title: Removal of cadmium(II) ions from aqueous solution using Ni (15 wt.%)-doped α-Fe2O3 nanocrystals: equilibrium, thermodynamic, and kinetic studies.
abstract: 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.
authors.affiliation: Department of Chemistry, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia E-mail: mamhamed@imamu.edu.sa.
authors.forename: Mohamed
authors.initials: M
authors.lastname: OuldM'hamed
authors.affiliation: Department of Chemistry, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia E-mail: mamhamed@imamu.edu.sa.
authors.forename: L
authors.initials: L
authors.lastname: Khezami
authors.affiliation: Department of Chemistry, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia E-mail: mamhamed@imamu.edu.sa.
authors.forename: Abdulrahman G
authors.initials: AG
authors.lastname: Alshammari
authors.affiliation: Département de Chimie, Faculté des Sciences et Techniques, Université des Sciences, de Technologies et de Médecines (USTM), Nouakchott, Mauritanie.
authors.forename: S M
authors.initials: SM
authors.lastname: Ould-Mame
authors.affiliation: Department of Physics, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia; Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences, Gabes University, Gabes, Tunisia.
authors.forename: I
authors.initials: I
authors.lastname: Ghiloufi
authors.affiliation: Department of Physics, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia.
authors.forename: O M
authors.initials: OM
authors.lastname: Lemine
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry; D009532:Nickel / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*
chemical_list: D002104:Cadmium; D005290:Ferric Compounds; D009532:Nickel; D062065:Wastewater; C000499:ferric oxide