Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Duran, Celal(5)
- Yücel, Cem(4)
- Arslan, Mehmet(3)
- Ozdes, Duygu(3)
- Gundogdu, Ali(2)
- Imamoglu, Mustafa(2)
- Kaygusuz, Abdullah(2)
- Senturk, Hasan Basri(2)
- Serencam, Huseyin(2)
- Sipahi, Ferkan(2)
- Temizel, İrfan(2)
- Topal, Fevzi(2)
- Abdioğlu Yazar, Emel(1)
- Abdioğlu, Emel(1)
- Acar, Ramazan(1)
- Adiguzel, Ahmet(1)
- Adiguzel, Gulsah(1)
- Akcay, Hakki Turker(1)
- Akpınar, İ.(1)
- Akpınar, İbrahim(1)
- Akyürek, suat(1)
- Albayrak, Sinem(1)
- Altay, Ahmet(1)
- Arslan, Sumeyya(1)
- Ashyralyyev, Charyyar(1)
- Aslan, Zafer(1)
- Avan, Hilal(1)
- Aydın, Şeyma(1)
- Baltaci, Mustafa Ozkan(1)
- Baltacı, Cemalettin(1)
- Bicer, Burcin(1)
- Bingöl, Şinasi(1)
- Burnaz, Nesibe Arslan(1)
- Büyükgüngör, Orhan(1)
- Demircioʇlu, Zeynep(1)
- Deveci, M.(1)
- Doğangün, Adem(1)
- Durmaz, Lokman(1)
- Eker, Çiğdem Saydam(1)
- Genc, Berna(1)
Yayınlar
- MakaleYalnız künye2020Eocene tonalite–granodiorite from the Havza (Samsun) area, northern Turkey: adakite-like melts of lithospheric mantle and crust generated in a post-collisional setting
Temizel, Irfan; Arslan, Mehmet; Yücel, Cem; Abdioğlu Yazar, Emel; Kaygusuz, Abdullah; Aslan, Zafer
Eocene intermediate to felsic plutons of different sizes and compositions are widespread in the Eastern Pontides Orogenic Belt in northern Turkey. Of these, the Taşlık Tepe pluton in the Havza (Samsun) area is fine-to-medium-grained, with granular, porphyritic, and micrographic textures, and include mafic microgranular enclaves (MMEs). LA-ICP-MS U-Pb zircon dating yielded emplacement ages of 42.9 (± 1.4) and 40.5 (± 1.3) Ma for the host granodioritic pluton and the dioritic MMEs, respectively. Petrochemically, the host pluton has I-type, high-K calc-alkaline, and metaluminous-to-slightly peraluminous features (A/CNK = 0.95–1.06). The host pluton also shows geochemical features of adakite-like rocks with high SiO2 (67–68 wt%) and Al2O3 (15.5–16.0 wt%) content and Ba/La (17–23), Sr/Y (40.7–61.6), and LaN/YbN (14.4–23.7) ratios and low Y (8.2–9.9 ppm) and YbN (3.1–4.4) contents. Whole-rock major and trace element variations suggest that fractional crystallisation played a significant role in the pluton evolution. The N-MORB normalised trace element patterns of the pluton are similar to those of MMEs with enrichment in large-ion lithophile elements, Th and Ce, and negative Nb and Ti anomalies. Chondrite-normalised rare earth element plots show moderate-to-highly enriched concave patterns (LaN/LuN = 14.2–21.6) with insignificant negative Eu anomalies (EuN/Eu* = 0.86–1.14), all of which imply hornblende fractionation during magmatic evolution. The pluton samples have 87Sr/86Sr ratios of 0.704767 to 0.704927, 143Nd/144Nd ratios of 0.512767–0.512774, εNd values of (+2.52)–(+2.65), and δ18O values of 7.9–9.7‰. The isotopic compositions of the host pluton and MMEs are similar to I-type granitoids derived from mantle sources. The MMEs show incomplete magma mixing/mingling, representing small bodies of mafic parental magma. Combined with regional studies, these new data suggest that the parental magma of the studied adakite-like pluton was generated from the lithospheric mantle and then modified by fractional crystallisation and assimilation in a post-collisional setting.
- MakaleYalnız künye2020Eocene I-type magmatism in the Eastern Pontides, NE Turkey: insights into magma genesis and magma-tectonic evolution from whole-rock geochemistry, geochronology and isotope systematics
Kaygusuz, Abdullah; Yücel, Cem; Arslan, Mehmet; Temizel, İrfan; Yi, Keewook; Jeong, Youn-Joong; Siebel, Wolfgang; Sipahi, Ferkan
The Eastern Pontides orogenic belt in NE Turkey hosts numerous I-type plutons of Eocene epoch. Here, we report new U–Pb SHRIMP zircon ages and in situ zircon Lu-Hf isotopes along with bulk-rock geochemical and Sr-Nd-Pb-O isotope data from the Kemerlikdağı, Aydıntepe and Pelitli plutons and mafic microgranular enclaves (MMEs) to constrain their parental melt source(s) and evolutionary processes. U-Pb SHRIMP zircon dating yielded crystallization ages between 45 and 44 Ma for the studied plutons and their MMEs. The plutons range from gabbro to granite and have I-type, medium to high-K calc-alkaline, and metaluminous to slightly peraluminous characteristics. On the primitive mantle-normalized multi-trace-element variations, the plutons and their MMEs are characterized by significant enrichment in LILE/HFSE. Chondrite-normalized REE patterns of the plutons and their MMEs are close to each other and show moderate enrichment with variable negative Eu anomalies. The studied plutons have fairly homogeneous isotope composition (87Sr/86Sr(i) = 0.70502 to 0.70560; εNd(i) = +0.9 to–1.4; δ18O = +5.0 to +8.7‰, εHf(i) =–2.2 to +13.5). The MMEs show medium to high-K calc-alkaline and metaluminous character. Although the isotope signatures of the MMEs (87Sr/86Sr(i) = 0.70508 to 0.70542; εNd(i) = +0.9 to −1.1; δ18O = +5.8 to +8.0, εHf(i) = +4.3 to +10.4) are very similar to those of the host rocks. Fractionation of plagioclase, amphibole, pyroxene and Fe-Ti oxides played an important role in the evolution of the plutons. The isotopic composition of the studied plutons and MMEs are similar to I-type plutons derived from mantle sources. The MMEs show incomplete magma mixing/mingling, representing small bodies of mafic parental magma. The parental magma(s) of the studied plutons were generated from the enriched lithospheric mantle and then modified by fractional crystallisation, and lesser assimilation and mixing/mingling in the crustal magma chambers.
- MakaleYalnız künye2019Geochronology, geochemistry, and petrology of adakitic Pliocene–Quaternary volcanism in the Şebinkarahisar (Giresun) area, NE Turkey
Yücel, Cem
The Pliocene–Quaternary volcanics in NE Turkey are mainly hornblende–phyric trachyandesites having a narrow range of SiO 2 from 61.88 to 63.00 wt.% and exhibiting adakitic signatures with their Na 2 O (3.67–4.27 wt.%), Al 2 O 3 (16.19–16.80 wt.%), Y (14.1–16.5 ppm) contents and K 2 O/Na 2 O (0.87–1.12), Sr/Y (44.24–54.90), and La/Yb (36.80–43.88) ratios. Plagioclases as the main mineral phases show a wide range of compositions, and weak normal and reverse zoning. Hornblendes are generally edenite and pargasite (Mg#: 0.39–0.74). Clinopyroxenes are augite (Mg#: 0.58–0.76). Biotites have Mg# ranging from 0.45 to 0.66. The textural and compositional variations indicate disequilibrium crystallization possibly arising from magma mixing. The U–Pb zircon dating of the adakitic volcanics yielded 3.4–1.9 Ma. The studied rocks display moderate light rare earth element /heavy rare earth element ratios and enrichment in the lithophile element and depletion in high field strength element, implying that the parental magmas were derived from mantle sources previously enriched by slab-derived fluids and/or subducted sediments. The crystallization temperature and pressure estimations based on the clinopyroxene thermobarometry range from 1144 to 1186°C and from 3.92 to 7.97 kbar, respectively. Hornblende thermobarometry, oxygen fugacity, and hygrometer calculations yielded results as 908–993°C at a pressure of 2.87–5.22 kbar, water content of 4.4–8.4 wt.%, and relative oxygen fugacity (ΔNNO log units) of −0.6 to 0.9, respectively. Biotite thermobarometry suggests relatively higher oxygen fugacity conditions (10 –13.33 to 10 –17.60 ) at temperatures of 676–819°C and at pressures from 1.15 to 1.76 kbar. In the light of the obtained data and modelling, it can be concluded that the magmas of the adakitic volcanics were derived from enriched mantle source through relatively higher partial melting and experienced magma mixing with melts at the crustal level. Additionally, the fractional crystallization and assimilation-fractional crystallization processes may have played an important role during the evolution of the studied volcanics.
- MakaleAçık Erişim2019Anticholinergic and antidiabetic effects of isoeugenol from clove (Eugenia caryophylata) oil
Topal, Fevzi
Isoeugenol (2-methoxy-4-(prop-1-en-1-yl)phenol), a component of from clove (Eugenia caryophylata) oil, is a starting material for both the biotechnological and synthetic production of vanillin and vanillic acid. In this article, the isoeugenol showed excellent inhibitory effects against some metabolic enzymes such as acetylcholinesterase (AChE) enzymes, α-glycosidase, and α-amylase. Isoeugenol has the IC50 values of 411.5 for α-amylase, 19.25 nM for α-glycosidase and 77.00 nM for AChE. Ki values of isoeugenol were found as 21 ± 9 nM and 16 ± 3 nM against α-glycosidase and AChE, respectively. On the other hand, tacrine as standard AChE inhibitor exhibited IC50 value of 20.38 nM. α-Glycosidase inhibitors, commonly referred to as starch blockers, are anti-diabetic drugs that help reduce edible blood glucose levels. AChE inhibitors are used for the treatment of some neurologic degenerational diseases, which involve Alzheimer’s disease. Also, there is a growing interest and the need to search for newer effective and safe AChE, α-amylase, and α-glycosidase inhibitors for the treatment of some metabolic disorder.
- MakaleAçık Erişim2019The inhibition profile of sesamol against α-glycosidase and acetylcholinesterase enzymes
Topal, Meryem
Sesamol (1,3-benzodioxol-5-ol) is found in the oilseed product, sesame. In our study, the inhibitory effects of sesamol compound on acetylcholinesterase and α-glycosidase enzymes were evaluated. Another aim of this study was to compare the inhibitory effects of sesamol to acarbose for α-glycosidase enzyme and tacrine for acetylcholinesterase (AChE). Sesamol exhibited non-competitive inhibition for both metabolic enzymes. IC50 values for AChE and α-glycosidase enzymes were calculated as 86.63 nM and 99.00 nM, respectively. On the other hand, Ki values were calculated as 46.68 nM and 75.33 nM for AChE and α-glycosidase enzymes, respectively. According to the obtained results showed effective inhibition at low concentrations.
- MakaleYalnız künye2019Determining tourists’ propensity to consume innovative cuisine: the case of molecular cuisine
Akyürek, suat; Kızılcık, onur
In this research, which was carried out in order to obtain findings that will contribute to determine touristic product development and promotion strategies of tourism establishments serving for food and beverage industry, tourists’ propensity to consume molecular cuisine were reviewed. Moreover, it was tested whether or not there was difference between tourists’ propensity to consume molecular cuisine according to some socio-demographic variables in order to obtain indicative findings for tourism marketers within the scope of demographic segmentation which is among the market segmentation strategies. The data obtained from the research was reviewed and then reliability analysis, frequency analysis, t test, and one-way variance analysis were performed on the data. Finally, theoretical and practical implications of this study were discussed.
- MakaleYalnız künye2018A New Nomogram Proposal to Determine Concrete Compressive Strength by Combined Nondestructive Testing Methods
Bingöl, Şinasi; Çavdar, Ahmet
Concrete is the most widely used construction material in contemporary construction technology. In particular, it holds an important place in the building industry in the world. Since concrete is a nonhomogeneous material, determining the strength of concrete accurately is quite difficult. In this respect, to check the mechanical properties of concrete in-situ, nondestructive test (NDT) methods can be used. They are useful as they do not damage concrete; however, these test results are sometimes deceptive. To reduce these deceptive results, destructive test methods were proposed to increase the accuracy of nondestructive methods. The objective of this study is to determine the strength of concrete with different characteristic strengths using destructive and NDT methods, and to establish new relationships between the compressive strength of concrete and Schmidt rebound values, and ultrasonic wave velocities. For this purpose, 101 concrete cube samples were prepared. After 7 and 28 days of curing, Schmidt rebound and ultrasonic wave velocity tests were applied as NDT methods. New formulations and graphs were established by carrying out a multiple regression analysis between the ultrasonic wave velocities, Schmidt rebound values, and compressive strengths. Thus, a new combined NDT method was developed with a nomogram. Furthermore, the applicability and accuracy of the formula and graph obtained were investigated by comparing the results of core samples from existing structures. The most important findings obtained from the study are summarized below. The concrete strength can be determined with nondestructive formulas obtained with an accuracy of 85%. High strength concrete cube samples are obtained in-house with 1.6% deviation, and core samples in-situ can be obtained with 7.3% deviation with the newly developed NDT nomogram. These test results show that the newly developed NDT formulas in this study are a very good alternative for determining concrete strength in-situ.
- MakaleYalnız künye2018Adsorption of Cu(II) ions from aqueous solution by hazelnut husk activated carbon prepared with potassium acetate
Imamoglu, Mustafa; Ozturk, Asuman; Aydın, Şeyma; Manzak, Aynur; Gündoğdu, Ali; Duran, Celal
Hazelnut husk (HH), an agricultural waste, was converted to carbonaceous material by chemical activation using potassium acetate. The produced activated carbon (KAHHAC) was characterized by FTIR, SEM, N2 adsorption–desorption experiments, CHN elemental analysis, and determination of moisture, ash, and point of zero charge. KAHHAC was used for the batch adsorption of Cu(II) ions from aqueous solutions. Optimum pH and contact time were found to be 5.0 and 240 minutes, respectively. The adsorption equilibrium data were described well by the Langmuir equation providing 105.3 mg g−1 Cu(II) adsorption capacity. The pseudo-second-order model successfully described the kinetic of Cu(II) adsorption by KAHHAC. The adsorbed Cu(II) onto KAHHAC was completely desorbed by 0.5 M nitric acid. In conclusion, HH activated carbon (AC) produced by the potassium acetate activation method is a very useful and efficient sorbent material for the removal of Cu(II) from aqueous solution.
- Derleme MakaleAçık Erişim2018Late Cretaceous arc igneous activity: the Eğrikar Monzogranite example
Sipahi, F.; Kaygusuz, A.; Saydam Eker, Ç.; Vural, A.; Akpınar, İ.
The geochemical and Sr–Nd–Pb isotope properties, as well as the Laser Ablation Inductively Coupled Plasma and Mass Spectrometry (LA-ICP-MS) U–Pb zircon age, of Eğrikar Monzogranite in the eastern Pontides, are primarily investigated in this study with the aim of determining its magma source and geodynamic evolution. The U–Pb zircon age obtained from Eğrikar Monzogranite is 78 ± 1.5 Ma, thereby reflecting the age of monzogranite. The I-type Eğrikar Monzogranite comprises quartz, plagioclase (An35–45), orthoclase, muscovite, and biotite. The geochemical analyses of the Eğrikar Monzogranite indicate being medium K calc-alkaline, peraluminous, and resembling magmatic arc granite. The Eğrikar Monzogranite is enriched in large ion lithophile elements and light rare earth elements relative to high field strength elements. Chondrite-normalized rare earth element patterns have concave upward shapes (LaN/YbN 2.47–8.58) with pronounced negative Eu anomalies (EuN/Eu* = 0.29–0.65). Initial εNd(i) values vary between 1.85 and 2.18 and initial 87Sr/86Sr values between 0.7048 and 0.7067. Fractionation of plagioclase, hornblende, and apatite played an important role in the evolution of Eğrikar Monzogranite. The crystallization temperatures of the melts ranged from 770°C to 919°C based on zircon and apatite saturation temperatures. The geochemical and isotopic data suggest being generated by the partial melting of mafic lower crustal sources.
- MakaleAçık Erişim2018Purification and selected biochemical properties of peroxidase from cress (Lepidium sativum sub sp. sativum)
Altay, Ahmet; Koktepe, Tubanur; Durmaz, Lokman; Topal, Fevzi; Gülçin, İlhami; Köksal, Ekrem
Cress (Lepidium sativum) is an annual herb from Brassicaceae family, and in some regions. It is known as peppergrass, garden cress, garden pepper-cress, pepperwort, or poor man’s pepper. Cress is an important medicinal plant in some countries including Turkey. This plant has major scientific and therapeutic significance. Peroxidase (POD, E.C.1.11.1.7) is an oxidor-eductase enzyme produced by a number of organisms. In this study, POD enzyme was purified from cress by ammonium sulphate precipitation, gel filtration, and CM-Sephadex ion-exchange chromatographies. K m and V max values were calculated from the Lineweaver-Burk graph for H 2 O 2 and guaiacol substrates and the substrate specificity of POD was investigated. The results showed that substrate specificity of H 2 O 2 is better than substrate specificity of guaiacol for this enzyme. The inhibition effects of three cations (Al 3+ , Cu 2+ , and Cr 3+ ) and one organic compound of cetyl trimethylammonium bromide were performed and their inhibition types were determined. Finally, optimum pH, optimum temperature, optimum ionic strength, and stable pH were determined.
- MakaleYalnız künye2017Stability Estimates for Solution of Neumann-Type Overdetermined Elliptic Problem
Ashyralyyev, Charyyar
This paper addresses estimation of the solution of inverse problem for the elliptic type equation with second kind boundary conditions and Neumann-type overdetermination at the interior point. We prove various estimates for the solution of this identification problem. Then, the first order accuracy stable difference scheme is studied. The stability, almost coercive stability, and coercive stability inequalities for its solution are obtained. The theoretical results can be applied to investigate identification problems for multidimensional elliptic equation with different kind of boundary conditions.
- MakaleYalnız künye2017Isolation and Characterization of Thermophilic Bacteria from Geothermal Areas in Turkey and Preliminary Research on Biotechnologically Important Enzyme Production
Baltaci, Mustafa Ozkan; Genc, Berna; Arslan, Sumeyya; Adiguzel, Gulsah; Adiguzel, Ahmet
In this study, the isolation, identification and characterization of the thermophilic bacteria from different hot springs in Turkey were carried out by conventional (morphological, physiological and biochemical tests) and molecular methods (fatty acid methyl esters, GTG5-PCR and 16S rRNA sequencing). These thermophilic bacteria were then tested for their capability to produce enzymes such as lipase, protease, amylase and cellulase. O20 strain is a novel species according to identification studies. All of its isolates were capable of producing industrially valuable enzymes based on screening. In fact, most of them could produce at least two of these enzymes.
- MakaleAçık Erişim2016Investigation of Hydroxymethylfurfural Formation in Herle
Baltacı, Cemalettin; Ilyasoglu, Huri; Gundogdu, Ali; Ucuncu, Osman
Mulberry pestil and köme are Turkish traditional foods made from herle. Browning leads to quality losses in the herle, and its products. In this study, the effect of thermal treatment on the hydroxymethylfurfural formation and color values in the herle was evaluated. The herle samples were kept at different temperatures (60–110°C) and times (2–6 h). The hydroxymethylfurfural formation was found to increase with increasing time and temperature. The legal limit for hydroxymethylfurfural in the pestil (50 mg/kg) was exceeded at temperatures above 90°C. The lightness (L* value) of the sample decreased with the thermal treatment, indicating browning.
- MakaleYalnız künye2016Concentrations of elements in Lias coals from the eastern Black Sea Region, NE-Turkey
Eker, Çiğdem Saydam; Akpınar, İbrahim; Sipahi, Ferkan; Yapıcı, Ejder
ABSTRACT: The element contents and organic matter-element relation between Lias-aged coals exposed in four fields in Gümüşhane and Bayburt were investigated. In general, fixed carbon and gross calorific values of the Edire and Balkaynak coals are higher than Güvercinlik and Çerçi coals. The highest ash yields were observed in the Çerçi coals. The concentrations of Mg, P, Ca, Mo, Y, Ni, U, Zn, Ga, Ba, W, Sr, Ta, and Be of the analysed coals are positively correlated with ash yield, indicating an organic affinity. The Lias-aged coals located in Gümüşhane and Bayburt are low-rank coals.
- MakaleYalnız künye2016Effects of organic solid cattle manure application on nutritive value of winter cereal forages
Yolcu, H.; Gullap, M.K.; Yildirim, M.; Lithourgidis, A.; Deveci, M.
Nutritive value of winter cereal forages is one of interested subjects of farmers for animal feeding. Field experiments were established in 2007–2008 and 2008–2009 growing seasons in northeast Turkey to investigate the effect of organic solid cattle manure application (0, 10 and 20 Mg ha−1 yr−1) on nutritive value of three annual cereals for forage. The winter cereal forages were: wheat (Triticum aestivum L.), oat (Avena sativa L.) and rye (Secela cereale L.). ADF (acid detergent fiber), NDF (neutral detergent fiber) CP (crude protein), nitrogen, phosphorus, potassium, sulfur, calcium, copper, iron, magnesium, manganese, sodium, zinc and boron (N, P, K, S, Ca, Cu, Fe, Mg, Mn, Na, Zn and B) concentrations were researched in this study. Wheat had the highest CP, N, Ca, Cu, Na and Zn concentration, whereas oat had the lowest ADF and NDF and the highest K, Fe and Mn concentrations. The greatest Mg and P concentrations were determined in rye. Organic solid cattle manure applications had no effect on N and CP contents, but it decreased ADF and NDF contents. However, in most cases it positively affected the P, B, Cu, Fe, Mg and Na concentrations, whereas it decreased K, Ca, Mn and Zn concentrations. The results showed that wheat and oat are more nutritive species than rye in terms of animal feeding and the organic solid cattle manure, in some cases increased the nutritive values of wheat, oat and rye under organic agriculture conditions.
- MakaleYalnız künye2015Effect of domestic cooking methods on antioxidant capacity of fresh and frozen kale
Ilyasoʇlu, Huri; Burnaz, Nesibe Arslan
The aim of this study was to evaluate the changes in the antioxidant capacity of fresh and frozen kale during domestic cooking methods (e.g., boiling, microwaving, and steaming). The antioxidant activities of the samples were measured using three in vitro assays (1,1-diphenyl-2-picrylhydrazyl assay, 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid assay, and ferric reducing antioxidant power assay). The steaming treatment was found to be the best cooking method to retain antioxidant compounds, followed by the microwaving and boiling treatments. The frozen uncooked samples exhibited a higher antioxidant capacity than the fresh, uncooked samples, indicating that the freezing process could enhance the antioxidant capacity of the kale.
- MakaleYalnız künye2015Synthesis, X-Ray Structural, Characterization, NLO, MEP, NBO, and HOMO-LUMO Analysis Using DFT Study of Co(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) Dihydrate
Kaya, Elif Çelenk; Demircioʇlu, Zeynep; Kaya, Afşin Ahmet; Büyükgüngör, Orhan
A suitable single crystal of Co(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) dihydrate, formulated as C30H38N4O14Co,(I). According to experimental data, the complex can be characterized in the solid state as mononuclear, with a distorted octahedral stereochemistry. The distorted octahedral stereochemistry adopted by the complex was further confirmed by the x-ray structure analysis of current study, which consists of a six-coordinate Co atom in a distorted octahedral environment constructed from two N atoms and four O atoms. The title compound which has been characterized by IR, UV, and single crystal X-ray diffraction analysis at 296 K crystallizes in the monoclinic space group C 2/c with a = 27.9402(15) Å, b = 8.6005(3)Å, c = 14.7921(9)Å, α = 90°, β = 108.849(4)°, and γ = 90°, Z = 4. The molecular structure and geometry have also been optimized using B3LYP density functional theory method employing the 6-31G (d) basis set. The molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, nonlinear optical properties (NLO), and natural bond analysis (NBO) for the title molecule are also described from the computational process.
- MakaleAçık Erişim2015Simultaneous separation and preconcentration of Cd(II), Co(II), and Ni(II) ions in environmental samples by carrier element-free coprecipitation method prior to their flame atomic absorption spectrometric determination
Duran, Celal; Ozdes, Duygu; Akcay, Hakki Turker; Serencam, Huseyin; Tufekci, Mehmet
ABSTRACT: In the present study, Cd(II), Co(II), and Ni(II) ions were separated and preconcentrated via carrier element-free coprecipitation (CEFC) method by using an organic coprecipitating agent, 1,2-bis-(2-tosyl ethoxy) benzene (BTEB), prior to their flame atomic absorption spectrometric (FAAS) detections. The experimental conditions were optimized in terms of pH of the aqueous solution, BTEB amount, standing time, centrifugation rate and time, and sample volume. Under the optimum experimental conditions, the detection limits for Cd(II), Co(II), and Ni(II) ions were found to be 0.13, 0.67, and 0.46 μg L−1, respectively, and the relative standard deviations for the analyte ions were found to be lower than 4.0%. The accuracy of the method was tested by analyzing certified reference material and spike tests. The method was applied to determine the levels of Cd(II), Co(II), and Ni(II) ions in sea and stream water, macaroni, red lentil, and cracked wheat samples.
- MakaleAçık Erişim2014Assessment of kinetics, thermodynamics, and equilibrium parameters of Cu(II) adsorption onto Rosa canina seeds
Serencam, Huseyin; Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri
Rosa canina seeds (RCS) is considered as a low-cost and promising adsorbent in removal of metal ions; hence, in the present study, we aimed to test the adsorptive removal of Cu(II) ions from aqueous solutions by utilizing RCS in a batch process. After characterization of RCS by using several techniques, the effects of various experimental parameters such as initial pH of aqueous solution, contact time, initial Cu(II) concentration, RCS concentration, temperature, and electrolyte concentration were studied upon the adsorption process. The desorption conditions of Cu(II) ions from the loaded RCS were also evaluated. Maximum Cu(II) adsorption was found to occur at pH 6.0 and the equilibrium was established after 60 min of contact time. The adsorption isotherms were described by means of Langmuir, Freundlich, Temkin, and Dubinin Radushkevich models. The adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models and the adsorption data were well described by the pseudo-second-order model. Thermodynamic parameters such as the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes were also evaluated and it has been found that the adsorption process was feasible, spontaneous, and endothermic in the temperature range of 278-313 K.
- MakaleAçık Erişim2014Kinetics, thermodynamics, and equilibrium evaluation of adsorptive removal of methylene blue onto natural illitic clay mineral
Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri; Avan, Hilal; Bicer, Burcin
The natural illitic clay mineral (NICM) has been used as a low cost and highly effective adsorbent in the removal of a toxic cationic dye, methylene blue (MB), from aqueous solution by a batch adsorption technique. The effects of experimental parameters such as initial pH of the aqueous solution, contact time, initial MB concentration, adsorbent concentration, ionic strength, and temperature were studied in detail upon the adsorption process. The process was found to be independent of initial solution pH and the adequate equilibrium time for the adsorption of MB onto NICM was only 60 m. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and showed a good fit with both the Langmuir and Freundlich isotherm models. The monolayer adsorption capacity of NICM was found to be 24.87 mg g-1 by using Langmuir isotherm model. The kinetics of the adsorption were tested using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results showed that the adsorption of MB onto NICM proceeds according to the pseudo-second-order model. Thermodynamic parameters indicated that the present adsorption process was feasible, spontaneous, and endothermic in nature.