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.

Efficiency of Aluminium Pillared Montmorillonite Clays of Pakistani Origin (Peshawar And Samwal) on the Adsorption of Chromium Ions in Aqueous Solutions

“…Above pH value of 7, Cr (III) precipitates as Cr (OH) 3 and uptake of metal ions significantly decreases [35]. Similar trends of adsorption by change in pH of solution have been noted in previous studies conducted by researchers for Cr (III) [36,37] as well as for other metals such as Pb (II), Cd (II), Cu (II), and Co (II) [38,39].…”

Efficient adsorption of Cd(ІІ) ions from aqueous media onto a semi‐interpenetrating bio‐composite

“…The present study shows the best adsorption capacity of s‐IPNs‐3 is 49.75 mg g −1 of Cd(II) ions. In comparison, the adsorption capacities of many other sorbents for Cd(II) ions have been reported; 90.91 mg g −1 for nanocrystalline Ni (15 wt%)‐doped α‐Fe 2 O 3 , 94.05 mg g −1 for the oxide adsorbent MgO‐SiO 2 , 30.4 mg g −1 for 2CS‐Hhnal, and 7.407 and 9.174 mg g −1 for kaolinite and metakaolinite, respectively, 10.31 and 8.62 mg g −1 for penicone and biochar, respectively), and 88.8, 97.62, and 86.73% using expanded perlite, Fluidgel and Tectone grandis L. f. leaf powder…”

“…Several procedures have been developed for the removal of Cd(II) ions from aqueous media using chemical sorbents {nanocrystalline Ni (15 wt%)‐doped α‐Fe 2 O 3, oxides of MgO‐SiO 2, industrial and agriculture residues; kaolinite, metakaolinite, penicone, biochar, expanded perlite, Fluidgel, Tectone grandis L. f. leaf powder), and a Schiff‐base derived from chitosan and 2‐hydroxynaphthaldehyde . The negative charges on the surface of this last polymeric species allows it to attract Cd(II) ions from aqueous media—a crucial property in industrial applications…”