Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

In this study, EDTA-functionalized Fe 3 O 4 (Fe 3 O 4 @SiO 2 -EDTA) was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups for Pb(II) and Cu(II) removal from aqueous solutions. Fe 3 O 4 @SiO 2 -EDTA composites were characterized using SEM, TEM, EDX, FTIR, XPS, TGA and saturated magnetization techniques. Maximum Pb(II) adsorption capacity was found to be 114.94   mg   g −1 with SiO 2 /EDTA molar ratio of 2.5:1. The adsorption rate was significantly fast and the equilibrium was reached within 10   min. The optimum pH was recorded to be 5.0. The maximum adsorption capacity of the studied heavy metal ions calculated by Langmuir model followed the order: Cu(II) (0.58   mmol   g −1 )   >   Pb(II) (0.55   mmol   g −1 )   ≈   Ni(II) (0.55   mmol   g −1 )   >   Cd(II) (0.45   mmol   g −1 ). Moreover, Pb(II) and Cu(II) adsorption capacities were not significantly affected by co-existing cations and NOM. These results suggested that this adsorbent can be considered as a promising adsorbent to remove Pb(II) and Cu(II) from wastewaters.