Design and fabrication the novel polymeric magnetic boehmite nanocomposite (boehmite@ Fe3O4@PLA@SiO2) for the remarkable competitive adsorption of methylene blue and mercury ions

The main aim of this study is to fabricate the magnetic polymeric nanocomposite supported on the mesoporous boehmite by the facile preparation method. The core-shell magnetic boehmite was synthesized by the coprecipitation method. The coverage of polymeric layers (polylactic acid) was applied to modify the surface of magnetic boehmite for the adsorption of methylene blue and mercury ions in the single and binary solutions. The prepared samples were characterized by employing general tests including XRD, FTIR, FESEM, TEM, XPS, BET and VSM. TEM and FESEM images displayed the well dispersed nanoparticles in the structure of nanocomposites with size of less than 40 nm. The isotherm adsorption of the adsorbent was evaluated by using Langmuir, Freundlich and the extended Langmuir in the single and multicomponent aqueous solutions. The experimental data was in the good agreement with Langmuir equation in the both unary and co-adsorption process. The capacity of the magnetic polymeric nanocomposite was measured to be 70.03 and 36.94 mg/g for the adsorption of methylene blue and mercury ions, respectively. The amount of adsorbed mercury and methylene blue ions in the competitive adsorption was calculated to be 14.93 and 10.17 mg/g, respectively. The kinetic study was also conducted by two various models including pseudo first and second order models. The results indicated that the pseudo second order can justify the adsorption in the single and binary solutions. Reusability of the prepared sample in the competitive adsorption for six cycles indicated the appropriate performance of the used adsorbent for the industrial applications.