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Abstract This study demonstrates the successful, facile, and cost-effective preparation of magnetic Fe 3 O 4 nanoparticles (MNPs) via green procedure using Cordia myxa leaf extracts for efficient adsorption of methylene blue (MB) as a model of organic pollutant. The formation of Fe 3 O 4 NPs was confirmed by a range of spectroscopy and microscopy techniques including FT-IR, XRD, FE-SEM, TEM, EDS, VSM, TGA, and BET-BJH. The synthesized spherical nanoparticles had a high specific surface area of 115.07 m 2 /g with a mesoporous structure. The formed Fe 3 O 4 MNPs exhibited superparamagnetic behavior with saturation magnetization of 49.48 emu/g. After characterization, the adsorptive performance of the synthesized MNPs toward MB was evaluated. To achieve the maximum removal efficiency, the effect of key parameters such as adsorbent dosage (MNPs), initial adsorbate concentration, pH, and contact time on the adsorption process was evaluated. A maximum adsorption capacity of 17.79 mg/g was obtained, after one-hour incubation at pH 7.5. From the pH PZC of 7.1 of the synthesized adsorbent, the electrostatic attraction between MB and Fe 3 O 4 NPs plays an important role in the adsorption process. The adsorption experimental data showed the closest match with the pseudo-second-order kinetic and Langmuir isotherm. The prepared Fe 3 O 4 NPs were easily recovered by an external magnet and could be reused several times. Therefore, the synthesized MNPs seem to be excellent adsorbents for the removal of MB from aqueous solution.
Ghoohestani et al. (Tue,) studied this question.