| Abstrakt: |
The adsorption of Ni(II), Zn(II), and Cu(II) ions by electrogenerated gibbsite (γ-modification aluminum hydroxide) has been studied. Electrically generated gibbsite was obtained by electrolysis of aqueous solutions using aluminum electrodes. We used gibbsite obtained during the first 5 min of electrolysis. Such an adsorbent has an amorphous state and a network structure and, as a consequence, has good adsorption capacity. The adsorption value for Ni(II) ions was 437.0 mg/g; for Zn(II), 362.5 mg/g; and for Cu(II), 148.8 mg/g. The obtained isotherms have a stepwise character, which is explained by the inhomogeneity of the adsorbing surface, on which there are groups of active centers that differ sharply from each other in their activity. The adsorption of toxic ions was studied using the Langmuir, Freundlich, and Dubinin–Radushkevich models. The values of the correlation coefficients indicate that the adsorption of Zn(II) Cu(II) ions is best described by the Langmuir model, and the adsorption of Ni(II) ions, by the Dubinin–Radushkevich model. On the basis of the Dubinin–Radushkevich adsorption model, the values of the free adsorption energy are determined, which indicate the physical nature of the interaction between the adsorptive and the adsorbent. The adsorption of toxic ions on the gibbsite surface occurs mainly due to dispersion interaction. [ABSTRACT FROM AUTHOR] |
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