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The potential of polypyrrole-coated Fe₃O₄ nanoparticles (Fe₃O4@PPy NPs) for removal of two anionic dyes from aqueous solutions was studied. The dye removal process was affected by several parameters such as pH, sorbent amount, and contact time, and were optimized using the response surface methodology (RSM) based on orthogonal central composite design (OCCD). The maximum removal of dyes was achieved at the adsorbent amount of 0.1–0.12 g/100 mL at pH 4–5.4 in 60 min. Three kinetic models; namely, pseudo-first-order, pseudo-second-order, and intra-particle diffusion were used to analyze the adsorption mechanism. The kinetic results showed that the pseudo-second-order equation was the best model. The isotherm analysis indicated that the equilibrium data were well fitted to the Langmuir isotherm model, showing a monolayer adsorption manner of the dyes onto a homogeneous surface of …