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Biosorption of astrazon red dye by the bacterium Rhodopseudomonas sp. strain 51ATA
(Springer, 2021) Abdullah, Meysun I.; ozturk, Ayten; Bayol, Emel
Astrazon red azodye that is still widely used in Turkey is released into the aquatic environment. Since these dyes are degradable into the toxic aromatic amines, they have become a public health and environmental concern. In this study, the biosorption of the Astrazon red dye from aqueous solutions on dehydrated cells of Rhodopseudomonas sp. 51ATA was studied as a function of each pH, temperature and initial dye concentration. Rhodopseudomons sp. 51ATA strain belongs to the Rhodopseudomonas species which is an eco-friendly photosynthetic and facultative anaerobic bacterium. The best uptake of Astrazon red was observed at pH 2.0 and the data obtained were applied to both Freundlich and Langmuir adsorption isotherms. The adsorption data provided an excellent fit to both isotherms and showed good agreement to Scatchard analysis at various temperatures. Freundlich isotherm showed good fit to the data at low temperatures while Langmuir model was suitable for describing the adsorption at higher temperatures. Therefore, from these data, we could report that Rhodopseudomonas sp. 51ATA strain is very efficient bacterium for the removal of dyes from wastewater.
Characterization of the biosorption of fast black azo dye K salt by the bacterium Rhodopseudomonas palustris 51ATA strain
(Univ Catolica De Valparaiso, 2020) Ozturk, Ayten; Bayol, Emel; Abdullah, Meysun, I
Background: Removal of dyes from wastewater by microorganisms through adsorption, degradation, or accumulation has been investigated. Biological methods used for dye treatment are generally always effective and environmentally friendly. In this study, biosorption of the Fast Black K salt azo dye by the bacterium Rhodopseudomonas palustris 51ATA was studied spectrophotometrically, at various pH (2-10), temperatures (25 degrees C, 35 degrees C, and 45 degrees C) and dye concentrations (25-400 mg L-1). Results: The bacterial strain showed extremely good dye-removing potential at various dye concentrations. IR studies at different temperatures showed that the dye was adsorbed on the bacterial surface at lower temperatures. Characteristics of the adsorption process were investigated by Scatchard analysis at 25 degrees C and 35 degrees C. Scatchard analysis of the equilibrium binding data for the dye on this bacterium gave rise to linear plots, indicating that the Langmuir model could be applied. The regression coefficients obtained for the dye from the Freundlich and Langmuir models were significant and divergence from the Scatchard plot was observed. Conclusion: The adsorption behavior of the dye on this bacterium was expressed by the Langmuir, Freundlich, and Temkin isotherms. The adsorption data with respect to various temperatures provided an excellent fit to the Freundlich isotherm. However, when the Langmuir and Temkin isotherm models were applied to these data, a good fit was only obtained for the dye at lower temperatures, thus indicating that the biosorption ability of R. palustris 51ATA is dependent on temperature, pH, and dye concentration. (C) 2020 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B.V. All rights reserved.
Corrosion behavior of mild steel in the presence of scale inhibitor in sulfuric acid solution
(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011) Surme, Yavuz; Gurten, A. Ali; Bayol, Emel
Surfactants such as non-ionic polyethylene glycol tert-octylphenyl ether (Triton X-114) have been studied as efficient corrosion inhibitors in acid medium. In this study inhibition performance of Triton X-114 has been evaluated as corrosion inhibitor for mild steel in 0.5 mol l(-1) H(2)SO(4). The electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and linear polarization (LPR) techniques has been applied to determine the electrochemical behaviour of Triton X-114. The maximum efficiency of Triton X-114 was found as 96% at the concentration 5.0 x 10(-5) mol l(-1). The adsorption isotherm of inhibitor on the mild steel surface was found to be in a good agreement with the Langmuir and the standard free energy value (Delta G (ads) (A degrees) ) was calculated as -50.1 kJ mol(-1), which shows that adsorption of Triton X-114 on the mild steel surface improves the inhibition characteristics in 0.5 M H(2)SO(4).
Determination of Urinary Calcium and Magnesium Levels by Atomic Absorption Spectrophotometry in Hypertensive Patients
(ASIAN JOURNAL OF CHEMISTRY, 2012) Battaloglu, Rifat; Kayakirilmaz, Kadriye; Bayol, Emel
Urinary Magnesium and calcium excretion has been determined in 36 patients suffering from hypertension compared with 31 age and gender Matched normotensive control subject living in Nigde. Overnight urine samples were collected. Magnesium and calcium were determined by atomic absorption spectroscopy. The differences in urinary calcium excretion between normotensive (171.3 +/- 11.9 mg/day) and hypertensive (151.3 +/- 13.0 mg/day) and urinary magnesium excretion between normotensive (40.1 +/- 4.1 mg/day) and hypertensive (46.8 +/- 12 mg/day) were not significants (p > 0.05).
Effect of hyamine on electrochemical behaviour of brass alloy in HNO3 solution
(SPRINGER INTERNATIONAL PUBLISHING AG, 2013) Ozkir, Demet; Bayol, Emel; Gurten, A. Ali; Surme, Yavuz; Kandemirli, Fatma
The electrochemical behaviours of a brass alloy in 0.1 M nitric acid, including the hyamine inhibitor with concentrations between 2.5 x 10(-4) M and 1.0 x 10(-5) M, were studied. For this purpose, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR) techniques, and flame atomic absorption spectroscopy (FAAS) were utilised. The inhibitor molecules adsorbed on the brass surface were calculated to be in good agreement with the Langmuir adsorption isotherm and the standard free enthalpy of adsorption (Delta G (ads) (a similar to) ). Hyamine effectively improved the corrosion inhibition of brass and acted as a mixed-type inhibitor on alloy surfaces. The surface morphology of the alloy was also clarified by optical microscopic and SEM techniques. A theoretical study of the corrosion inhibition efficiency of hyamine molecule was carried out using density functional theory (DFT) at the B3LYP/6-311G(d,p) basis set level. (C) 2012 Institute of Chemistry, Slovak Academy of Sciences
Hekzametilentetraminin klorürlü ve sülfatlı ortamlarda çeliğin korozyon davranışına etkilerinin incelenmesi
(Niğde Üniversitesi, 2005) Bayol, Emel; Kayakırılmaz, Kadriye; Erbil, Mehmet
ÖZET HEKZAMETtLENTETRAMİN'tN KLORÜRLÜ VE SÜLFATLI ORTAMLARDA ÇELİĞİN KOROZYON DAVRANIŞINA ETKİLERİNİN İNCELENMESİ BAYOL, Emel Niğde Üniversitesi Fen Bilimleri Enstitüsü Kimya Anabilim Dalı Danışman : Prof. Dr. Kadriye KAYAKIRILMAZ İkinci Danışman : Prof. Dr. Mehmet ERBİL Aralık 2005, 265 sayfa Bu araştırmada, atmosferik koşullarda ve/veya azot atmosferinde, değişik sıcaklıklarda, üç elektrot tekniği ile akım-potansiyel eğrileri ve AC-impedans spektrumları oluşturularak, atmosferik koşullarda oda sıcaklığında zamana karşı; polarizasyon direnci, korozyon potansiyeli ve galvanik alam eğrileri çizilerek, hekzametüentetramin'in (HMTA'nm) çeliğin korozyonuna inhibitor etkilerini belirlemek amaçlanmıştır. Bileşimi bilinen çelik çalışma elektrodu, Pt karşı elektrot ve Ag/AgCİ referans elektrot, NaCl, Na2S04, HC1 ve H2SO4 destek elektrolit olarak kullamlmıştır. Çeliğin korozyonuna karşı, HMTA'nm inhitör etki gösterdiği, inhibitor konsantarasyonu arttıkça çelik yüzeyine inhibitor moleküllerinin adsorpsiyonundan dolayı HMTA'nm inhibitor etkisinin arttığı ve adsorpsiyonunun Langmuir adsorpsiyon izotermine uyduğu, 293 - 323 K'de 1,0x1ü"1 M HMTA içeren çözeltilerde, 283-313 K'de 200-1000 ppm HMTA içeren çözeltilerde sıcaklık arttıkça inhibisyon etkinliğininde arttığı bulunmuştur. Aktivasyon enerjisi (E*a) ve diğer teımodinamik parametreler (AG ads, AH ve AS ) hesaplanmıştır. Potansiyocünamik polarizasyon ve AC impedans ölçümlerinden elde edilen sonuçların uyumlu olduğu ve HMTA'mn klorürlü ortamda sülfatlı ortamdan daha etkin inhibitor etki gösterdiği saptanmıştır. Asidik inhibitörsüz ve inhibitörlü ortamlarda, çelik elektrodun, taramalı elektron mikroskobu ile yüzey fotoğrafları çekilerek inhibisyon etkisi değerlendirilmiştir. Deneysel veriler doğrultusunda, çeliğin korozyonunun kontrolünde, HMTA'nında kullanılabileceği sonucuna varılmıştır. Anahtar Sözcükler : Çelik, Korozyon, Hekzametilentetramin, Elektrokimyasal ölçüm, Langmuir izotermi III
İmin grubu içeren bileşiklerin demirli malzeme üzerindeki etkilerinin araştırılması
(2007) Gürten, Ali; Bayol, Emel; Gürten, Tijen
[Abstract Not Available]
Influence of polyvinylpyrrolidone on rebar corrosion in sulphate solution
(TECHNO-PRESS, 2009) Gurten, A. Ali; Bayol, Emel; Kayakirilmaz, Kadriye; Erbil, Mehmet
This paper reports the results of an experimental investigation of the polyvinylpyrrolidone (PVP) influence on the steel reinforcement corrosion and compressive strength of concretes in sulphate medium. The effect of admixture of PVP in concrete on the corrosion resistance of steel reinforced concrete was assessed by measuring electrochemical test during 60 days immersion in two different external solutions. AC impedance spectrum indicated that the resistance of PVP mixed electrodes were higher than those without PVP. The compressive strength of concrete specimens containing PVP was measured and an increase of 190%similar to 24% was observed.
Inhibition Efficiency of Benzidine for Mild Steel in Acidic Media
(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011) Ozkir, Demet; Bayol, Emel
In this study, the inhibition effect of different concentrations of benzidine possessing amine groups in its structure on the corrosion behavior of mild steel (MS) in 1.0 M HCl solution at 293 K temperature was practiced in both short and long immersion times by measuring electrochemical impedance spectroscopy (EIS), hydrogen evolution (V(H2)-t) and change of open circuit potential (E(ocp)-t). For short-term tests, potentiodynamic polarization and linear polarization resistance (R(lp)) were also studied. Polarization data indicate that this compound act as mixed-type inhibitor for mild steel in 1.0 M HCl. With regard to the results cited, it was identified that the increase in the inhibitor efficiencies with concentration was emanated from the adsorption of benzidine molecules on the electrode surface. Pertinent to this adsorption, it followed Langmuir isotherm. Adsorption equilibrium constant and adsorption free energy were determined. The effect of temperature on the corrosion behaviour in the absence of any inhibitor and in the presence of 75 mM benzidine was studied in the range of 293 323 K. Activation energies (E(a)*) were calculated from the obtained corrosion rates at different temperatures. Furthermore, in order to identify the adsorption mechanism of the inhibitor on the metal surface, the zero-charge potential (PZC) was determined by EIS measurement technique. Surface morphology of mild steel electrodes were emerged by means of the scanning electron microscope. DOI: 10.1134/S2070205111040150
Interactions of some Schiff base compounds with mild steel surface in hydrochloric acid solution
(ELSEVIER SCIENCE SA, 2008) Bayol, Emel; Gurten, Tijen; Gurten, A. Ali; Erbil, Mehmet
The inhibition effect of the Schiff bases N,N'-bis(salicylidene)-1,2-etliylenedianiine (Salen), N,N'-bis(5-methoxysalicylidene)-1,2-ethylenediamine (MeO-Salen) and N,N'-bis(5-nitrosalicylidene)-1,2ethylenediamine (NO(2)-Salen) on the corrosion of the mild steel in 1.0M HCl has been studied by electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR) and Tafel polarisation measurements. Maximum inhibition for MeO-Salen was obtained. Results showed that the inhibition efficiency have increased when the concentration of the Schiff bases have increased. Polarisation curves revealed that the Schiff bases acted as anodic inhibitors. The surface adsorption of the Schiff bases has lead to a decrease in the double layer capacitance and to an increase in polarisation resistance. The inhibitor performance depended strongly on the type of functional groups on benzene ring. The adsorption process is spontaneous one and follows Langmuir adsorption isotherm model. Scanning electron microscopy (SEM) has been applied to identify the surface morphology of the mild steel both in the absence and presence of the Schiff base molecules. (C) 2008 Elsevier B.V. All rights reserved.
Nutritional and zinc levels in serum and hair of university students in Nigde, Turkey
(ASIAN JOURNAL OF CHEMISTRY, 2007) Oztuerk, Zeynep Alan; Battaloglu, Rifat; Kayakirilmaz, Kadriye; Aksoy, Meral; Bayol, Emel
This research has been designed for the determination of the nutritional status of university students, in particular reference to dietary zinc amount taken. The aim was to find out reflection of dietary zinc to that of serum and hair zinc contents. Forty volunteers' students of Nigde University (24 females and 16 males) participated in the first step of research. Three years later, 17 females and 10 males. from this group participated for the second stage of research. Students' nutritional status was evaluated according to their food consumption and physical examination. After analyzing the collected blood and hair samples, the mineral status was also evaluated. At the two steps of research no one had any serious mineral and other nutrients deficiencies. Only one female student having mineral deficiency at the first step of work recovered after the treatment. Regression analysis showed that there was a statistically significant correlation between dietary zinc concentration and hair and serum mineral levels (r(diet-hair) = 0.500, n = 40, p < 0.01, r(diet-serum) = 0.470, n = 40, p < 0.01).
Nutritional status and calcium levels in serum and urine of primary hypertensives and normotensives
(ASIAN JOURNAL OF CHEMISTRY, 2008) Kayakirilmaz, Kadriye; Bayol, Emel; Yilmaz, Hatice Bal; Ozgun, Hacer Kutluk; Ozbek, Tulay; Topuz, Dervis; Battaloglu, Rifat
This research has been designed for the determination of the nutritional status, serum and urinary calcium (UCa) levels and correlation between UCa and blood pressure (BP). 31 Volunteers' patients with essential hypertension (HT) and 31 age- and gender-matched normotensive (NT) control subjects living in Ankara and Nigde from Turkey have participated in this study. 62 Subjects' 24 h urinary samples were collected. Besides, for determination of the correlation between 24 h UCa and overnight UCa (12 h UCa), 38 urine samples (9 patients and 29 control subjects) were collected. Nutritional status was evaluated according to their food consumption and physical examination. After analyzing the collected blood and urinary samples, the mineral status was also evaluated. Urinary and serum Ca levels were determined by flame atomic adsorption spectroscopy. The mean 24 h urinary Ca excretion rates (24 h UCaV) in hypertensive and normotensive subjects were 101 +/- 69 and 128 +/- 85 mg/day, respectively (n = 62, t = 1.378, p > 0.05). The mean serum Ca levels in HT was significantly decreased when compared with the controls (n = 26, t = 2.54, p < 0.05). In NT subjects systolic blood pressure (SBP) correlated positively with diastolic blood pressure (DBP) (r = 0.588) and UCaV (r = 0.516) and negatively with dietary Ca (r = -0.617, for all p < 0.05). In NT group DBP correlated positively with body mass index (BMI) (p < 0.05). In HT subjects, SBP correlated positively with DBP (r = 0.741) and negatively with serum Ca (r = -0.633), DBP also correlated negatively with serum Ca (r = 0.727). Among the 38 subjects, overnight calcium excretion rate (12 h UCaV) was correlated with the 24 h UCaV (y = 0.8279x + 42.735, r = 0.81, R-2 0.653, p < 0.05).
Nutritional Status and Magnesium Levels in Serum and Urine of Primary Hypertensives and Normotensives
(ASIAN JOURNAL OF CHEMISTRY, 2011) Kayakirilmaz, Kadriye; Bayol, Emel; Yilmaz, Hatice Bal; Ariogul, Servet
This research has been designed for the determination of the nutritional status, serum and urinary magnesium (UMg) levels and I correlation between urinary magnesium and blood pressure (BP). Thirty two volunteers' patients with essential hypertension (HT) and 35 normotensive (NT) control subjects, aged 21-79 years, have participated in this study. Fifty five subjects 24-h urinary samples were collected (28NT and 27HT). Besides, for determination of the correlation between 24 hUMgV and overnight excretion rate urinary magnesium (12 hUMgV), 43 urine samples were collected. Nutritional status was evaluated according to their food consumption and physical examination. After analyzing the collected blood and urinary samples, the mineral status was also evaluated. Among 13 hypertensive subjects three women had serum magnesium values lower than 1.7 mg Mg/dL (1.38-1.68 %). After 6 months treatment with magnesium, serum magnesium concentrations have increased to normal levels. In both groups blood pressure was positively correlated with UMgV and in hypertension group blood pressure was negatively correlated with serum magnesium levels (p < 0.05). Among the 43 subjects, 12 h UMgV was correlated with the 24 h UMgV and also in normotensive group UMgV was correlated positively with UCaV (p < 0.05). Overnight urinary magnesium excretion rate was correlated with the 24 h UMgV, so 12 h UMgV should be usually employable.
Systematic corrosion investigation of various Cu-Sn alloys electrodeposited on mild steel in acidic solution: Dependence of alloy composition
(ELSEVIER SCIENCE SA, 2009) Surme, Yavuz; Gurten, A. Ali; Bayol, Emel; Ersoy, Ersay
Copper-tin alloy films were galvanostatically electrodeposited on the mild steel (MS) by combining the different amount of Cu and Sri electrolytes at a constant temperature (55 degrees C) and pH (3.5). Alloy films were characterized by using the energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and micrographing techniques. Corrosion behaviours were evaluated with electrochemical impedance spectrometry (EIS) and electrochemical polarization measurements Time gradient of electrolysis process was adjusted to obtain same thickness of investigated alloys on MS. The systematic corrosion investigation of various Cu(x)-Sn(100-x) (x = 0-100) alloy depositions on MS substrate were carried out in 0.1 M sulphuric acid medium. Results indicate that the corrosion resistance of the alloy coatings depended on the alloy composition, and the corrosion resistance increased at Cu-Sn alloy deposits in proportion to Sri ratio. (C) 2009 Elsevier B.V All rights reserved.
The effect of temperature and concentration on the inhibition of acid corrosion of carbon steel by newly synthesized Schiff base
(ELSEVIER SCIENCE INC, 2015) Gurten, A. Ali; Keles, Hulya; Bayol, Emel; Kandemirli, Fatma
Inhibition effect of Schiff base namely 1-(2-hydroxybenzylidene)-3-(2,5-dioxoimidazolidin-4-yl) urea (ALS) was studied on carbon steel corrosion in 1.0 M HCl by using the electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and linear polarization (LPR) and quantum chemical study. The values of activation energy (E-a), equilibrium constant (K-ads), adsorption free energy Delta G(ads)(o), adsorption enthalpy Delta H-ads(o) and adsorption entropy Delta S-ads(o) were discussed. The adsorption of inhibitor on metal followed Langmuir's adsorption isotherm. The thermodynamic parameters of adsorption reveal that there is a strong interaction between inhibitor and carbon steel. The highest inhibition efficiency was observed 5.0 x 10(-4) M ALS concentration at 318 K. SEM and EDX observations confirmed the existence of protective inhibitor film on metal surface. Quantum chemical study supports the comparative inhibition effect of ALS. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
The inhibition effect of Azure A on mild steel in 1 M HCl. A complete study: Adsorption, temperature, duration and quantum chemical aspects
(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Ozkir, Demet; Kayakirilmaz, Kadriye; Bayol, Emel; Gurten, A. Ali; Kandemirli, Fatma
In this study, inhibition effect of Azure A on mild steel in 1.0 M HCl were evaluated by using electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization and scanning electron microscope (SEM) methods. These studies were carried out at different concentrations, temperatures and durations. The inhibitor molecules were chemisorbed on electrode surface according to the Langmuir adsorption isotherm. The quantum chemical calculations were employed to give further insight into the inhibition mechanism of Azure A. (C) 2011 Elsevier Ltd. All rights reserved.
THERMODYNAMIC STUDY AND ELECTROCHEMICAL INVESTIGATION OF CALCEIN AS CORROSION INHIBITOR FOR MILD STEEL IN HYDROCHLORIC ACID SOLUTION
(SOC CHILENA QUIMICA, 2013) Ozkir, Demet; Bayol, Emel; Gurten, A. Ali; Surme, Yavuz
The corrosion behaviour of mild steel in 1.0 M HCl solution containing different concentrations of Calcein at different temperatures was investigated using the impedance, potentiodynamic polarization and linear polarization techniques. Long term tests were accomplished by hydrogen gas evolution and impedance measurements. The results showed that inhibition efficiency has increased with the inhibitor concentration and temperature increment. The adsorption of the inhibitor on the mild steel surface obeyed the Langmuir isotherm. Activation energy values at concentrations of Calcein were lower than that of uninhibited system. The thermodynamic parameters of adsorption deduced reveal a strong interaction of Calcein on the mild steel surface.
Thermodynamic study and electrochemical Investigation of calcein as corrosion Inhibitor for mild steel in hydrochloric acid Solution
(Sociedad Chilena de Quimica, 2013) Ozkir, Demet; Bayol, Emel; Ali Gürten, A.; Sürme, Yavuz
The corrosion behaviour of mild steel in 1.0 M HCl solution containing different concentrations of Calcein at different temperatures was investigated using the impedance, potentiodynamic polarization and linear polarization techniques. Long term tests were accomplished by hydrogen gas evolution and impedance measurements. The results showed that inhibition efficiency has increased with the inhibitor concentration and temperature increment. The adsorption of the inhibitor on the mild steel surface obeyed the Langmuir isotherm. Activation energy values at concentrations of Calcein were lower than that of uninhibited system. The thermodynamic parameters of adsorption deduced reveal a strong interaction of Calcein on the mild steel surface.

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