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.

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) is an example of potential heavy metal that is neither an...

The major goal of this research was to employ honey as a bio indicator to identify heavy metal levels in bee honey in the Istog, Drenas, and Kastriot regions. As a result, honey was purposely tested in these locations, and two industrial specific areas were chosen for examination and analysis:...

For more than five decades, dithizone has been widely used as an analytical reagent. This ligand forms strongly colored complexes with metal ions and this ability to form complexes can be used for extraction/removal of certain metal ions in addition to analytical determination. In static mode, the supercritical carbon dioxide extraction of copper and lead ions from aqueous solutions after complexation by the dithizone ligand is studied (at two different conditions: a) p = 120 bar, T = 30 °C, and b) p = 72 bar, T = 50 °C). The addition of methanol improved the extraction process by modulating the polarity of the extraction medium. Atomic absorption spectroscopy (AAS) is used to determine the concentration of metal ions before and after extraction. We use density functional theory (DFT) [model chemistry: using m-GGA/M11-L] to better understand the binding energy and geometry of bidentate ligands produced from dithizone and copper(II) or lead(II) ions. Furthermore, the developed complexes? noncovalent interactions (NCI), bond order analysis, and electron localization function (ELF) provided valuable details about these molecules. To elucidate the bidentate complex extraction mechanism formed between the heavy metal ions and the dithizone ligand, molecular dynamic simulations at periodical boundary conditions were performed using the universal force field to obtain precise molecular descriptions.

Metal ions in liquid samples can be extracted by supercritical CO 2 , containing a suitable ligand. This paper presents the first experimental data for the extraction of three heavy metals Cu, Zn and Cd from aqueous samples in the presence of Dithizone as chelating agent. Extractions by supercritical CO 2 have been performed at 120 bars with 50°C used dynamic technique. After adding the CO 2 on the aqueous metal solution, the pressure and temperature were set and extraction was performed in three periodical times; 30, 60 and 120 min at constant temperature and pressure with a flow rate of CO 2 2 mL min-1. After the extraction, the CO 2 was released slowly through a restrictor. Methanol was used as a modifier (v/v) 10% and the pH value was set (10). After the extraction process, the remaining aqueous solution in the extractor was analyzed for its metal content by Atomic Absorption Spectrophotometer (AAS), determining the recovery of the metal by CO 2. During dynamic extraction noticed increased of extraction in function of time for all three metals; Cu (61.12-73.52%, RSD = 2.694, n = 3); Zn (78.33-87.00%, RSD = 1.243, n = 3) and Cd (70.60-82.40%, RSD = 2.227, n = 3).

It is presently well-recognized that the contamination of aquatic sediments in Kosovo is a widespread phenomenon. The observation of the chemical analysis of water and sediments is essential to determine the extent of trace elements in these ecosystems. Hence, in order to be able to determine the...