Adsorption of copper from aqueous solutions by activated carbon prepared from peach wood

• Published in: Journal of the Iranian Chemical Society 2022-07, Vol.19 (7), p.3205-3214
• Main Authors: Sveshnikova, D. A., Suleimanov, S. I., Rabadanova, D. I., Gafurov, M. M., Akhmedov, I. R., Kakagasanov, M. G., Rabadanov, K. Sh, Asvarov, A. Sh
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorption; Analytical Chemistry; Aqueous solutions; Biochemistry; Carbonyls; Chemistry; Chemistry and Materials Science; Copper; Correlation coefficients; Fourier transforms; Free energy; Inorganic Chemistry; Ion exchange; Kinetics; Organic Chemistry; Original Paper; Phosphoric acid; Physical Chemistry; Quantum chemistry; Sorption; Surface chemistry; Titration
• ISSN: 1735-207X; 1735-2428
• DOI: 10.1007/s13738-022-02524-9

Sorption properties of activated carbon prepared from peach wood by chemical activation with phosphoric acid toward copper ions were studied. The produced activated carbons were characterized by N2 adsorption, scanning electron microscopy, Boehm titration, potentiometric titration and Fourier transform infrared techniques. The highest surface area (588 m 2 /g) and total pore volume (0.19 cm 3 /g) were obtained at a carbonization temperature of 600 °C with an impregnation ratio of 1/1. We have found that the dependence of Cu 2+ ions adsorption on their concentration in the solution on these carbons is adequately described by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm equations. The analysis of kinetic data indicates that the adsorption process is described by equations of mixed diffusion kinetics (with some predominance of external diffusion) and equations of pseudo-first- and pseudo-second-order models. Sorption kinetics describe of the ions under study shows that the pseudo-second-order equation allows describing experimental data with higher correlation coefficients R 2 . Study of the effect of the concentration of phosphoric acid used for chemical activation on the texture and sorption properties of the resulting carbons showed that the optimal concentration of H 3 PO 4 was 20%. In the present study the numerical value of adsorption of the mean free energy is 13.36 kJ mol  −1 which corresponds to ion-exchange process. Quantum-chemical calculations show that oxygen-containing (carboxyl, phenolic, carbonyl) surface groups and various phosphorus-containing groups participate in adsorption of copper ions on the carbons under consideration.