Removal of cadmium(II) ions from aqueous solution using Ni (15 wt.%)-doped α-Fe2O3 nanocrystals: equilibrium, thermodynamic, and kinetic studies

• Published in: Water science and technology 2015-01, Vol.72 (4), p.608-615
• Main Authors: OuldM'hamed, Mohamed, Khezami, L, Alshammari, Abdulrahman G, Ould-Mame, S M, Ghiloufi, I, Lemine, O M
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Aqueous solutions; Cadmium; Cadmium - chemistry; Cadmium base alloys; Capacity; Carbon; Cellulose acetate; Chemical engineering; Efficiency; Endothermic reactions; Enthalpy; Entropy; Equilibrium; Ferric Compounds - chemistry; Free energy; Hazardous materials; Heavy metals; Hydrogen-Ion Concentration; Ions; Iron oxides; Kinetics; Magnetometers; Mechanical alloying; Metal ions; Metal Nanoparticles - chemistry; Metals; Models, Theoretical; Nanocrystals; Nanomaterials; Nanoparticles - chemistry; Nanostructure; Nickel; Nickel - chemistry; Nitrates; Order parameters; Parameters; Petroleum production; Reaction kinetics; Removal; Solutions; Stainless steel; Temperature; Waste Disposal, Fluid - methods; Waste Water - analysis; X-ray diffraction
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2015.245

The present publication investigates the performance of nanocrystalline Ni (15 wt.%)-doped α-Fe2O3 as an effective nanomaterial for the removal of Cd(II) ions from aqueous solutions. The nanocrystalline Ni-doped α-Fe2O3 powders were prepared by mechanical alloying, and characterized by X-ray diffraction and a vibrating sample magnetometer. Batch-mode experiments were realized to determine the adsorption equilibrium, kinetics, and thermodynamic parameters of toxic heavy metal ions by Ni (15 wt.%)-doped α-Fe2O3. The adsorption isotherms data were found to be in good agreement with the Langmuir model. The adsorption capacity of Cd(II) ion reached a maximum value of about 90.91 mg g(-1) at 328 K and pH 7. The adsorption process kinetics was found to comply with pseudo-second-order rate law. Thermodynamic parameters related to the adsorption reaction, free energy change, enthalpy change and entropy change, were evaluated. The found values of free energy and enthalpy revealed a spontaneous endothermic adsorption-process. Moreover, the positive entropy suggests an increase of randomness during the process of heavy metal removal at the adsorbent-solution interface.