Browsing by Author "Zorer, Ozlem Selcuk"

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Accumulation and Tolerance of Pb in Some Bioenergy Crops
(Hard, 2018) Celebi, Seyda Zorer; Ekin, Zehra; Zorer, Ozlem Selcuk
Contamination of agricultural soil is a worldwide problem, with heavy metals being a major part of the concern. Bioenergy crop production is also a profitable phytoremediation strategy using biofuel crops for both utilization and remediation of contaminated soil. To investigate lead (Pb) accumulation and tolerance of three different energy crop cultivars, three-week-old healthy seedlings were grown in Hoagland solution supplemented with five different concentrations of Pb 0, 25, 50, 100, and 150 mg/kg. At the end of 30 days, Pb content and translocation, tolerance index, bioconcentration factor, and growth parameters of the plants were evaluated in the study. Results showed that increasing Pb concentrations did not affected the growth and development of Sunburst (Panicum virgatum L.) and Dincer (Carthamus tinctorius L.) cultivars. The highest Pb contents were also found in roots and shoots of Sunburst and Tarsan-1018 (Helianthus annuus L.) cultivars. Dincer cultivar has a high ability to transfer Pb from root to shoot when compared to others. These results suggest that these cultivars may be good candidates for remediation of Pb-contaminated areas for use in biofuel production.
Adsorption Behaviours of Th(Iv) and U(Vi) Using Nitric Acid (Hno3) Modified Activated Carbon: Equilibrium, Thermodynamic and Kinetic Studies
(Taylor & Francis Ltd, 2021) Oter, Cigdem; Zorer, Ozlem Selcuk
In order to research the sorption of thorium(IV) and uranium(VI) ions from aqueous solutions, the granular-activated carbon was modified with nitric acid. The modified adsorbent was identified by BET, elemental analysis, SEM and FTIR method. The influences of different parameters such as pH, contact time, temperature and initial concentration were investigated using batch system. Adsorption of Th(IV) and U(VI) onto modified carbon has been evaluated in terms of equilibrium, kinetics and thermodynamics studies. When the obtained results of thorium(IV) and uranium(VI) sorption onto modified adsorbent was applied to kinetic models, it was observed that the experimental results much better fitted the pseudo-second-order kinetic model. Adsorption process was better explained by Langmuir isotherm in comparison with other isotherms. Thermodynamic data were calculated from the sorption isotherms. Results suggested that the adsorption of Th(IV) and U(VI) on modified adsorbent was an endothermic and spontaneous process.
Adsorption of Uranium (Vi) From Aqueous Solutions Using Boron Nitride/Polyindole Composite Adsorbent
(Wiley, 2024) Emre, Deniz; Zorer, Ozlem Selcuk; Bilici, Ali; Budak, Erhan; Yilmaz, Selehattin; Kilic, Necla Caliskan; Sogut, Eda Gokirmak
Turbostratic boron nitride (tBN) surface is modified with polyindole (PIn) by a facile polymerization technique and the uranyl adsorption efficiency of this mesoporous hybrid is investigated. The successful surface modification is confirmed by FT-IR, Raman, XRD, TEM, SEM, EDX, EDS mapping XPS, BET, and zeta potential techniques. The batch experiments are performed in various temperatures (T), contact times (t), pH, and initial solution concentrations (C-0) to evaluate its adsorption performance. The optimum adsorption performance is achieved at pH = 5.0-5.5, T = 307 K, t = 10 min, C-0 = 18 mg L-1. These experimental results are evaluated using Freundlich, Redlich-Peterson, and Langmuir isotherm models, which presents equivalent regression coefficients. Maximum adsorption capacity (q(m)) of the nanoadsorbent (tBN/PIn), determined by the Langmuir isotherm, is 315.29 mg g(-1). The adsorption kinetics of uranyl ions on tBN/PIn are in harmony with the pseudo-second order model. tBN/PIn nanoadsorbent provides high adsorption efficiency even at exceptionally low UO22+ concentration range (4-40 mg L-1) and low adsorbent mass (0.005 g). XPS analysis results show that 0.05% of uranium is adsorbed on tBN/PIn via mainly U-O coordination. The results of present study demonstrate that tBN/PIn can a potential adsorbent for removing uranium from aqueous solutions.
Chemometric Data Analysis of Gross Radioactivity and Heavy Metal Concentrations in Soil and Sediments of Bendimahi River, Turkey
(Springer, 2020) Sehribanoglu, Sanem; Zorer, Halil; Zorer, Ozlem Selcuk
This study deals with radioactivity and heavy metal distribution and statistical analyses in the Bendimahi River Basin, which is within the Lake Van Closed Basin, Turkey. In order to identify the relationships between measured variables and to categorize soils and sediments collected at 15 sites on Bendimahi River, factor and cluster analysis have been applied. The data set is constituted of 9 radiological and physico-chemical variables, including gross alpha and gross beta activities and Pb, Zn, Cu, Cr, Cd, Co and Mn concentrations. Factor and cluster analysis were used to describe the relationship and similarity among data sets (variables) for the Bendimahi River. The convergence diagnostics such as trace plot and kernel density were applied to determine the convergence criteria to the data sets.
Comprehensive Natural Radioactivity and Pollution Risk Assessments of Aquatic Media and Sediment in Lake Van (T?rkiye)
(Pergamon-elsevier Science Ltd, 2023) Zorer, Ozlem Selcuk; Yorgun, Nergiz Yildiz; Ozdemir, Omer Faruk; Ogun, Erdal; Aydin, Harun; Atici, Ataman Altug; Elp, Mahmut
This paper studies the radionuclide (137Cs, 226Ra, 232Th, 40K) activity concentrations and gross radioactivities in waters and sediments of Lake Van, which is the third largest closed lake (with no natural or artificial outlet) within the Earth. The physico-chemical parameters were measured and evaluated in the lake waters. The mean gross alpha activities in surface, middle and bottom waters are 0.04, 0.03 and 0.03 Bq/L, respectively, and in the same order, the mean gross beta activities are 0.30, 0.23 and 0.33 Bq/L, respectively. In sediment samples, the mean activity concentrations were measured as 1.98 Bq/g for gross-alpha, 3.46 Bq/g for gross-beta, 48.3 Bq/kg for 226Ra, 32.0 Bq/kg for 232Th, 540.1 Bq/kg for 40K and 25.9 Bq/kg for 137Cs. The radiation hazard parameters values based on the measured activities were calculated and Raeq values are lower than the world average value in all samples, while Dout and AED values are relatively high in some sediment samples.
The Concentration of 238u and the Levels of Gross Radioactivity in Surface Waters of the Van Lake (Turkey)
(Springer, 2011) Zorer, Ozlem Selcuk; Sahan, Tekin
Gross alpha and gross beta activities and U-238 concentrations were determined in 18 surface water samples collected from Van Lake. The instrumentations used to count the gross alpha and gross beta activities and to determine the U-238 concentrations were alpha/beta counter of the multi-detector low background system (PIC-MPC-9604) and Inductively Coupled Plasma-Mass Spectrometry (Thermo Scientific Element 2), respectively. Concentrations ranging from 0.001 to 0.021 Bq L-1 and from 0.111 to 2.794 Bq L-1 were observed for the gross alpha and beta activities in surface waters, respectively. For all samples the gross beta activities were higher than the corresponding gross alpha activities. The results indicated that the gross alpha radioactive contamination in water samples was lower than recommended values for the guideline of drinking waters and most of the gross beta activities in water samples were higher than those in the same procedure. The U-238 concentrations ranged from 74.49 to 113.2 mu g L-1 in surface waters. The obtained results have showed that U-238 concentrations are higher than guideline values for uranium.
Electrochemical Determination of Pterostilbene at a Cathodically Pretreated Boron-Doped Diamond Electrode Using Square-Wave Adsorptive Anodic Stripping Voltammetry in Cationic Surfactant Media
(Elsevier Science Sa, 2016) Yigit, Aydin; Yardim, Yavuz; Zorer, Ozlem Selcuk; Senturk, Zuhre
In the present paper, an electrochemical method was developed for the determination of pterostilbene (a phenolic phytoalexin) using adsorptive anodic stripping voltammetry at a cathodically pretreated boron doped diamond electrode. The oxidation of compound was irreversible and exhibited an adsorption controlled process which is of pH dependence. The sensitivity of the stripping voltammetric measurements was significantly improved in the presence of cationic surfactant, cetyltrimethylammonium bromide (CTAB). Using square-wave stripping mode, a highly linear analytical curve was obtained for pterostilbene determination in 0.1 M HNO3 solution containing 2 x 10(-4)M CTAB at +0.78V (vs. Ag/AgCl) (after 30 s accumulation at open-circuit condition). The process could be used in the range of 0.005-1.0 mu g mL(-1) (2.0 x 10(-8)-3.9 x 10(-6)M), with a detection limit of 0.0011 mu gmL(-1) (4.3 x 10(-9) M). The proposed method was successfully applied to measure the concentration of pterostilbene in the commercial dietary supplements, with results similar to those obtained using a HPLC method at 95% confidence level. As far as it could be verified, the proposed method is the first one based on the electrochemical investigation of pterostilbene. (C) 2016 Elsevier B.V. All rights reserved.
Evaluations of Environmental Hazard Parameters of Natural and Some Artificial Radionuclides in River Water and Sediments
(Elsevier Science Bv, 2019) Zorer, Ozlem Selcuk
In order to evaluate the radiological baseline in the Lake Van basin, U-238, Th-232,, Ra-226 Cs-137 and K-40 activity concentrations and gross radioactivity were determined in twelve river water and sediment samples. To determine radionuclide activities and gross radioactivity, a gamma ray spectrometer with HPGe detector and a gross-alpha/beta-counting system low background multi-detector were used, respectively. Therefore, based on the measured activity concentrations,. parameters of radiological hazards such as radium equivalent activity, outdoor absorbed dose rate, annual effective dose, and internal and external hazard indices were calculated. R-eq, H-ex and H-in and values in samples were generally lower than worldwide average values; while D-out, and AED values were higher than worldwide average values in general.
Kinetic, Isothermal and Thermodynamic Studies on Th(Iv) Adsorption by Different Modified Activated Carbons
(Springer, 2020) Oter, Cigdem; Zorer, Ozlem Selcuk
In this study, the performance of modified adsorbents obtained from activated carbon for the adsorption of thorium(IV) ions from aqueous media was investigated. The analytical and spectroscopic methods such as FT-IR, BET, SEM and UV-Vis were used to examine the properties of the modified materials. According to the analysis results, the both adsorbents had large surface areas after modification. Then, temperature, pH, mixing time and solution concentration parameters were observed to determine optimum thorium adsorption conditions on modified materials. The obtained results from the experiments were applied different three kinetic models and adsorption isotherms and thermodynamic parameters were calculated and then all of the results were interpreted. The adsorption process for both adsorption systems was observed to be compatible with the pseudo-second-order kinetic model. The adsorption equilibrium data were best described by the Langmuir model for modified adsorbent with KMnO4 and by the Freundlich model for modified adsorbent with NaOH. Furthermore, the calculated thermodynamic parameters (Delta G degrees, Delta H degrees and Delta S degrees) showed that the both adsorption processes were endothermic and spontaneous. The data show that modified adsorbents can be used as influential and low-cost adsorbents to remove thorium ion. Modified new adsorbents were highly selective for thorium ion in competitive adsorption studies.
Measurement of Gross Alpha and Gross Beta Activity Concentrations in Human Tooth
(Elsevier Sci Ltd, 2010) Sogut, Omer; Aydin, Mehmet Fatih; Kucukonder, Erdal; Zorer, Ozlem Selcuk; Dogru, Mahmut
The gross alpha and gross beta activity concentrations were measured in human tooth taken from 3 to 6 age-groups to 40 and over ones. Accumulated teeth samples are investigated in two groups as under and above 18 years. The gross alpha and beta radioactivity of human tooth samples was measured by using a gas-flow proportional counter (PIC-MPC 9604-alpha/beta counter). In tooth samples, for female age-groups, the obtained results show that the mean gross alpha and gross beta activity concentrations varied between 0.534-0.203 and 0.010-0.453 Bq g(-1), and the same concentrations for male age-groups varied between 0.009-1.168 and 0.071-0.204 Bq g(-1), respectively. (C) 2009 Elsevier Ltd. All rights reserved.
Pollution and Health Risk Evaluations From Gross Radioactivity in Drinking Waters in Reyhanli District, Hatay
(Springer int Publ Ag, 2022) Sogut, Omer; Alnashar, Muhammed Salih; Eyicil, Mustafa; Zorer, Ozlem Selcuk
The natural gross radioactivity concentrations in drinking water collected from the Reyhanli District, Hatay, were measured. The gross alpha/beta radioactivity levels were measured in August 2021. A proportional counter was used to determine gross alpha/beta radioactivity levels in drinking waters. The activity levels of gross alpha/beta in drinking waters ranged from 0.001 +/- 0.000 to 0.020 +/- 0.002 Bq/L and 0.015 +/- 0.003 to 0.715 +/- 0.126 Bq/L, respectively, according to results obtained from the activity measurements. The results of the gross beta radioactivities were found reasonably high compared to the results of the gross alpha activity levels. The measured gross alpha/beta activity concentrations are smaller than the 0.5-Bq/L and 1-Bq/L limit values recommended by WHO and EPA. The annual effective dose and excess lifetime cancer risk parameters were calculated using gross alpha/beta radioactivity concentrations.
Radiochemical Analysis of Milk Samples and Dose Exposures for Adults, Children, and Infants
(Asce-amer Soc Civil Engineers, 2018) Sogut, Omer; Boynukalin, Baris; Zorer, Ozlem Selcuk
The natural gross radioactivity in milk from farms in different locations in Van and in milk purchased from Kahramanmara markets were determined. In the milk samples, natural gross alpha and beta activity concentrations were measured. The evaporation and ashing procedures were applied to the milk samples collected from farms and markets. Nuclear spectroscopic systems containing gas-flow proportional counters were used to measure the gross alpha and beta activity concentrations of the milk samples. The gross radioactivity in milk from markets was generally lower than the gross radioactivity in milk from farms. The annual effective dose resulting from gross radioactivity for adults, children, and infants and excess lifetime cancer risk values were calculated. The highest total annual effective dose (AED) values were 1,105.9mSvy-1 for adults, 6,456.2mSvy-1 for children, and 10,267.0mSvy-1 for infants in milk samples. The excess lifetime cancer risk (ELCR) values from gross alpha and beta activities range from 0.010 to 3.870 in milk samples.
Radiological Hazard Assessment of Natural Gross Radioactivity in Some Cosmetic Products
(Taylor & Francis Ltd, 2018) Sogut, Omer; Zorer, Ozlem Selcuk; Reyhanlioglu, Hilal
Many kinds of cosmetic products were analyzed to determine gross radioactivity. In this study, gross alpha/beta radioactivity concentrations in 51 cosmetic samples were determined. The examined cosmetic products consist of blusher, eye shadow, lipstick, nail polish, shampoo, hand cream, cellulite cream, baby powder, soap, and toothpaste. The gross alpha-beta activity concentrations were measured with a nuclear spectroscopic system which contains gas-flow proportional counters. The highest gross alpha/beta activity concentrations were found in eye shadow samples of 1.621Bq g(-1) for alpha and 6.471Bq g(-1) for beta. The total effective doses due to gross radioactivity for skin were calculated. Although the effective dose of eye shadow samples had the highest value, the effective doses due to gross radioactivity concentrations in this study were found to be lower than the radiological limits given by the authorities.
Synthesis and Characterization of 2-hydroxyethylmethacrylate/2-(3-indol-yl)ethylmethacrylamide-based Novel Hydrogels as Drug Carrier With in Vitro Antibacterial Properties
(Wiley, 2017) Ilgin, Pinar; Zorer, Ozlem Selcuk; Ozay, Ozgur; Boran, Gokhan
In this study, a new cationic monomer 2-(3-indol-yl)ethylmethacrylamide (IEMA) derived from tryptamine was synthesized in a single step and characterized by Fourier transform infrared (FTIR), H-1-NMR, and C-13-NMR. Then, one-step preparation of novel poly[2-hydroxyethylmethacrylate-c-2-(3-indol-yl)ethylmethacrylamide], or p(HEMA-c-IEMA), copolymeric hydrogels has been performed successfully with IEMA and 2-hydroxyethylmethacrylate (HEMA) as monomers using free radical aqueous polymerization. The hydrogels were characterized with scanning electron microscopy, FTIR, elemental analysis, thermogravimetric analysis, and texture profile analysis instruments. p(HEMA-c-IEMA) hydrogels were used for swelling, diffusion, drug release, and antibacterial activity studies. The drug-release behavior of the hydrogels was determined as a function of time at 37 degrees C in pH1.2 and 7.2. The swelling and drug-release studies showed that an increased IEMA amount caused a higher increase in swelling and drug-release values. Additionally, zero-order, first-order, and Higuchi equation kinetic models were applied to the drug-release data, and the data fit well in the Higuchi model, and the Peppas power-law model was applied to the release mechanism. Finally, the antibacterial activities of the hydrogels were screened against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45550.
Synthesis and Characterization of a Molecularly Imprinted Polymer Adsorbent for Selective Solid-Phase Extraction From Wastewater of Propineb
(Springer, 2022) Oter, Cigdem; Zorer, Ozlem Selcuk
Pesticide residues, which have become a critical problem today, negatively affect the living life and cause concern for the future life. Different methods are being developed to eliminate the problems caused by pesticides and pesticide residue analysis. In this study, a new molecularly imprinted polymer (MIP) has been synthesized for using methacrylic acid as the functional monomer and propineb, a fungicide, as the template molecule. The selectivity and binding properties of MIP were compared with non-imprinted polymer (NIP). MIP particles were used as an adsorbent in the solid-phase extraction column, and various extraction parameters were extensively optimized to evaluate the extraction performance. It was determined that under optimum extraction conditions, MIP showed higher selectivity and extraction capacity toward propineb compared to commercial C-18 column and NIP. As a result, the developed solid phase extraction method was optimized for propineb residue analysis, and high extraction efficiency was obtained. This method, which is low cost, requires very little use of organic solvents, is fast and easy, is selective and environmentally friendly, is very useful for the purification of wastewater from pollutants.
Synthesis and Characterization of Utsa-76 Metal Organic Framework Containing Lewis Basic Sites for the Liquid-Phase Adsorption of Uvi
(Elsevier, 2021) Ozturk, Mehmet; Zorer, Ozlem Selcuk; Gulcan, Mehmet
UTSA-76 encoded MOF structure containing Lewis basic groups was efficiently synthesized and characterized for the removal of U-VI from the liquid phase by using adsorption technique. H-1, C-13-NMR, FT-IR, P-XRD, TEM, TEMEDX, BET, SEM and SEM-EDX mapping techniques were applied to define this adsorbent material. Adsorption of U-VI on the synthesized UTSA-76 structure was investigated depending on the parameters of pH, temperature, mixing time and solution concentrations. In the kinetic of adsorption process, not only the pseudo-second-order kinetic, but also film diffusion was effective. The adsorption equilibrium of U-VI on UTSA-76 explained better by Langmuir isotherm model and the qmax from Langmuir isotherm was calculated as 91.31 mg/g. The synthesized MOF structure (UTSA-76) demonstrated a removal rate from 12 ppm to 0.25 ppm in 45 min to a very low UO22+ ion concentration of about 98 % using a low adsorbent mass of 5 mg, and UTSA-76 with this adsorption performance will be among the highly preferred effective adsorbents for uranium adsorption.
Utilization of a Novel Polymer-Clay Material for High Elimination of Hazardous Radioactive Contamination Uranium(Vi) From Aqueous Environments
(Elsevier, 2021) Yilmaz, Sakir; Zengin, Adem; Sahan, Tekin; Zorer, Ozlem Selcuk
In the current work, the effect of the poly(2-aminoethyl methacrylate)-grafted kaolin (PAEMA@KLN) was investigated for the potential removal of U(VI) from aqueous samples. This novel adsorbent prepared for U(VI) removal was characterized by various techniques (Fourier transform infrared spectrometry (FTIR), energy-dispersive x-ray analysis (EDX), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS)). Response surface methodology (RSM) was utilized to optimize and model the removal of U(VI) by PAEMA@KLN from aqueous environments. The effects of different parameters such as pH, U(VI) concentration (Co), PAEMA@KLN dosage, and shaking time were optimized by central composite design (CCD) combined with RSM. The optimum points were numerically determined as 5.07 for pH, 35.16 mg/L for Co, 13.73 mg for PAEMA@KLN dosage, and 92.09 min for the shaking time. The maximum removal was obtained at 96.03% under the optimum conditions. The kinetic data was better described by the pseudo-second-order and Weber-Morris models. U(VI) removal onto PAEMA@KLN follows the Langmuir isotherm model. Thermodynamic studies showed that U(VI) removal by PAEMA@KLN was spontaneous and exothermic in nature. The results indicate that PAEMA@KLN is a promising adsorbent for the effective removal of radionuclides like U(VI) from aqueous media. (C) 2021 Elsevier B.V. All rights reserved.