The interaction of methylene blue (MB) dye with natural coal (collected from coal landfills of the Kosovo Energy Corporation) in aqueous solutions was studied using adsorption, kinetics, and thermodynamic data, and Monte Carlo (MC) calculations. In a batch procedure, the effects of contact duration, initial MB concentration, pH, and solution temperature on the adsorption process were examined. The Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) isotherms were used to examine the equilibrium adsorption data. The equilibrium data fit well to the Freundlich and Langmuir adsorption isotherm models; however, the Freundlich model suited the adsorption data to a slightly better extent than the Langmuir model. The kinetics experimental data was fitted using pseudo-first-order, first-order, pseudo-second-order, second-order, Elvoich equation, and diffusion models. The pseudo-second-order rate model manifested a superlative fit to the experimental data, while the adsorption of MB onto coal is regulated by both liquid film and intraparticle diffusions at the same time. Thermodynamic parameters, such as Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were calculated. The adsorption of MB was confirmed to be spontaneous and endothermic. The theoretical results were in agreement with the experimental ones.
Five novel pyrazolylnucleosides have been evaluated theoretically for their corrosion inhibition efficiency on the Cu(111) surface in acidic media. DFT calculations were carried out to exhibit the intrinsic properties such as lowest unoccupied (ELUMO) and highest occupied (EHOMO) molecular orbital energies, as well as energy gap (∆E), chemical hardness (η), chemical softness (σ), electronegativity (χ), electrophilicity (ω) and nucleophilicity (ε). The theoretical FT-IR spectra were recorded to indicate the presence of the specific bonds in the studied molecules. The surface interactions between the inhibitor molecules and the metal surface were investigated using molecular dynamics simulations and Monte Carlo (MC) simulations. As a result, we have found that the inhibitor pyrazolylnucleosides 5a–e have strong interactions with Cu(111) surface, and therefore have excellent predictive inhibition power against copper corrosion.
Contamination of soil and water by various heavy metals such as Cd, Pb, Ni, Cu, and Fe is increasing day by day as a result of different activities, such as industrialization and urbanization. Lead (Pb), Cadmium (Cd), and Nickel (Ni) are examples of potential heavy metals that are neither essential elements nor have any role in the process of cell metabolism, but are easily absorbed and accumulated in different parts of a plant and living beings. This study was to investigate the translocation and bioaccumulation of heavy metals such as Pb, Ni, Cd, Cu, and Fe in Urtica dionica L and soil samples from 2 sites (uncontaminated-Koliq and contaminated-Kishnica in the Republic of Kosovo). The results revealed that in the contaminated site, the mean level of all the metals in soil and different parts (root, stalk, and leaf) of the plant were found to be significantly (p<0.01) higher than the uncontaminated site. Multivariate analysis was used to determine the distribution of metals within the study area. The trace metal contents from different parts of these plants were determined by the use of AAS. The results revealed that Urtica dionica L. translocated high amounts of metals to its organs, especially to leaves, so that translocation factors were much higher than one (>1). However, these concentrations of heavy metals in the soil and Urtica dionica L were higher than levels specified according to the standards in UK and Germany.
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