Response surface methodology for removal of copper (II) ions from aqueous solutions by DMSA@SiO2@Fe3O4 nanocomposite

Cu (II) pollution has become a serious environmental issue in recent years due to the increasing discharge of wastewater containing copper. Consequently, it is necessary to treat copper-containing wastewater before it is discharged into the environment. Among the various methods of removing copper ions (Cu2+) from aqueous solutions, adsorption is considered to be one of the most efficient, economical and low-cost methods. In the present work, magnetic nanoparticles (Fe3O4 NPs) functionalized with silica (SiO2) and 2, 3-dimercaptosuccinic acid (DMSA) were synthesized using a facile coprecipitation method. The prepared DMSA@SiO2@Fe3O4 nanocomposite was evaluated as a magnetic adsorbent in the removal of Cu2+ from aqueous solutions. The nanocomposite exhibited fine colloidal stability, increased dispersibility and better magnetization as confirmed by zeta potential, dynamic light scattering (DLS) measurements and vibrating sample magnetometer (VSM). Using Design-Expert software, a statistical technique Box-Behnken design (BBD) and response surface methodology was employed to investigate Cu2+ removal using three adsorption parameters: pH, contact time and Cu2+ concentration. The maximum copper removal was found to be 97.1% under the optimal conditions at pH 7, contact time of 109 min and Cu2+ concentration of 163 ppm. Moreover, the adsorption process followed pseudo-first-order kinetics and was well fitted by Langmuir isotherm. Accordingly, this design procedure for making magnetic nanoadsorbents can be applied to a variety of environmental applications. [GRAPHICS] .