Characterization and investigation of natural clay performance for Methylene Blue removal: results of isotherm, kinetic and thermodynamic studies
Issue: 4/2024
Recevied: July 16, 2024
Accepted: October 17, 2024
Published: October 17, 2024
Authors:
N. Aybar, A. Kul
Categories: Pollution and environment
DOI: 10.5601/jelem.2024.29.3.3384
Abstract:
In this study, Van-Başkale (VB) clay was used for removal of Methylene Blue (MB) dye. The characterization of VB clay was carried out with the Fourier transform infrared spectra (FTIR), Brunauer-Emmett-Teller (BET), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis. The BET surface area was measured as 11.983 m2/g. FTIR spectrums were indicated that functional groups which represented the Si-H bond, N-H bond, N-O bond and Si-C stretching vibrations. SEM-EDX analysis of VB clay was showed that composition of 61.45% O, 25.70% Si, 5.89% Al, 2.82% K, 2.28% Na, 0.97% Fe, and 0.89% Ca weight. The effects of removal parameters pH (2–7), temperature (298–318 K), initial concentration (10-50 mg/L) adsorbent dosage (0.2–3.0 g/L), and contact time on adsorption were investigated. The obtained data were applied to the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models and it was seen that the Freundlich isotherm model which correlation coefficient values were higher than other isotherm models. The pseudo second order (PSO) kinetic model was the best choice for removal of MB than the pseudo first order (PFO) and intraparticle diffusion (IPD) kinetic models. Negative Gibbs free energy values obtained from thermodynamic calculations show that adsorption occurs spontaneously. The free energy of D-R adsorption calculated using the D-R isotherm was less than 8 kJ/mol, indicated that process was physical adsorption. The activation energy (EA) of this process was obtained as 29.21 kJ/mol which confirmed the fact that process was physical adsorption.
Citation:
JELEM / HARVARD
MDPI
AMA
CHICAGO
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