Efficiency comparison of single and binary mixture adsorption processes of lead (II) and 2, 4-D by bi-functional magnetic iron oxide nanoparticles from water matrix: kinetic studies

Nowadays,due to the irreparable effects imposed on aquatic ecosystems,organisms and humans,the removal of heavy metals and herbicides from water sources has extremely become vital.In recent years, the process of adsorbing contaminants with magnetic nanoparticles has gained lots of attention.Therefore, the present study aimed to synthesize nanoparticles as an adsorbent for adsorption of the contaminants of Pb and 2,4-D from water.

To evaluate the effect of independent variables such as pH(3-11),contact time(0-150min),adsorbent dose(0.2-1.2g/L) and adsorbate concentration(5-50mg/L) on the contaminant removal and determine the optimal conditions, the method of one factor at the time was used by design expert software. Nanoparticles were synthesized via a co-precipitation method and their morphology were characterized by TEM,XRD,FT-IR and SEM. Finally, the experiments were performed on aqueous solution.

Structural analysis revealed that adsorbent has a spherical structure with a Fe3O4 core and SiO2 shell, modified by both amine and thiol functional groups.The results of experiments showed that the maximum adsorption efficiency of single system occurred at pH 5 and contact time 40 min for lead and at pH6 and contact time 90min for 2,4-D.Also the optimal values of adsorbent dose and initial concentration obtained 0.8 g/L and 10 mg/L. In the binary adsorption system,the maximum adsorption efficiency determined at pH 6 and contact time 40 min for lead and contact time 60 min for 2,4-D and adsorbent dose 1.2 g/L.

According to the results,the bi-functional nanoadsorbent could be effectively used for the simultaneous removal of inorganic and organic pollutants from various aqueous solutions.