Synthesis and characterization of molecularly imprinted magnetite nanomaterials as a novel adsorbent for the removal of heavy metals from aqueous solution

摘要

For simultaneous water purification from both inorganic and organic pollutants, a novel multifunctional hybrid nanoadsorbent has been produced. Molecularly imprinted (MI) magnetic submicron-particles with iron oxide core and silica shell (Fe3O4/SiO2) were used as a substrate for immobilization of different functions. The activity towards heavy metals was provided via attachment of ethylene diamine tetra acetate (EDTA) silica-coated magnetite nanomaterials; then their use in the immobilization of MI magnetite nanomaterials (Fe3O4/SiO2/Thermo sensitive/EDTA-CS) to the silica surface with subsequent chemical grafting of ethylene diamine tetra acetate (EDTA) on which coupling occurred via an chitosan bonding. XRD spectra revealed the cubic spinel nature of nanoparticles with an average particle size 20nm and have phase stability besides. In addition to this, monodispersity of the nanoparticles was confirmed due to the size distribution of the particles. The EDX study also established the elemental ratio of EDTA functionalized silica coated magnetite nanoparticles (Fe3O4/SiO2/Thermosensitive/EDTA-CS). FT-IR spectral analysis revealed that the successful grafting of –COOH functional groups from EDTA on the surface of silica coated magnetite nanoparticles. Magnetic properties are found to be super paramagnetic at room temperature analyzed by VSM. The functionalization of EDTA on the surface of silica coated magnetite nanoparticles provides –COOH group and –NH2 group to be bonded with heavy metals from contaminated water by physicochemical interactions (physisorption and chemisorption). The effects of the adsorption process were studied with these parameters such as pH, contact time, adsorbent dose, temperature, and initial concentration (heavy metals). The Langmuir, Freundlich and Temkin adsorption isotherm models were applied to describe equilibrium data. The desorption study, as well as its reusability and recyclability, were accessible that indicates magnetite nanocomposites succeeding adequately.