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    Cloud Point Extraction and Flame Atomic Absorption Spectrometric Determination of Cd(II) in Industrial and Environmental Samples
    (Maik Nauka/Interperiodica/Springer, 2018) Surme, Y.; Bisgin, A. T.; Ucan, M.; Narin, I.
    A micelle-mediated separation/preconcentration technique was used for the determination of trace Cd(II) in solid and liquid samples by flame atomic absorption spectrometry. Cadmium ions reacted with ammonium pyrrolidine dithiocarbamate to form a chelate that was extracted from aqueous medium by a non-ionic surfactant Tergitol NP-7 at pH 7. Values of pH, concentrations of ammonium pyrrolidine dithiocarbamate and Tergitol NP-7, temperature, incubation time, sample volume and matrix ions were optimized. The enrichment factor of the method was found to be 25, and the detection and quantitation limits were 1.5 and 3.8 mu g/L, respectively. Assessment of the method was performed with a certified reference material, and the observed concentration of Cd(II) was in good agreement with the certified value. The method was also applied to the determination of Cd(II) in waters and industrial samples. Cd(II) concentrations in two industrial ZnO composite samples were determined between 59 and 69 mu g/g.
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    Role of polyethylene glycol tert-octylphenyl ether on corrosion behaviour of mild steel in acidic solution
    (TAYLOR & FRANCIS LTD, 2009) Surme, Y.; Gurten, A. Ali
    In recent years, polymeric surfactants have been investigated as efficient corrosion inhibitors for iron in acidic media. In this study, the inhibition performance of polyethylene glycol tert-octylphenyl ether (Triton X-114) for the corrosion of iron in 1M HCl solution has been evaluated. Potentiodynamic polarisation, electrochemical impedance spectroscopy, linear polarisation resistance techniques and long term experiments were used to achieve electrochemical studies. The effect of polyethylene glycol tert-octylphenyl ether on cathodic hydrogen evolution reaction was also investigated. The inhibition efficiency has increased with increasing inhibitor concentration. The standard free energy of adsorption (Delta G degrees(ads)) was calculated. The inhibitor adsorbed on the iron surface was found to be in a good agreement with the Langmuir adsorption isotherm. Polyethylene glycol tert-octylphenyl ether has improved the passivation characteristics of mild steel and inhibited the corrosion effectively in short time tests. The corrosion behaviour of mild steel was also supported by micrographing of the iron surfaces in 1M HCl solution with or without inhibitor.
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    Separation, Preconcentration and Spectrophotometric Determination of Rhodamine B in Industrial, Cosmetic and Water Samples by Cloud Point and Solid Phase Extraction
    (Maik Nauka/Interperiodica/Springer, 2018) Bisgin, A. T.; Surme, Y.; Ucan, M.; Narin, I.
    The aim of this study is extraction, preconcentration and spectrophotometric determination of Rhodamine B (RB) in aqueous media by developing solid phase extraction (SPE) and cloud point extraction (CPE) methods. Amberlite XAD-1180 adsorbent and Tergitol NP-7 surfactant were used for SPE and CPE, respectively. Parameters of SPE and CPE which effected quantitative extractions were investigated and optimized. Matrix effects of some ions and dyes were analyzed at the optimum conditions. Developed methods were used to determine RB contents of anti-freeze, lipstick and water samples. The results of both methods demonstrated that the RB was quantitatively extracted and determined. RB contents of solid samples were found between 473 +/- 15 and 317 +/- 8 mu g/g; 472 +/- 11 and 312 +/- 6 mu g/L dye contents were determined for liquid samples. The methods were tested by analysis of spiked samples. Analytical characteristics of the methods were compared with each other and previously reported studies.
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    Thermo-electrical properties in Pb-Sb hypereutectic alloy
    (KOREAN INST METALS MATERIALS, 2013) Sahin, M.; Cadirli, E.; Surme, Y.; Ozkir, D.
    Pb-17 wt% Sb hypereutectic alloy was directionally solidified upward with three different growth rates (8 mu m/s, 18 mu m/s, 42 mu m/s, 166 mu m/s and 497 mu m/s) at a constant temperature gradient (3.6 K/mm) in the Bridgman-type growth apparatus. The dependence of characteristic microstructure parameters such as primary dendrite arm spacing (lambda(1)) and secondary dendrite arm spacing (lambda(2)) on the growth rate (V) were determined by using a linear regression analysis. Variations of electrical resistivity (rho) for cast samples for temperatures in the range of 300-550 K were measured by using a standard dc four-point probe technique. The variations of thermal conductivity with temperature for the same alloys were determined from the WiedemannFranz and SmithPalmer equations by using the measured values of electrical resistivity. The enthalpy of fusion for the same alloys were determined by means of a differential scanning calorimeter from a heating trace during the transformation from solid to liquid. The corrosion resistance was analyzed by Tafel extrapolation and linear polarization resistance methods conducted in a 5% sodium chloride solution in contact with air maintained at room temperature. Effects of the growth rate on the electrical resistivity and corrosion resistance were also investigated.