Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2023Characterization of the Adsorption Mechanism of Cadmium(II) and Methylene Blue upon Corncobs Activated Carbon
Gundogdu, Ali; Bozbeyoglu, Pinar; Imamoglu, Mustafa; Baltaci, Cemalettin; Duran, Celal; Bulut, Volkan N.
A promising new activated carbon (AC) was produced from corncobs (CCs) by boric acid-based chemical activation to remove methylene blue (MB) as an organic pollutant and cadmium ions (Cd2+) as an inorganic pollutant from aqueous solutions. After the produced activated carbon (CCs-AC) was characterized, the adsorption mechanism of CCs-AC, which is one of the most interesting topics in the literature, was the primarily focus. The possible adsorption mechanisms of Cd2+ and MB on CCs-AC from aqueous solutions are discussed with respect to pH, thermodynamic values, and regeneration parameters. The results show that the adsorption of Cd2+ on CCs-AC was favorable at pH values higher than 4. In contrast, the adsorption process was almost pH-independent for MB. Variation of pH showed that the adsorption of Cd2+ on CCs-AC primarily occurs by electrostatic interaction. However, MB adsorption may also involve pi-pi dispersion forces and partial hydrogen bonding. The Cd2+ adsorbed on CCs-AC was quantitatively desorbed by HCl, whereas MB was not desorbed quantitatively by any solution. While a temperature increase has a positive effect on the adsorption of both methylene blue and Cd2+, the thermodynamic results show that MB adsorption is primarily chemisorption (Delta H of 24.28 kJ/mole), while Cd2+ adsorption is mostly physisorption (Delta H of 7.20 kJ/mole). Using Langmuir adsorption isotherms, the MB adsorption capacity of CCs-AC, which primarily has a microporous structure, was 0.88 mmol/g, while the Cd2+ adsorption capacity was 1.28 mmol/g.
- MakaleAçık Erişim2022Atık Sulardan Cd(II) İyonlarının Adsorpsiyonu için Doğal Adsorban Olarak Kızılçam (Pinus Brutia Ten.) Talaşının Performansının Değerlendirilmesi
Duran, Celal; Ozdes, Duygu; Torun, Erdem
Bazı ağır metallerin çok düşük derişimlerde bile vücuda alınımı, kan bileşiminin bozulmasına, merkezi sinir sistemi fonksiyonlarında azalmaya ve akciğer, böbrek ve karaciğer gibi organlarda hasarlara neden olabilir. Bu nedenle ağır metal iyonlarının, alıcı ortama verilmeden önce sulardan ve atık sulardan uzaklaştırılması gerekmektedir. Bu çalışmada, Cd(II) iyonlarının sulardan ve atık sulardan adsorpsiyon tekniğiyle gideriminde etkili ve ucuz bir adsorban olarak kızılçam (Pinus Brutia Ten.) talaşının kullanılabilirliği değerlendirilmiştir. Adsorpsiyon deneylerinde kullanılan kızılçam talaşı fiziksel veya kimyasal herhangi bir ön işleme tabi tutulmadan doğal olarak kullanılmıştır. Kızılçam talaşı, çeşitli yöntemlerle karakterize edildikten sonra adsorpsiyon verimi üzerine başlangıç sulu çözelti pH’ı, denge süresi, adsorban miktarı ve başlangıç Cd(II) derişimi gibi deneysel faktörlerin etkileri incelenmiş ve ayrıca endüstriyel atık sularda Cd(II) iyonlarıyla birlikte bulunabilecek bazı tuzların etkileri araştırılmıştır. Elde edilen sonuçlardan optimum pH 6.0 ve denge süresi 240 dk olarak belirlenmiştir. Mekanizma hakkında fikir edinmek için elde edilen verilere izoterm modelleri (Langmuir ve Freundlich) uygulanmıştır. Kızılçam talaşının maksimum adsorpsiyon kapasitesi Langmuir izoterm modeli kullanılarak 11.88 mg g-1 olarak hesaplanmıştır. Sonuç olarak kızılçam talaşının atık sulardan Cd(II) iyonlarının uzaklaştırılmasında etkili bir adsorban olarak kullanılabileceği ortaya konulmuştur.
- MakaleYalnız künye2022Karaağaç (Ulmus glabra) ve Dut (Morus alba) Talaşı ile Sulu Çözeltilerden Adsorpsiyon Yöntemiyle Rodamin 6G Giderimi
Duran, Celal; Reis, Ceyhun; Ozdes, Duygu
Bu çalışmada, canlı metabolizmasında toksik etki gösteren katyonik yapıda boyarmadde olan Rodamin 6G’nin (R6G) sulardan ve atık sulardan uzaklaştırılmasında doğal karaağaç (Ulmus glabra) (UGT) ve dut (Morus alba) (MAT) talaşlarının ucuz ve etkili adsorbanlar olarak kullanılabilirliği araştırılmıştır. R6G’nin gideriminde adsorban olarak literatürde ilk defa bu çalışmada kullanılan UGT ve MAT çeşitli yöntemlerle karakterize edilmiştir. Adsorpsiyon deneyleri kesikli sistemle yürütülmüş olup, R6G’nin adsorpsiyon verimi üzerine başlangıç sulu çözelti pH’ı, denge süresi ve başlangıç R6G konsantrasyonu gibi deneysel parametrelerin etkileri incelenmiştir. R6G’nin her iki adsorban üzerine adsorpsiyonu için optimum sulu çözelti pH’ının 7.0 ve denge süresinin 180 dakika olduğu görülmüştür. Adsorpsiyon mekanizmasının aydınlatılabilmesi için elde edilen deneysel verilere çeşitli kinetik (yalancı birinci ve ikinci mertebeden kinetik model ile parçacık içi difüzyon modeli) ve izoterm modelleri (Langmuir, Freundlich, Temkin ve Dubinin-Radushkevich) uygulanmıştır. Adsorpsiyon kinetiğinin, ikinci mertebeden kinetik modeli takip ettiği ve deneysel verilerin hem Langmuir hem de Freundlich izoterm modellerine iyi bir uyum gösterdiği tespit edilmiştir. UGT ve MAT’in maksimum adsorpsiyon kapasitesi Langmuir izoterm modeli kullanılarak sırasıyla 50.5 ve 31.8 mg g-1 olarak hesaplanmıştır. Yapılan çalışma sonucunda karaağaç ve dut talaşının boyarmadde gideriminde kullanılacak etkili ve düşük maliyetli alternatifler olabileceği görülmüştür.
- MakaleAçık Erişim2022Insights into brewed tea waste as a green and low-priced adsorbent for solid-phase extraction of Cd(II) ions: isotherm, kinetic, and artificial neural network approach
Ozdes, Duygu; Tilki, Nida; Seker, Serdal; Duran, Celal
In the present research, brewed tea waste (BTW) was utilized as a green, low-priced, and abundant adsorbent for separation/preconcentration of Cd(II) ions through solid-phase extraction method from water and foods for the first time. BTW was applied as a natural adsorbent, without using any chelating agent to bind Cd(II) ions or any chemical reagent for its modification. A three-layer artificial neural network model using backpropagation algorithm was utilized to explicate a prediction model for the extraction performance of Cd(II) ions by selecting the input parameters as solution pH, quantity of BTW, sample volume, eluent concentration and volume, and equilibrium time for desorption. The preconcentration factor, relative standard deviation, and detection limit were attained as 100, 3.03%, and 0.56 µg L−1, respectively. It was decided that the Langmuir isotherm model is acceptable to characterize the retention of Cd(II) ions on BTW. This result pointed out that the active binding sites on the BTW surface are homogeneously distributed. Adsorption capacity of BTW was achieved as 41.5 mg g−1 which is higher than several expensive and difficult-to-prepare adsorbents. Adsorption kinetics was elucidated by pseudo-second order kinetic model. After confirmed the accuracy of the method with spike/recovery studies, it was employed for Cd(II) determination in water (stream and sea water) and food (eggplant, lettuce, parsley, apple, and apricot) samples with high accuracy. The inferences of the study proved that the BTW offers a magnificent application prospect in the extraction of Cd(II) ions.
- MakaleYalnız künye2021Preparation of melon peel biochar/CoFe2O4 as a new adsorbent for the separation and preconcentration of Cu(II), Cd(II), and Pb(II) ions by solid-phase extraction in water and vegetable samples
Ozdes, Duygu; Duran, Celal
The present research describes the successful preparation of melon peel biochar modified with CoFe2O4 (MPBC/CoFe2O4) followed by its usage as a new sorbent to separate, preconcentrate, and determine the toxic heavy metal ions by magnetic solid-phase extraction. The metal ion desorption was performed by 0.1 M HCl solution with a volume of 5.0 mL. Flame atomic absorption spectrometry (FAAS) was utilized for detection of the analyte levels. SEM–EDX, TEM, XRD, and FTIR techniques were carried out to illuminate the structure of MPBC/CoFe2O4. The fundamental variables affecting the adsorption and elution efficiencies of the analyte ions including solution pH, MPBC/CoFe2O4 amount, type and concentration of eluent, adsorption and desorption equilibrium time, and sample volume were optimized. The detection limits were calculated as 0.41, 1.82, and 3.16 µg L−1 for Cu2+, Cd2+, and Pb2+ ions, respectively, with the relative standard deviation of lower than 4.2%. There were no substantial interference effects on the analyte ion recovery due to the presence of foreign ions at high levels. Five minutes of contact time was adequate to attain the adsorption equilibrium. The adsorption capacity of MPBC/CoFe2O4 was obtained as 106.4, 65.4, and 188.7 mg g−1 for Cu2+, Cd2+, and Pb2+ ions, respectively, by utilizing Langmuir isotherm model. The pseudo-second order model is favorable to identify the adsorption kinetics. The method was validated by spike/recovery test, and then, it was successfully implemented to determine the aforementioned analyte levels in sea and stream water, pepper, black cabbage, eggplant, and tomato samples.
- MakaleAçık Erişim2020İçme suyu arıtma tesisi atık çamuru üzerinemetilen mavisi adsorpsiyonu ve yapay sinir ağlarıile modellenmesi
Öztürk, Nurcan; Senturk, Hasan Basri; Gundogdu, Ali; Duran, Celal
Bu çalışmada içme suyu arıtma tesislerinde arıtım aşamaları sonucu oluşan İçme Suyu Arıtma Tesisi Atık Çamurunun (İSATAÇ), atık sularda organik kökenli bir kirletici (boyar madde) olan Metilen Mavisinin uzaklaştırılmasında adsorban olarak kullanılabilirliği araştırılmıştır. Adsorpsiyon çalışmalarında kullanılan İSATAÇ fiziksel ya da kimyasal ön işleme tabi tutulmamıştır. Öncelikle İSATAÇ’ın nem, yoğunluk, uçucu madde, sabit karbon, kül tayini yanı sıra elementel, SEM, FT-IR, XRD, XRF ve TGA/DTA analiz gibi çeşitli analitik işlemlerle karakterize edilmiştir. Sonrasında adsorpsiyon deneyleri kesikli sistemle gerçekleştirilmiş ve İSATAÇ’ın sulu çözeltiden bu kirletici türü uzaklaştırma potansiyeli denge, kinetik ve termodinamik parametreler açısından incelenmiştir. Metilen mavisinin uzaklaştırılmasında Langmuir izoterm modelinden elde edilen maksimum adsorplama kapasitesi 62,50 mg g-1 olarak tespit edilmiştir. Bazı deneysel parametrelerin İSATAÇ üzerinde Metilen Mavisi adsorpsiyonuna etkileri göz önüne alınarak Yapay Sinir Ağı (YSA) modeli geliştirilmiş ve İSATAÇ’ın atık sulardan organik kirleticilerin uzaklaştırılmasında kullanılabileceği sonucuna varılmıştır.
- MakaleAçık Erişim2020Adsorption Of Methylene Blue from Aqueous Solution with Sulfuric Acid Activated Corn Cobs: Equilibrium, Kinetics, and Thermodynamics Assessment
Baltaci, Cemalettin; Gundogdu, Ali; Duran, Celal; Bozbeyoglu, Pinar
Three adsorbents with different characteristics were produced in this study by activation of sulfuric acid with different concentrations, from corn (Zea mays L.) cobs, which is an agricultural waste by-product resulting from harvesting. After characterization by the parameters such as Boehm titration, determination of pH-pHpzc, and methylene blue – iodine number, and IR analysis, their methylene blue adsorption potentials from aqueous medium were investigated based on equilibrium, kinetics, and thermodynamics evaluations. This study aims to examine the effects of relatively dilute and concentrated acids on the activation process and to gain an economic value to waste materials through the production of a new adsorbent. It was observed that the initial solution pH did not have a significant effect on the adsorption efficiency. The adsorption process reached the equilibrium at the end of the first 120 minutes, and the kinetic data fit the pseudo-second-order kinetic model. Langmuir adsorption capacity (295.5 mg/g) of the adsorbent produced by activating with 50% sulfuric acid was found higher than those produced with 75% and 98% acids. An increase in ambient temperature effected the adsorption positively. As a result, in this study, very low-cost adsorbents were produced from the waste by-product corn cobs, and a new approach was proposed for cleaning wastewater containing dyestuffs.
- MakaleYalnız künye2019Assessment of Heavy Metal Contents of Mulberry Samples (Fruit, Leaf, Soil) Grown in Gumushane Province; [Beurteilung des Schwermetallgehaltes bei Maulbeeren (Frucht, Blatt, Boden) aus der Region Gumushane]
Kalkisim, Ozgun; Ozdes, Duygu; Baltaci, Cemalettin; Duran, Celal
The present study aims to identify the heavy metal contents of white mulberry (Morus alba L.) and black mulberry (Morus nigra L.) that are grown in the city center of Gumushane province and its neighboring counties. Heavy metal analyzes were performed in the fruits, leaves and soils of the plants. The control samples, on the other hand, were collected from the mulberry trees located 3 km away from the highway where the vehicle traffic and industrial activities are at their lowest. Sample collection was performed twice a year, namely during the ripening period and fully ripening period of the fruits. The analyses of the heavy metals were performed by using inductively coupled plasma-mass spectrophotometry (ICP-MS). The obtained results were compared with the acceptable limits of heavy metal for humans as established by the World Health Organization (WHO), Turkish Food Codex (TFC) and the literature and an opinion was submitted as to whether they present any risk in terms of human health. When the available data is evaluated, the mulberries grown in Gumushane province, were found to have presented a health risk in terms of Pb, Cd, Ni, Cu, Zn, Mn and Co metals.
- 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.
- MakaleYalnız künye2018Modeling of Co(II) adsorption by artificial bee colony and genetic algorithm
Öztürk, Nurcan; Sentürk, Hasan Basri; Gündogdu, Ali; Duran, Celal
In this work, it was investigated the usability of artificial bee colony (ABC) and genetic algorithm (GA) in modeling adsorption of Co(II) onto drinking water treatment sludge (DWTS). DWTS, obtained as inevitable byproduct at the end of drinking water treatment stages, was used as an adsorbent without any physical or chemical pre-treatment in the adsorption experiments. Firstly, DWTS was characterized employing various analytical procedures such as elemental, FT-IR, SEM-EDS, XRD, XRF and TGA/DTA analysis. Then, adsorption experiments were carried out in a batch system and DWTS's Co(II) removal potential was modelled via ABC and GA methods considering the effects of certain experimental parameters (initial pH, contact time, initial Co(II) concentration, DWTS dosage) called as the input parameters. The accuracy of ABC and GA method was determined and these methods were applied to four different functions: quadratic, exponential, linear and power. Some statistical indices (sum square error, root mean square error, mean absolute error, average relative error, and determination coefficient) were used to evaluate the performance of these models. The ABC and GA method with quadratic forms obtained better prediction. As a result, it was shown ABC and GA can be used optimization of the regression function coefficients in modeling adsorption experiments.
- MakaleYalnız künye2018Evaluation of Pomological and Morphological Characteristics and Chemical Compositions of Local Pear Varieties (Pyrus communis L.) Grown in Gumushane, Turkey; [Pomologische und morphologische Eigenschaften sowie Inhaltsstoffe lokaler Birnensorten (Pyrus communis L.) in Gumushane (Türkei)]
Kalkisim, Ozgun; Okcu, Zuhal; Karabulut, Besim; Ozdes, Duygu; Duran, Celal
The aim of the present research was to investigate the fruit quality of twenty different local pear varieties (Pyrus communis L.), namely Ahlat, Ankara, Arpa, Bıldırcın, Çermai, Cinci, Gelin Boğan, Hacı Hamza, Hahır, Kabak, Kızıl, Kokulu, Mehrani, Menendi, Sulu, Şalgam, Tokat Sultanı, Turşu, Yaz, and Yaz Meyriği, grown in Gumushane province in terms of pomological and morphological characteristics and chemical compositions. The fruit mass, fruit width and length, fruit stem thickness and length, fruit kernel width and length, hardness of pulp, number of seeds, leaf width and length, leaf stem length and thickness, and water soluble dry matter (WSDM) of the pear fruits have been determined as pomological and morphological characteristics. On the other hand, the chemical compositions of the pear varieties have been evaluated in terms of protein, ash, sucrose, fructose, glucose, total sugar, titratable acidity, moisture, and mineral element levels. Both pomological and morphological results demonstrated that the local pear varieties are important in terms of rehabilitation studies and detailed selection studies on these local varieties should be performed. The chemical analyses result of the pear varieties revealed that there is no component that may be harmful to human health when consumed, and also these varieties contains the necessary amount of mineral elements.
- MakaleAçık Erişim2016Separation and preconcentration of Pb(II) and Cu(II) ions via carrier element-free coprecipitation using an acetohydrazide derivative
Tümay, Süreyya Oǧuz; Yazar, Murat; Ozdeş, Duygü; Bektaş, Hakan; Duran, Celal
A new method based on the combination of carrier element-free coprecipitation and flame atomic absorption spectrometric determination has been investigated for simultaneous separation and preconcentration of Pb(II) and Cu(II) ions in some environmental solid and liquid samples. The 2-f3-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-ylg -N'-(phenylmethylene) acetohydrazide (MITA) was utilized as an organic coprecipitating agent without using a carrier element for coprecipitation of the analyte ions. The effects of experimental conditions including aqueous solution pH, MITA quantity, sample volume, standing time, and centrifugation rate and time were investigated in detail and optimized. The influences of some foreign ions were also evaluated on the quantitative recoveries of the analyte ions. The preconcentration factors were 125 for both analyte ions. The detection limits were 1.32 μgL-1 and 0.47 μg L-1 for Pb(II) and Cu(II) ions, respectively, and the relative standard deviations (RSDs) were lower than 4% for both analyte ions. After the accuracy of the method was checked, it was applied to sea and stream water as liquid samples and waste tea and tobacco as solid samples to determine the levels of Pb(II) and Cu(II) ions.
- MakaleYalnız künye2016A novel carrier element-free co-precipitation method for separation/preconcentration of lead and cadmium ions from environmental matrices
Bulut, Volkan Numan; Demirci, Hamit; Ozdes, Duygu; Gundogdu, Ali; Bekircan, Olcay; Soylak, Mustafa; Duran, Celal
A new separation and pre-concentration method was presented in this study for two trace heavy metal ions, lead (Pb2+) and cadmium (Cd2+) from aqueous solutions, based on a carrier element free co-precipitation (CEFC) method using a triazole derivate, 3-(4-tert-butylphenyl)−5-phenyl-4-(2-hydroxy-5-methoxybenzylamino)−4H-1,2,4-triazole as an organic co-precipitating agent. The method was optimized with some analytical parameters which affect the quantitative recoveries of study metals. According to the results, optimum pH of solution, quantity of co-precipitating agent, centrifugation and incubation time, and sample volume were determined as 6.0, 1.5 mg, 10 min, and 10 min, and 100 mL, respectively. In addition, no significant matrix interferences were observed over the recovery of the metal ions. For analytical figure of merit, RSD values of the method were found as 5.7 and 4.8 for Pb2+ and Cd2+, respectively. LOD values were also calculated as 2.0 µg L−1 for Pb2+ and 0.2 µg L−1 for Cd2+. The accuracy of method was checked with spiked/recovery tests and analysis of a standard reference material. The developed method was finally applied to the real liquid/solid samples under the optimum conditions.
- MakaleAçık Erişim2015Selective separation, preconcentration and determination of Pd(II) ions in environmental samples by coprecipitation with a 1,2,4-triazole derivative
Ozdes, Duygu; Duran, Celal; Serencam, Huseyin; Sahin, Deniz; Gundogdu, Ali; Soylak, Mustafa
A simple, sensitive, facile and low cost methodology, combined with flame atomic absorption spectrometry (FAAS), was employed to evaluate the selective separation and preconcentration of Pd(II) ions in environmental samples by using a triazole derivative as an organic coprecipitating agent without a carrier element. The developed method was systematically investigated in different set of experimental parameters that influence the quantitative recovery of Pd(II) ions. The accuracy of the method was tested by analyzing certified reference material and spike tests. The developed coprecipitation procedure has been applied to road dust, anodic slime, industrial electronic waste materials and water samples to determine their Pd(II) levels.
- MakaleYalnız künye2015Equilibrium, kinetics, and thermodynamic evaluation of mercury (II) removal from aqueous solutions by moss (Homalothecium sericeum) biomass
Ozdes, Duygu; Duran, Celal
In the present research, Homalothecium Sericeum was utilized for the first time as an effective and readily available adsorbent in removal of Hg(II) ions from aqueous solutions through a batch adsorption technique. The effects of initial solution pH, contact time, initial Hg(II) and adsorbent concentration, temperature, and ionic strengths were evaluated on the removal efficiency of Hg(II) ions, after being characterized of H. sericeum by different techniques. The maximum Hg(II) adsorption was obtained as 128.2 mg g-1 at initial pH 6.0 with an equilibrium time of 60 min, adsorbent dosage of 5.0 g L-1 and initial Hg(II) concentration range of 50-750 mg L-1. The adsorption behaviors of Hg(II) ions onto H. sericeum were investigated in terms of kinetics (pseudo-first order, pseudo-second order, and intraparticle diffusion models), isotherms (Langmuir, Freundlich, and Dubinin Radushkevich models), and thermodynamics evaluation. Both the Langmuir and Freundlich isotherm models were found to be suitable to describe the adsorption equilibrium while the adsorption kinetics followed by the pseudo-second order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the adsorption of Hg(II) ions onto H. sericeum was feasible, spontaneous, and endothermic in nature.
- 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.
- MakaleYalnız künye2014Assessment of kinetics, thermodynamics and equilibrium parameters of Cr(VI) biosorption onto Pinus brutia Ten
Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Kucuk, Murat; Soylak, Mustafa
The aim of the present study was to investigate the sorption potential of pine bark (Pinus brutia Ten.) for removal of Cr(VI) ions from aqueous solutions. The biosorption characteristics of Cr(VI) ions onto bark biomass were examined with respect to the changes in initial pH of the solution, contact time, initial Cr(VI) and bark concentration, bark particle size, temperature, etc. The biosorption isotherms were described by means of Langmuir and Freundlich models and the biosorption kinetics were analysed using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The thermodynamic parameters proved that the process was feasible, spontaneous and endothermic in nature.
- 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.
- MakaleYalnız künye2014Separation and preconcentration of lead, chromium and copper by using with the combination coprecipitation-flame atomic absorption spectrometric determination
Bahadır, Zekeriyya; Bulut, Volkan Numan; Ozdes, Duygu; Duran, Celal; Bektas, Hakan; Soylak, Mustafa
A coprecipitation method was developed for the quantitative separation and preconcentration of Pb(II), Cr(III) and Cu(II) ions. Analytes were coprecipitated using a triazole derivative (2-{4-[2-(1H-indol-3-yl)ethyl]-3-(4-chlorobenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl}. N-aryl methylidene acetohydrazid). The analytes were analyzed by flame atomic absorption spectrometry. The parameters such as sample pH, amount of reagent, sample volume, matrix effects etc. were investigated. The enrichment factor for the analyzed metal ions was obtained as 50. The relative standard deviations (RSD) were in the range of 2.8-4.1%. The accuracy of the proposed procedure was checked by the analysis of the CRM-C-Sandy Soil C. The method was successfully applied to real samples.