Type a zeolite from red mud and fly ash for sustainable MB removal: Performance and mechanistic insights

Red mud and fly ash were valorized into A‐type zeolite via an alkali fusion–hydrothermal crystallization route for methylene blue (MB) removal. Under optimized conditions, LTA‐structured zeolite with a Si/Al ratio near 1 was successfully obtained, exhibiting well‐defined cubic morphology and uniform elemental distribution. The material possessed a hierarchical pore structure with a specific surface area of 82.48 m 2 g −1 . Adsorption experiments demonstrated rapid MB uptake, reaching equilibrium within ~20 min and achieving 90% removal at pH 7. The adsorption isotherms were best described by the Langmuir model, with a maximum capacity of 155 mg g −1 , while the kinetics followed a pseudo‐second‐order model. Mechanistic investigations, integrating pH effects, coexisting ions, FTIR, and XPS analyses, revealed that MB removal was governed by electrostatic attraction, ion exchange, and synergistic surface and pore interactions involving oxygen‐containing functional groups. Notably, the adsorbent retained a capacity of 70.8 mg g −1 after five cycles, indicating good reusability. This study provides an effective strategy for converting industrial solid wastes into high‐value adsorbents and highlights their potential for sustainable treatment of dye‐containing wastewater.