Magnetized Nanocomposite of Sea Shell and Walnut Shell-waste as Adsorbent for Efficient Removal of Methylene Blue

In this paper, nano magnetized composite of sea shell (SS) and walnut shell-waste based activated carbon (WAC), (SS/WAC/Fe3O4), was synthesized and used for the removal of methylene blue (MB) from an aqueous solution. Field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), Fourier-Transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD) and UV-Vis were used to characterize the SS/WAC/Fe3O4 nanocomposite. The SS/WAC/Fe3O4 nanocomposite proved to be an effective adsorbent in the adsorption of methylene blue (MB) in the optimized effective parameters. Effective parameters such as pH, adsorption time (min), adsorbent dosage (g/L) and initial dye concentration were optimized with Box-Behnken Design (BBD). Optimal adsorption conditions including pH=6.5, dye concentration of 4.0 mg L^-1, adsorbent amount of 0.232 g L^-1 and contact time of 40 min were obtained. Fitting the experimental equilibrium data to various isotherm models such as Langmuir and Freundlich models show the suitability and applicability of the Langmuir model. The maximum monolayer sorption capacity was 37.2 mg g^-1. More than 93% removal efficiency for MB dye showed that this adsorbent is an effective natural compound and also inexpensive for treatment processes. Therefore, using this method and process to remove dye pollutants from aqueous media is recommended.