catalyst achieved ∼20% removal via dark adsorption (30 min), followed by complete degradation under visible light irradiation within the subsequent 60 min. This study achieves the high-value utilization of waste aluminum resources and suggests the critical role of defect engineering in the design of efficient environmental catalytic materials.