Cadmium removal from aqueous solution by iron oxide coated sepiolite: preparation, characterization and batch adsorption studies

KIPÇAK İ., Akin C.

DESALINATION AND WATER TREATMENT, vol.146, pp.245-256, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 146
  • Publication Date: 2019
  • Doi Number: 10.5004/dwt.2019.23606
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.245-256
  • Eskisehir Osmangazi University Affiliated: Yes


In this study, iron oxide coated sepiolite (IOCS) as a new composite adsorbent was synthesized and employed for the removal of Cd(II) ions from aqueous solutions by adsorption. The synthesized composite was characterized by X-ray diffractogram, X-ray fluorescence, BET, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy analyses. Batch adsorption experiments were conducted to investigate the effects of adsorbent dosage, pH, contact time, initial concentration and temperature on the cadmium ions uptake. The kinetics of adsorption has been studied, and various kinetic models, such as pseudo-first-order, pseudo-second-order and intraparticle diffusion models were tested with experimental data for their validity. The pseudo-second-order kinetic model was determined to correlate well to the experimental data. The Langmuir and Freundlich isotherms were utilized for the analysis of adsorption equilibrium. The Langmuir isotherm gave a better fit for Cd(II) adsorption and the maximum loading capacity was found as 98.04 mg g(-1) at 25 degrees C. This value was almost three times bigger than that of raw sepiolite. The calculated thermodynamic parameters showed that the adsorption of Cd(II) ions is feasible, spontaneous and endothermic in nature. Experimental results indicated that the IOCS appear to be a promising adsorbent material for the removal of cadmium ions from aqueous media.