Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - Scopus: 7
    Modification of Grape Pulp With Citric Acid for the Production of Natural Ion Exchanger Resin and Removal of Pb (ii) and Cd (ii) From Aqueous Solutions: Kinetic, Thermodynamics, and Mechanism
    (Springer Science and Business Media Deutschland GmbH, 2023) Arslanoğlu, E.; Eren, M.Ş.A.; Arslanoğlu, H.; Çiftçi, H.
    In this study, grape pulp (MGP) modified with NaOH and citric acid was used in the production of natural ion exchangers. The effects of parameters such as initial pH, MGP dosage, temperature, initial metal ion concentration, and contact time on the removal of Pb (II) and Cd (II) ions from aqueous solutions using modified materials were investigated by batch experiments. It was found that the experimental kinetic data fit the second-order model, and the activation energy for Pb (II) and Cd (II) adsorption processes were 20.68 and 38.61 kj mol−1, respectively. Although the initial adsorption rate increases with increasing temperature, the adsorption efficiency slightly decreases. It was calculated that the equilibrium data fit the Langmuir isotherm better, and the maximum adsorption capacities for Pb (II) and Cd (II) adsorption processes were approximately 1.496 and 1.022 mmol g−1 at 25 °C, respectively. Thermodynamic analysis has shown that the adsorption processes of Pb (II) and Cd (II) are exothermic (ΔH°Pb = −35.68 kj mol−1, ΔH°Cd = −21.19 kj mol−1) and have a self-developing character. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
  • Article
    Citation - Scopus: 1
    Assessment and Transport of Sediment-Bound Estuarine Contaminants
    (Springer, 2015) Work, P. A.; Haas, K. A.; Warren, D. A.; Elçi, Şebnem
    Estuaries and coastal bays frequently receive anthropogenically sourced contaminants. Many of these contaminants (e.g. most metals) have low solubility and tend to sorb to sediment particles, so that sediment transport driven by fluid mechanics becomes an important part of the contaminant transport problem. The chosen strategy for mitigation of the contaminant(s) will depend on the potential for migration away from the affected region, or the build-up of concentrations within the receiving area if loading rate exceeds decay or transport rates, and the potential impact on environmental and human health both within and outside the receiving area. Two case studies are considered here in which data describing instantaneous contaminant concentrations in estuarine environments were acquired via field sampling. Both sites feature estuaries dominated by tidal forcing, with smaller, adjacent upland regions also impacted. Metals, particularly copper and lead, are the primary focus in each case. Contaminant transport processes, including diffusion, advection, and bioturbation, are treated together to develop analytical and numerical solutions for time-dependent contaminant concentrations using a spatially varying, time-dependent, effective diffusion coefficient that is influenced by local surface water flow speeds. Different initial, boundary, and loading conditions are considered to illustrate the relative importance of the various transport processes. Implications of future contaminant loading and sea level rise scenarios are demonstrated and discussed.
  • Article
    Citation - WoS: 28
    Citation - Scopus: 29
    Oxidation of Nanocrystalline Aluminum by Variable Charge Molecular Dynamics
    (Elsevier Ltd., 2010) Perron, A.; Garruchet, S.; Politano, O.; Aral, Gürcan; Vignal, V.
    We investigate the oxidation of nanocrystalline aluminum surfaces using molecular dynamics (MD) simulations with the variable charge model that allows charge dynamically transfer among atoms. The interaction potential between atoms is described by the electrostatic plus (Es+) potential model, which is composed of an embedded atom method potential and an electrostatic term. The simulations were performed from 300 to 750 K on polycrystalline samples with a mean grain size of 5 nanometers. We mainly focused on the effect of the temperature parameter on the oxidation kinetic. The results show that, beyond a first linear regime, the kinetics follows a direct logarithmic law (governed by diffusion process) and tends to a limiting value corresponding to a thickness of similar to 3 nm. We also characterized at 600 K the effects of an external applied strain on the microstructure and the chemical composition of oxide films formed at the surface. In particular, we obtained a partially crystalline oxide films for all temperatures and we noticed a strong correlation between the degree of crystallinity of the oxide film and the oxidation temperature. (C) 2009 Elsevier Ltd. All rights reserved.