Yazar "Bahadir, Muefit" seçeneğine göre listele

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    Application of simple and low-cost toxicity tests for ecotoxicological assessment of industrial wastewaters
    (TAYLOR & FRANCIS LTD, 2015) Aydin, Mehmet Emin; Aydin, Senar; Tongur, Sueheyla; Kara, Gulnihal; Kolb, Marit; Bahadir, Muefit
    The objective of this study was to identify and to apply appropriate biotests having the advantages of being highly sensitive, easy to run, relatively inexpensive and able to substitute fish toxicity tests due to ethical reasons of animal welfare. To perform an ecotoxicological assessment of industrial wastewaters, different microbiotests were conducted to substitute the fish toxicity test with Lebistes reticulatus through Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, Lemna minor and Lepidium sativum representing different trophic levels in the aquatic and terrestrial ecosystems. Also, Algaltox F-TM with Pseudokirchneriella subcapitata and Protox F-TM with Tetrahymena thermophila tests were carried out. However, they could not be applied successfully for the wastewater samples. Wastewater samples from seven different industrial zones comprising different industries were subjected to characterization through measuring their physical-chemical parameters and their toxicity versus the above-mentioned organisms. T. platyurus, D. magna and L. reticulatus were the most sensitive test organisms investigated for the wastewaters. Considering toxic unit values, generally wastewater samples were toxic according to Thamnotox F-TM, Daphtox F-TM and fish toxicity tests. As an important outcome, it was concluded that Daphtox F-TM and Thamnotox F-TM could be a good alternative for the fish toxicity test, which is so far the sole toxicity test accepted by the Turkish Water Pollution Control Regulation.
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    Removal of arsenic (V) from aqueous medium using manganese oxide coated lignocellulose/silica adsorbents
    (TAYLOR & FRANCIS LTD, 2016) Ouedraogo, Igor W. K.; Pehlivan, Erol; Tran, Hien T.; Pare, Samuel; Bonzi-Coulibaly, Yvonne L.; Zachmann, Dieter; Bahadir, Muefit
    Arsenic (V) adsorption on manganese oxide coated rice wastes was investigated in this study. The modified adsorbents were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and pH measurements to determine the point of zero charge. Batch adsorption equilibrium experiments were conducted to study the effects of pH, contact time, and initial concentration on arsenic removal efficiency. The adsorption capacity of rice waste was significantly improved after modification with permanganate. The Langmuir isotherm model fitted the equilibrium data better than the Freundlich model which confirms surface homogeneity of the adsorbent. Maxima adsorption capacities are determined as 10 and 12 mg/g at pH 3 for manganese oxide coated rice husk and straw, respectively. The adsorption energy indicates that the adsorption process may be dominated by chemisorption. Pseudo-second-order rate equation described the kinetics sorption of arsenic with good correlation coefficients, better than a pseudo-first-order equation. Manganese oxide coated rice husk and straw appear to be promising low cost adsorbents for removing arsenic from water.
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    Synthesis of iron oxyhydroxide-coated rice straw (IOC-RS) and its application in arsenic(V) removal from water
    (IWA PUBLISHING, 2015) Ouedraogo, Igor W. K.; Pehlivan, Erol; Tran, Hien T.; Bonzi-Coulibaly, Yvonne L.; Zachmann, Dieter; Bahadir, Muefit
    Because of the recognition that arsenic (As) at low concentrations in drinking water causes severe health effects, the technologies of As removal have become increasingly important. In this study, a simplified and effective method was used to immobilize iron oxyhydroxide onto a pretreated naturally occurring rice straw (RS). The modified RS adsorbent was characterized, using scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and surface area analyzer. Experimental batch data of As(V) adsorption were modeled by the isotherms and kinetics models. Although all isotherms, the Langmuir model fitted the equilibrium data better than Freundlich and Dubinin-Radushkevich models and confirmed the surface homogeneity of adsorbent. The iron oxyhydroxide-coated rice straw (IOC-RS) was found to be effective for the removal of As(V) with 98.5% sorption efficiency at a concentration of <50 mg/L of As(V) solution, and thus maximum uptake capacity is similar to 22 and 20 mg As(V)/g of IOC-RS at pH 4 and 6, respectively. The present study might provide new avenues to achieve the As concentrations required for drinking water recommended by the World Health Organization.
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    TOXICITY ASSESSMENT OF LANDFILL LEACHATES WITH A BATTERY OF BIOASSAYS
    (PARLAR SCIENTIFIC PUBLICATIONS (P S P), 2015) Aydin, Mehmet Emin; Aydin, Senar; Bahadir, Muefit; Kolb, Marit; Tongur, Suheyla; Kara, Gulnihal
    In this study, the toxicity of the leachate from the municipal landfill was evaluated and assigned to its chemical composition. Leachate samples were collected considering different seasons and assessed for their toxicity by using Thamnotox with Thamnocephalus platyurus, Daphtox with Daphnia magna, Vibrio fischeri, Lemna minor, and Lepidium sativum. Leachate samples were also characterized measuring their physical and chemical parameters. Relationships between the chemical composition and the toxicity of leachate samples were established. EC50, values for Thamnotox, Lemna minor, and Lepidium sativum were negatively correlated with the COD content. There were significant correlations between the TOC with EC50 values of Vibrio fischeri and Lemna minor tests. Vibrio fischeri wasthe most sensitive test organism investigated for the landfill leachate. Considering toxic unit values, leachate samples were highly to very highly acute toxic, according to all the tests carried out.