Yazar "Katin, K. P." seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    Comparison of traditional and fullerene-based adsorbents for extraction of 1,4-dioxane and 2-methyl-1,3-dioxolane from milk
    (Russian Acad Sciences, Inst Metals Superplasticity Problems, 2021) Kochaev, A., I; Razavi, R.; Kaya, S.; Mogaddam, M. R. A.; Altunay, N.; Nemati, M.; Katin, K. P.
    Using density functional methods, the results of the analysis of traditional adsorbents and adsorbents based on nanosized particles capable of trapping 1,4-dioxane and 2-methyl-1,3-dioxolane molecules in milk are presented. We considered the following interacting compounds: 1,4-dioxane - primary amine, 1,4-dioxane - secondary amine, 1,4-dioxane - fullerene C-20, 1,4-dioxane-a fragment of the structure of activated carbon, 2-methyl-1,3-dioxolane - primary amine, 2-methyl-1,3-dioxolane-secondary amine, 2-methyl-1,3-dioxolane - fullerene C-20, 2-methyl-1,3-dioxolane - a fragment of the structure of activated carbon. We determined the optimal configurations of the corresponding interacting structures, estimated their binding energies and chemical potentials. The highest binding energy was obtained for 1,4-dioxane adsorbed on C-20 fullerene. At the same time, the energy gaps between the occupied HOMO and unoccupied LUMO molecular states were calculated, which makes it possible to characterize the reactivity and stability of molecules. Compounds of 1,4-dioxane and 2-methyl-1,3-dioxolane with amines have rather large gaps HOMO-LUMO. Using the concept of the electronic localization function, we found that a covalent bond is formed between 1,4-dioxane and C-20 fullerene with a sufficiently high degree of electron localization in the bond region. In other cases, the value of the localization function indicates the absence of a chemical bond between the compounds. The proposed study gives recommendations on the adsorption of 1,4-dioxane and 2-methyl-1,3-dioxolane for further solid-phase microextraction, which will allow them to be found in milk by gas chromatography using a flame ionization detector.
  • Küçük Resim Yok
    Öğe
    Development of sensitive and accurate solid-phase microextraction procedure for preconcentration of As(III) ions in real samples
    (Nature Portfolio, 2021) Elik, Adil; Tuzen, Mustafa; Hazer, Baki; Kaya, Savas; Katin, K. P.; Altunay, Nail
    We synthesized the poly(methyl methacrylate-co-2-aminoethyl methacrylate (PMaema) amphiphilic copolymer in a form of solid phase adsorbent. Then it was used for separation, preconcentration and determination of trace amount of As(III) ions from foods and waters with hydride generation atomic absorption spectrometry. The PMaema was characterized by fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The adsorption of As(III) to the PMaema was also supported using computational chemistry studies. The experimental parameters (pH, PMaema amount, adsorption time and ethanol volume) were optimized using a three-level Box-Behnken design with four experimental factors. We observed linear calibration curve for the PMaema amount in the 10-500 ng L-1 range (R-2=0.9956). Limit of detection, preconcentration factor and sorbent capacity of PMaema were equal to 3.3 ng L-1, 100 and 75.8 mg g(-1), respectively. The average recoveries (spiked at 50 ng L-1) changes in the range of 91.5-98.6% with acceptable relative standard deviation less than 4.3%. After validation studies, the method was successfully applied for separation, preconcentration and determination of trace amount of As(III) from foods and waters.
  • Küçük Resim Yok
    Öğe
    Graphene nanoflakes and fullerenes doped with aluminum: features of Al-C interaction and adsorption characteristics of carbon shell
    (Russian Acad Sciences, Inst Metals Superplasticity Problems, 2022) Katin, K. P.; Kaya, S.; Maslov, M. M.
    The aluminium-carbon interaction in two core-shell systems (Al-22 nanoparticle coated with graphene nanoflake and Al@C-60 metallofullerene) is investigated within the density functional theory. A set of non-equilibrium configurations of the coated Al-22 nanoparticle is obtained from the ab initio molecular dynamics simulation. The Morse parameters describing the Al-C interaction are fitted based on density functional calculations performed at the B3LYP/6-31G* level of theory. The Grimme's D3 dispersion corrections are added to accurately account for the non-covalent interactions. it is shown that the concave carbon surface interacts much weaker with the nanoparticle and is located further away from it compared to the usually considered convex surfaces. Negligible charge transfer from aluminum core to carbon shell confirms that Al-22 nanoparticle do not change the shell reactivity. in contrast, a single Al atom endohedrally doped C-60 fullerene strongly interacts with the carbon cage and distorts the frontier molecular orbitals and reactivity of the compound. We also compare the hydrogen F..H-O bonds formed between the fluorinated C60F2 or Al@C60F2 cages and niacin drug molecule. We found that Al leads to drastic weakening of this hydrogen bond. We conclude that Al-22 nanoparticle do not change reactivity of the carbon shell, whereas a single Al atom reduces reactivity of the outer fullerene.
  • Küçük Resim Yok
    Öğe
    Synthesis of carbon modified with polymer of diethylenetriamine and trimesoyl chloride for the dual removal of Hg (II) and methyl mercury ([CH3Hg]+) from wastewater: Theoretical and experimental analyses
    (Elsevier Science Sa, 2022) Tuzen, Mustafa; Sari, Ahmet; Mogaddam, Mohammad Reza Afshar; Kaya, Savas; Katin, K. P.; Altunay, Nail
    A novel adsorbent was synthesized by modification of waste rubber tiers derived activated carbon (AC) with diethylenetriamine (DETA)-trimesoyl chloride (TMC) copolymer. The synthesized AC/DETA-TMC nanocomposite was characterized by FT-IR and SEM/EDX techniques. Dependency of the adsorption yield on the batch parameters was studied via factorial design method. From the non-linear Langmuir isotherm model, the adsorption capacity of the AC/DETA-TMC nanocomposite was determined as 317.3 and 263.6 mg g 1 for inorganic mercury (Hg2+) and organic mercury (methyl mercury; [CH3Hg]+, respectively. The adsorption kinetic mechanism of both mercury species was recognized well by the PSO model. The thermodynamic calculations verified that the adsorption processes progressed spontaneously and exothermically. The cycling adsorption/ desorption treatments exposed that the produced nanocomposite showed still reusable performance in moderate level until seven cycles. The nanocomposite demonstrated high removal performance in case of wastewater samples. To investigate the power of the interactions between studied chemical species, DFT calculations were performed and adsorption energies were calculated. It is important to note that theoretical results support the experiments made.