Dendrimer modified magnetite particles for heavy metal (copper(II), cobalt(II), zinc(II), nickel(II)) removal from water

Huang, Chin-PaoIn this study, magnetite particles were synthesized and functionalized with (3-aminopropyl)trimethoxysilane (APTS) to obtain Generation 0 Poly(amidoamine) (PAMAM) dendrimer modified magnetite particles. Particles were tested for the adsorption of Cu(II), Co(II), Zn(II), and Ni(II) from aqueous system. Magnetite particles were synthesized by coprecipitation under optimized reaction condition. Various parameters that may affect particle size, such as iron ratio, temperature, heating time, and mixing speed were tested. X-ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), Dynamic Light Scattering (DLS), and Zeta-potential were used to characterize magnetite particles. XRD shows particles were in the form of Fe 3 O4 ; VSM shows that the saturate magnetic moment of magnetite was 60.8 emu/g; DLS shows that the diameter of particle was 158 ?? 8 nm; pHzpc was 4.4. To modify the magnetite, APTS was introduced to form G0 (1st generation) dendrimer on the surface of magnetite particle. Zeta-potential was used to characterize the particle and it showed that the pHzpc of dendrimer modified particle was 9.6. Four heavy metal, Cu(II), Co(II), Zn(II), and Ni(II), were used as adsorbate to test the metal adsorption capacity of this material. Cu(II), Ni(II), Zn(II), and Co(II) was totally removed at pH 6.7, 7.3, 7.5, and 9.3, respectively. Cu(II) was easily removed and Co(II) was the most difficult one to be removed by following the decresasing order: Cu(II) > Ni(II) > Zn(II) > Co(II). The highest net removal efficiency of Ni(II), Cu(II), Zn(II), and Co(II) was 85, 65, 55, and 42%, respectively. The adsorption behavior of the above four heavy metals can be described by the Langmuir model. Key word: magnetite, PAMAM dendrimer, heavy metal, adsorptionUniversity of Delaware, Department of Civil and Environmental EngineeringM.C.E