Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology

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Start date: 2024Subject: search.filters.subject.adsorption

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    Using of waste sorbent from food industry for the removal of copper ions from water [Articol]
    (2025) Khudoiarova, Olha; Blazhko, Oleg; Blazhko, Alina
    The purpose of the work was to investigate the effectiveness of using a previously regenerated spent food industry sorbent modified with sulphide and hydrosulphide ions for the removal of copper(II) ions from water. A comparative analysis of the degree of removal and adsorption of copper(II) ions by the regenerated sorbent (RS) and its modified form (MS) was carried out. Insignificant adsorption of Cu2+ on the surface of the RS is explained both by the nature of the adsorbate and the morphology of the adsorbent after its acid-alkaline activation. Modification of the surface of the regenerated sorbent with more active sulphide and hydrosulphide ions leads to an increase in the removal of copper(II) cations from the studied solutions by 65.5 times. IR-spectroscopy and X-ray phase analysis have shown that topochemical reactions occur on the surface of the MS, leading to the formation of copper(II) sulphide CuS and elemental sulphur. The obtained results allow us to recommend the use of a RS of the food industry, modified with sulphide and hydrosulphide ions, to remove copper(II) ions from water.
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    Insights on metal doped graphene in the adsorption of arsenic Via dft calculation [Articol]
    (2025) Ayeni, Ibraheem Olusola; Oyegoke, Toyese
    Arsenic contamination in drinking water poses significant health risks worldwide, making the development of efficient removal technologies a critical area of research. This study explores the enhancement of graphene’s arsenic (As) adsorption capabilities through metal doping at various positions on its surface. Using density functional theory, the interactions between arsenic and graphene doped with selected metals were simulated, evaluating the influence of different doping positions on adsorption efficiency. The results demonstrated that metal doping significantly improves the arsenic removal capacity of graphene, with variations observed depending on the doping configuration. These findings contribute to a deeper understanding of the adsorption mechanisms in graphene-based materials and offer a computational approach for designing advanced adsorbents for environmental remediation.
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    Preparation and characterization of biochar-iron oxide-palygorskite composites for uranium(VI) removal from aqueous solutions [Articol]
    (2025) Pylypenko, Ihor; Kovalchuk, Iryna; Tsyba, Mykola; Lytvynenko, Yurii; Shyrokov, Oleksandr
    This paper details the synthesis of palygorskite/biochar/iron oxide composites and their utilization for the remediation of water solutions contaminated with uranium(VI). The synthesis procedure involved the combination of iron chloride, starch, and palygorskite with subsequent pH adjustment, drying of the formed precipitate, and pyrolysis at 600°C. The synthesis of mesoporous materials, primarily composed of iron oxides, including magnetite and hematite, was confirmed using various characterization techniques, including FTIR, SEM, and XRD. It was shown that the adsorption of uranium(VI) reached a maximum of 100.2 μmol/g, exhibiting the highest affinity, which is associated with significant magnetite involvement, which facilitates the reduction processes of uranium(VI) to uranium(IV). The findings demonstrated that the uranium removal process was enhanced by a rise in pH, with significant adsorption and possible precipitation occurring under neutral conditions, so using these composite materials is suitable for in situ remediation of water solutions contaminated by uranium(VI).
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    Spectroscopic properties of ZnPc(COOH)4/Ch/Fe3O4 supramolecular architectures [Articol]
    (CEP USM, 2024) Druță, Alexandrina; Lungu, Ion; Popușoi, Ana; Potlog, Tamara; Bulmaga, Petru; Rusnac, Roman
    This paper presents the synthesis of ZnPc(COOH)4/Ch/Fe3O4 supramolecular architectures at various ZnPc(COOH)4 and Ch/Fe3O4 concentrations explored in the synthesis process. Ch/Fe3O4 composite was prepared by a simple solution mixing-evaporation method. The validation of the synthesis was achieved through FTIR analysis and UV-Vis spectroscopy. FTIR of composite indicated an interaction between chitosan and Fe3O4 NPs. The chemical interaction of ZnPc(COOH)4 with Ch/F3O4 composite is confirmed by the shift of the signal from ν(C=O)) of protonated COOH groups in the FTIR spectrum of ZnPc(COOH)4, associated with spitting, to (νsym(COO)) and (νasym(COO)) that correspond to deprotonated carboxylic group. The absorption spectra of ZnPc(COOH)₄ revealed IR Q band with two subbands situated at 640 nm 700 nm. Also, the effect of various ZnPc(COOH) and Ch/Fe3O4 concentrations on absorbance of ZnPc(COOH)4/Ch/Fe3O4 supramolecular architecture is discussed.