ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Investigation of isotherm and thermodynamic parameters of adsorption of copper (II) ions in aqueous solution with natural mixed type Siirt clay (NMTSC-2) and new (second) linear equation derived from Harkins–Jura isotherm

Nilgün Onursal and Mehmet Can Dal

Faculty of Education, Department of Science Education, Siirt University, Siirt, Turkey

E-mail: nilgun.onursal@gmail.com

Received: 21 May 2023  Accepted: 25 September 2023

Abstract:

In this study, it was aimed to remove Cu (II) ions from the aqueous solution by Natural Mixed Type Siirt Clay (NMTSC-2) from the aqueous solution. NMTSC-2 (clay containing chlorite, montmorillonite, vermiculite, muscovite, kaolinite and illite) was characterized by analysis methods of X-ray fluorescence spectroscopy (XRF), Fourier transform infrared, (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM-EDS), Brunauer–Emmett–Teller (BET) and thermogravimetric analysis (TGA). The data obtained as a result of the experimental studies were applied to the Freundlich, Langmuir, Temkin, Elovich and Dubinin–Radushkevich (D–R), Harkins–Jura adsorption isotherms. In the study, a new linear equation was derived from the Harkins–Jura model. The new form was applied to the NMTSC-2 adsorption experiment of Cu (II), the obtained constants and the plots were given in the study. In order to compare the models, the results were subjected to regression analysis. The new linear equation was found to be the most suitable model for the experimental data. The Langmuir model was the second most compatible with the experimental data. In adsorption experiments were performed at 298, 308 and 318 K temperatures, Cu (II) ion q_m values were found as 21.146, 25.380 and 29.850 mg g⁻¹, respectively. Thermodynamic data for 298,308 and 318 K temperatures were found as ΔG = − 24.394, − 33.724 and − 43.054 kJ mol⁻¹ ΔH = 53.039 kJ mol⁻¹, ΔS = 0.181 kJ mol⁻¹ K⁻¹.

Keywords: Adsorption isotherm; New Harkins–Jura isotherm model; Adsorption thermodynamics; Copper (II); Clay

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03116-4

Chemical Papers 78 (2) 749–760 (2024)