Ion Flotation of Ytterbium Water-Salt Systems—An Innovative Aspect of the Modern Industry

Considering the ever-increasing role of rare-earth elements (REE) in the modern hi-tech field, their effective use has tremendous significance, although the production process is inevitably linked to the large volumes of industrial ammonia effluents and heavy metal wastes. In the process of metallurgical separation of metals, the emission of large volumes of noxious gases and radioactive substances is inevitable. Lean technogenic raw material processing is sensible under the condition of the development of non-waste technology. The lack of competent regulations governing the disposal of waste containing REE has an impact on adjacent territories, accumulating in water bodies and, as a result, in the human body. Such an impact cannot pass without a trace, however, the ambiguity of opinions in the scientific community regarding the toxic effects of REE on living organisms determines the relevance of a more detailed study of this issue. The study of ytterbium ions removal from aqueous standard test solutions by the adsorptive bubble method—ion flotation—was conducted. The experiments showed that by using the ion flotation method, the maximum removal of ytterbium (III) was achieved at pH = 8.30. It was shown that ytterbium (+3) distribution coefficients as a function of aqueous phase pH value in the process of ion flotation with sodium dodecyl sulphate were derived. The comparison of values of removal pH with those of hydrate formation pH allowed to conclude that ytterbium floate as basic dihydroxoytterbium dodecyl sulphate Yb(OH)2(C12H25OSO3).

The Removal of Rare-Earth Metals from Water-Salt Systems – An Innovative Aspect of the Modern Industry

Considering the ever-increasing role of rare-earth elements (REE) in the modern hi-tech field, their effective use has a tremendous significance, although the production process is inevitably linked to the large volumes of industrial ammonia effluents and heavy metal wastes. In the process of metallurgical separation of metals, the emission of large volumes of noxious gases and radioactive substances is inevitable. Lean technogenic raw material processing is sensible under the condition of the development of non-waste technology. The lack of competent regulations governing the disposal of waste containing REE has an impact on adjacent territories, accumulating in water bodies and, as a result, in the human body. Such an impact cannot pass without a trace, however, the ambiguity of opinions in the scientific community regarding the toxic effects of REE on living organisms determines the relevance of a more detailed study of this issue. The paper presents experimental and theoretical results of studies of ion flotation in the aqueous solutions containing ytterbium cations and a surfactant as a collector - sodium dodecyl sulphate (NaDS).

Cr(III) and Ni(II) Complexes of Isatin-hydrazone Ligand: Preparation, Characterization, Dft Studies, Biological Activity, and Ion-Flotation Separation of Ni(II)

In the current work, a ligand N'1-((E)-2-hydroxy-3H-indol-3-ylidene)-N'3-((E)-2-oxoindolin-3-ylidene)malonohydrazide (H4MDI) and its Cr(III) and Ni(II) complexes have been synthesized and characterized by various conventional methods. For evaluating the optimal ligand structure and its complexes, calculations of DFT were applied. Magnetic measurements inherent to their electronic spectra show that both Cr(III) and Ni(II) chelates have octahedron coordination frameworks. On the other hand, the IR spectral data revealed that the ligand behaves as a binegtive hexadentate in [Cr2(H2MDI)(H2O)2Cl4] and as a tetranegative hexadentate in [Ni2(MDI)(H2O)6].4H2O. In addition, the behavior of thermal decomposition for prepared complexes was discussed. Two comparable methods (Coats-Redfern and Horowitz-Metzger) were used to calculate the kinetic parameters of the resulted thermal decomposition stages. Furthermore, the ion-flotation process was used for the separation of Ni(II) from aqueous media via the prepared ligand as a chelating agent and oleic acid as a surfactant. Moreover, the antimicrobial behavior of the synthesized moieties was investigated against various bacterial and fungal strains. H4MDI has the most activity with minimum inhibitory concentration (MIC) of 0.78 µg/mL for both E. coli, and C. Albicans, while Ni(II) complex shows the activity against S. aureus, E. coli, and C. Albicans with MIC of 2.34, 4.68, and 1.17 µg/mL, respectively. Finally, the in-vitro cytotoxic activity of the prepared compounds against hepatocellular carcinoma human tumor cells (HePG-2) has been examined, and revealed that H4MDI and its Ni(II) complex show very strong activity against HePG-2 with IC50 of 9.7 and 7.7 µmol/L, respectively.