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Factors Affecting the Efficiency of Ferrite Process for Removal of Heavy Metals (Case study of Chromium and Nickel)

Abdolshahinejad, Sara | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44913 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Borgheei, Mahdi
  7. Abstract:
  8. Heavy metals, present in many industrial wastewaters, are considered as major pollutants of environment. Various methods to removal heavy metals effectively from effluents have been used in industry, yet more efficient and economical methods are required. Magnetic iron nanoparticles are known for their superior adsorption, ion exchange and electro-static forces characteristics.The aim of this study was to evaluate the efficiency of magnetic nanoparticles for removal of hexavalent chromium (VI) and Divalent nickel from wastewater and the parameters that influence the removal.The magnetite nanoparticles were prepared by co-precipitation method where produced Fe3O4 nanoparticle’s average size was 35 nm. Synthetic wastewater containing different concentrations of chromium and nickel was used throughout the experimentation. Various factors influencing the adsorption of metal ions, e.g., pH, temperature, amount of adsorbent (magnetic nanoparticles), initial concentration of chromium and nickel, and contact time were investigated to optimize the operational conditions of the process.Results indicated that the mechanism was strongly influenced by solution pH, similar to many adsorption processes. At pH= 2, while initial concentration of chromium was 30 mg/L and a dose of 3.5 g/L synthesized magnetite nanoparticles was added, in 20 minutes contact time 94 % of chromium (VI) was removed. At higher pH levels of the solution, efficiency of removal declined. Similar experiment at pH= 11, 30 mg/L initial nickel concentration, a dose of 5 g/L magnetite nanoparticle and 20 minutes contact time, about 99.85% of nickel was removed. However nickel adsorption was less dependent to pH compare to chromium adsorption. Final results proved that magnetite nanoparticles have high capacity for removal of chromium (VI) and nickel from solutions containing these salts, and removal efficiency for chromium(VI) is reversely related to pH, while for nickel removal, pH is less sensitive. The results also showed the adsorption was decreased by increasing the initial concentrations of Ni(II) and chromium(VI) in solutions. As expected an increase in adsorbent dosage increased the removal of Ni(II) and chromium (VI).
    Equilibrium isotherms were analyzed by Langmuir and Freundlich adsorption models and the results proved that the behavior of chromium and nickel adsorption by Ferro-magnetic nano-particles is best expressed by Langmuir isotherm
  9. Keywords:
  10. Nanoparticles ; Heavy Metals ; Adsorption ; Magnetite Nanoparticle

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