Methylene blue removal from aqueous solution by magnetic clinoptilolite/chitosan/EDTA nanocomposite

In this study, clinoptilolite as a natural zeolite which was magnetized using precipitation of maghemite nanoparticles was coated by chitosan and then modified by thylenediamine tetra-acetic acid to add functional groups and its performance in the removal of toxic methylene blue from aqueous solution was investigated. Synthesized magnetic nanocomposite was characterized by VSM, XRD, SEM, and FTIR analyses. The saturation magnetization of the final nanocomposite was obtained as 22.2 emu/g. In addition, the factors affecting adsorption process and its optimization were investigated using response surface methodology and central composite design. Data obtained by different isotherm, adsorption kinetic and thermodynamic models were also studied. The results showed good agreement of these data with the Freundlich isotherm model (R (2) = 0.99), and it was found that adsorption follows the second-order kinetics model (R (2) = 1). Negative values of Delta G and positive values of Delta H obtained from this adsorption thermodynamic study revealed that the methylene blue adsorption process is exothermic and spontaneous. The optimum conditions to ensure maximum adsorption efficiency were determined, and included pH = 5.54, adsorbent amount of 0.03 g, temperature of 31.18 A degrees C, and initial solution concentration of 16.21 mg/l which resulted in a removal efficiency of 99.44%. The results indicated that this nanocomposite can be used as a proper adsorbent for adsorbing methylene blue and other dye contaminants.