Fe ₃ O ₄ /Reduced Graphene Oxide/ZnAl‐Layered Double Hydroxides Composite for the Adsorption of Methyl Orange and Brilliant Green From Aqueous Solution

The discharge of dye‐containing wastewater poses severe ecological threats, requiring efficient and recoverable adsorbents. Here, a magnetic Fe 3 O 4 /rGO/ZnAl‐LDH composite was synthesized via a green, one‐step in situ process where graphene oxide acted as an oxidizing agent for Fe 3 O 4 generation, followed by electrostatic and hydrogen‐bonded deposition of ZnAl‐LDH platelets. The composite exhibited an enhanced BET surface area of 11.13 m 2 g −1 and a high saturation magnetization ( M s ) of 57.2 emu g −1 , enabling rapid magnetic separation. Adsorption performance was evaluated using methyl orange (MO, anionic) and brilliant green (BG, cationic). At optimal conditions, MO adsorption reached equilibrium within 60 min across pH 4–10, while BG required 360 min at pH 6–7. Nonlinear regressions revealed that both dyes followed pseudo‐second‐order kinetics and the Langmuir isotherm, yielding maximum capacities of 301.92 mg g −1 (MO) and 307.06 mg g −1 (BG). MO removal involved electrostatic interaction and anion exchange, whereas BG removal was driven by electrostatic attraction and π–π stacking. Furthermore, the composite maintained high efficiencies over five recycling cycles, demonstrating strong potential as a reusable and scalable adsorbent for wastewater treatment.