Adsorption of red 40 dye on rice husk: determination of the equilibrium, kinetic and thermodynamic of the process
| Autor: | Fredy Alberto Amaringo Villa, Angelina Del Socorro Hormaza Anaguano |
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| Jazyk: | Spanish; Castilian |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Tecnura, Vol 22, Iss 56, Pp 13-28 (2018) |
| Druh dokumentu: | article |
| ISSN: | 0123-921X 2248-7638 22487638 |
| DOI: | 10.14483/22487638.12961 |
| Popis: | Context: Agricultural residues have become unconventional adsorbents of great interest due to their wide availability, minimum cost, and high efficiency. In this work, the adsorbent capacity of rice husk by-product (RH) in the Red 40 (R40) anionic dye removal was evaluated under a discontinuous system. Method: For determining the best conditions for the removal of this dye, a factorial design 23 was implemented, which allows to achieving a removal of 75.6% at pH = 2.0, an initial concentration of 15 mg/L, dosage of 8.0 g/L, and contact time of 18 hours. Results: The equilibrium, kinetics and thermodynamic properties of the process were evaluated. It was found that the Langmuir model best represents the experimental results with qmax of 2.74 mg/g and an adjustment coefficient of R2=0.987. Regarding kinetics, the pseudosecond order model with qt of 1.09 mg/g presented the best fit (R2 = 0.970). Finally, Gibbs free energy (ΔG = -1.11 KJ/mol) and entropy (ΔS = 23.9 J/mol*K) indicate a spontaneous process, while enthalpy showed that the removal of R40 constitutes an endothermic process, with ΔH = 6.71 KJ/mol. Furthermore, the activation energy of 14.1 KJ/mol suggests that the mechanism of adsorption of the R40 takes place through a physi-adsorption. Conclusions: These results indicate that the rice husk offers a adequate adsorbent capacity for the retention of azo dye off contaminated effluents; besides, scaling up this process is feasible given its thermodynamic characteristics. |
| Databáze: | Directory of Open Access Journals |
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