Heavy Metal Ions Removal from Aqueous Solutions using NiZnFe2O4/TiO2 Nanocomposites Absorbent Siska Irma Budianti, Nurul Imani Istiqomah, Edi Suharyadi*
Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia
*Corresponding author: esuharyadi[at]ugm.ac.id
Abstract
This study investigates the adsorption performance of NiZnFe2O4/TiO2 nanoparticles on heavy metal of Cr(VI). NiZnFe2O4/TiO2 nanoparticles were successfully synthesized using coprecipitation and stober methods with various molar ratios of TiO2. The samples were characterized using x ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive x ray (SEM EDX), fourier transformation infra-red (FTIR), vibrating sample magnetometer (VSM), and ultraviolet-visible spectroscopy (UV Vis) to analyze their crystal structure, morphology, chemical bond formation, optical properties, magnetic properties, and removal efficiency. XRD results showed that NiZnFe2O4 and TiO2 have a cubic and tetragonal structure. The crystallite size decreased as the TiO2 concentration increased. TEM image of NiZnFe2O4 shows that it forms clusters and is not evenly dispersed under agglomerated conditions, with an average particle size of (10.6 plus minus 0.8) nm. FTIR analysis showed functional groups O H, C H, and H O H which indicated successful synthesis. In addition, the presence of MO octahedral, MO tetrahedral, and Ti O functional groups indicated that NiZnFe2O4/TiO2 nanoparticles had been formed. The addition of TiO2 affected to the saturation of magnetization and coercivity value in the range of 12.4 until 22.9 emu/g and 47 until 55 Oe, respectively, which indicated good magnetic properties. The absorbance spectrum of these nanoparticles was shifted to the right (redshift) so they could absorb the ultraviolet rays. The band gap of these nanoparticles varies from (2.85 plus minus 0.02) until (3.29 plus minus 0.02) eV. NiZnFe2O4/TiO2 nanoparticles with a concentration of 1:5 have good Cr(VI) removal efficiency and can reach a degradation value of 65.6%. The pseudo-kinetic model was first investigated to describe kinetic data and Cr(VI) removal determination. The SEM EDX of adsorbent after adsorption showed the presence of Cr(VI) in the nanocomposite. Therefore, these results can promote NiZnFe2O4/TiO2 nanoparticles as a promising candidate in the removal of heavy metal waste.
