Biosorption Studies of Heavy Metals from Aquatic Environments Using Plant Residues: Thermodynamics and Reaction Kinetics | ||
| Egyptian Journal of Aquatic Biology and Fisheries | ||
| Article 126, Volume 29, Issue 2, March and April 2025, Pages 1867-1881 PDF (516.49 K) | ||
| DOI: 10.21608/ejabf.2025.421382 | ||
| Author | ||
| Jabr et al. | ||
| Abstract | ||
| The present study evaluated the performance of Sidr nabak leaves, Sebesten leaves, and Rachis Base in removing heavy metals from aqueous solutions. The effects of temperature, contact time, and various kinetic models—including fractional power, zero-order, first-order, pseudo-first-order, Elovich, second-order, intraparticle diffusion, and four different linearized forms of the pseudo-second-order model—were examined to fit the kinetic data. The results demonstrated that the adsorption percentage increases with rising temperatures (10, 20, 30, 40, and 50°C). By applying thermodynamic concepts—standard free energy (∆G˚), enthalpy (∆H˚), and entropy (∆S˚)—to the adsorption of heavy elements on the surfaces of plant residues at different temperatures, it was found that the adsorption reaction is spontaneous (indicated by negative ∆G˚ values), endothermic (indicated by positive ∆H˚ values), and accompanied by an increase in randomness (indicated by positive ∆S˚ values). Regarding the kinetic models (Elovich, Fractional Power, Zero-Order, First-Order, Pseudo-First-Order, Second-Order, Pseudo-Second-Order I, Pseudo-Second-Order II, Pseudo-Second-Order III, Pseudo-Second-Order IV, and Intraparticle Diffusion) applied to the data for the adsorbed amount over time, the pseudo-second-order model (in its various forms) provided the best description of the adsorption kinetic system. This model achieved the highest coefficient of determination (R²) values, accurately describing the studied data for most relationships between heavy elements and plant residues under investigation. | ||
| Keywords | ||
| Biosorption; Heavy metals; Plant residues; Thermodynamics; Kinetics | ||
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