Kinetics and thermodynamics of adsorption for Cd on green manufactured nano-particles

• Published in: Journal of hazardous materials 2012-10, Vol.235-236, p.116-122
• Main Authors: Tu, Yao-Jen, You, Chen-Feng, Chang, Chien-Kuei
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; Atmospheric pollution; Cadmium - chemistry; Cd adsorption; Chemical engineering; Copper - chemistry; CuFe2O4; Exact sciences and technology; Ferrous Compounds - chemistry; Industrial sludge; Industrial Waste; Kinetics; Kinetics and thermodynamics; Magnetic nano-particles; Magnetic Phenomena; Metal Nanoparticles - chemistry; Models, Chemical; Pollution; Polychlorinated Biphenyls; Recycling; Thermodynamics; Water Pollutants, Chemical - chemistry; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.07.030

[Display omitted] ► A novel technology for fabricating CuFe2O4 was developed from industrial Cu sludge. ► The manufactured CuFe2O4 was effective in removing Cd2+ from contaminated water. ► The adsorbent can be rapidly recovered by a magnet because of its soft magnetism. ► Increasing pH has positive effects on the Cd2+ removal in the pH ranges of 2–6. Magnetic nano-particles CuFe2O4 were successful manufactured from industrial sludge by combination of acid leaching, chemical exchange, and ferrite process. For the first time these recycled nano-particles were used as adsorbent to investigate the kinetics and thermodynamics for adsorption of Cd in aqueous solutions. These experimental results showed that Cd2+ adsorption efficiency increased from 0.85 to 99.9% when pH increased from 2 to 6. The maximum adsorption capacity of Cd2+ was found to be 17.54mgg−1 under the conditions at pH 6.0, contact time 30min, and temperature 318K. The pseudo-second-order kinetic model provides the best correlation with the experimental data compared to the pseudo-first-order model. The Langmuir model yields a better fitting than the Freundlich model for Cd2+ adsorption on CuFe2O4 nano-particles under investigated temperatures. The thermodynamic constants of the adsorption process were evaluated, ΔG°, ΔH° and ΔS° is −6.05kJmol−1 (at 318K), 0.71kJmol−1, and 4.53Jmol−1K−1, respectively. These results imply that Cd2+ adsorption onto CuFe2O4 is feasible, spontaneous and endothermic in nature.