A magnetic nanocomposite adsorbent based on cress seed mucilage (CSM) was synthesized for removing methylene blue (MB) cationic dye from aqueous solutions. These adsorbent nanoparticles were prepared by in situ formation of magnetic iron oxide nanoparticles (MIONs) coupled with CSM mucilage and benefited from the advantages of both CSM and MIONs. The CSM-MIONs adsorbent exhibited a great dye adsorption capacity along with a strong magnetic character. The effect of various experimental parameters were studied on the adsorption performance of CSM-MIONs including pH, ionic strength, initial dye concentration, contact time and temperature. The adsorbent nanoparticles were characterized by FTIR, FESEM, XRD, DLS, and VSM techniques. Thermodynamic analysis indicated that the studied dye adsorption process has a spontaneous and exothermic nature. The equilibrium adsorption data were in agreement with the Langmuir kinetic model (R2 > 0.99) and described by the pseudo-second-order Langmuir equation (R2 > 0.98). It was revealed that intraparticle diffusion is not the only rate controlling factor. The CSM-MIONs adsorbents could be well regenerated using an acid solution, and showed high adsorption capability even after five desorption-adsorption cycles. The obtained results showed that the CSM-MIONs can potentially be used as a high-performance low cost adsorbent in wastewater treatment.
Keywords: Cress seed mucilage; Magnetic biosorbent; Methylene blue.
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