Kinetic Study of Sorption and Desorption of Cr(VI) and Mn(VII) from Aqueous Solution Using Activated Carbon

Authors

• Aveen M. Hanna, Department of Chemistry, College of Science, University of Salahaddin, Erbil, IraqFollow
• Rounak M. Shariff, Department of Chemistry, College of Science, University of Salahaddin, Erbil, IraqFollow

Abstract

This research evaluated activated carbon prepared from Lantana camara charred (LCC) and olive stone charred (OSC) for the adsorption of chromium (VI) and manganese (VII) ions from aqueous solutions. Analytical methods such as XRD, SEM, EDX and FTIR demonstrated that the materials have highly porous surfaces. Adsorption tests were conducted using comprehensive statistical physics models for Cr(VI) and Mn(VII) at three temperatures (25,40 and 55 °C) and at two pH levels (3and5), respectively. The adsorption capacity was determined by the Langmuir model, with monolayer adsorption peak values recorded at 55 °C for Cr (VI) and Mn(VII) for each adsorbent –metal pair: LCC/Cr, LCC/Mn, OSC/Cr and OSC/Mn. Preliminary results revealed a high adsorption capacity (11.111 mg/g) for Mn(VII) on OSC, while the desorption capacity was (1.111 mg/g), suggesting the presence of multiple active sites and adsorption mechanisms, Whilst the kinetic model of pseudo-second-order suggests chemisorption, it is important to note that chemisorption includes stronger interactions than physical adsorption, involving covalent bonds, exchange of ions, or complex formation. Nevertheless, the obscurity of evidence of the production of a chemical bond in our study suggests that adsorption may involve a combination of physical and chemical adsorption mechanisms. This dual nature is common in processes of adsorption, where an initial physical adsorption is followed by slower chemisorption. Thermodynamic analyses indicated that the adsorption process is endothermic, spontaneous, and driven by chemisorption, influenced by chemical and physical interactions. The results show that LCC and OSC are effective in removing Cr(VI) and Mn(VII) from aqueous solutions.

Keywords

Activated, Adsorption, Carbon, Isotherm, Kinetic, Thermodynamics

Subject Area

Chemistry

Article Type

Article

First Page

1378

Last Page

1397

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite this Article

Hanna, Aveen M. and Shariff, Rounak M. (2026) "Kinetic Study of Sorption and Desorption of Cr(VI) and Mn(VII) from Aqueous Solution Using Activated Carbon," Baghdad Science Journal: Vol. 23: Iss. 4, Article 18.
DOI: https://doi.org/10.21123/2411-7986.5266