Effect of Aliphatic Diamine Length Functionalized Silica Coated Iron Magnetic Nanoparticles on Metal Capacity and Speed of Cu(II) Uptake from Aqueous Media

Abstract

Three solid phase extractors based on silica coated magnetic nanoparticles (Fe₃O₄–SiO₂) functionalized aliphatic diamines were synthesized. The magnetic core of Fe₃O₄ was synthesized first by the sol-gel method, then protected by a layer of silica using tetraethylorthosilicate (TEOS) followed by functionalization using three aliphatic diamines: 1,2-ethanediamine (1,2-EDA), 1,5-pentanediamine (1,5-PDA) and 1,8-octanediamine (1,8-ODA). These steps for producing the targeted three adsorbents Fe₃O₄–SiO₂–1,2-EDA, Fe₃O₄–SiO₂–1,5-PDA and Fe₃O₄–SiO₂–1,8-ODA with different amines spacer arm were followed up using Fourier Transform Infrared (FTIR) spectra and scanning electron microscope (SEM). The effect of the spacer arm length of the diamines on selective binding and metal capacity values of Cu(II) ions was studied as a function of the time needed to attain equilibrium under optimized conditions of pH, mass of adsorbent and initial concentration of Cu(II) ions. The order of increasing metal capacity for copper ions using magnetic nano-adsorbents was Fe₃O₄–SiO₂–1,2-EDA < Fe₃O₄–SiO₂–1,5-PDA < Fe₃O₄–SiO₂–1,8-ODA at 5 s equilibrium time.