Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2023Scopus SJRQ3/r/gumushane/12645
  Comparison of the removal efficiencies of Basic red 46 from aqueous solutiousing Aşkale lignite with and without ultrasound assisted processes

  Karaca, Canan; Karaca, Melike; Kıranşan, Murat; Karaca, Semra; Açışlı, Özkan; Gürses, Ahmet

  This study compared the removal efficiencies of Basic red 46 from aqueous solutions with and without ultrasound-assisted processes using lignite as a low-cost adsorbent. The effects of various experimental parameters such as contact time, adsorbent dosage, initial solution, pH, initial dye concentration and temperature on the dye removal efficiency were investigated. The experimental results were modelled by the kinetic and isotherm models. Both of processes fitted well to pseudo-second-order kinetics and the Langmuir model with highest correlation coefficients for all of three temperatures. The results showed that the influence parameters have a different effect on the removal efficiency in the presence and absence of ultrasonic irradiation. When the results obtained for both processes are compared, it is seen that the removal efficiency obtained with the ultrasound assisted process is much higher than that obtained with non-ultrasound assisted process at high dye concentrations. The removal efficiency of ultrasound-assisted and unassisted processes was found to be 81.5% and 54.6%, respectively, at 80 mg/L dye concentration and 60 min. Thermodynamic parameters showed that the adsorption process was spontaneous and exothermic. The enthalpy and entropy changes for the ultrasound-assisted process were –9.35 kJ/mol and –0.03 kJ/K·mol, respectively.

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  AtıfScopus6·WoS5·OpenAlex9

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• MakaleAçık Erişim2021Scopus SJRQ3/r/gumushane/14956
  Investigation of the removal of sulfamethoxazole drug waste from aqueous solutions under the effect of zinc oxide/montmorillonite nanocomposite by photocatalytic ozonation process

  Özyürek, Işıl Nihan; Kıranşan, Murat; Karaca, Semra

  In this study, the synergistic effect of photocatalysis and ozonation processes to degrade the sulfamethoxazole (SMX), one antibiotic pharmaceutical compound, has been studied through the influence of main operational variables such as zinc oxide/montmorillonite (ZnO/MMT) dos-age, SMX initial concentration, ozone flow rate, pH and the addition of organic and inorganic scavengers. Synthesized ZnO nanoparticles were immobilized on the montmorillonite surface to prepare ZnO/MMT catalyst as a photocatalyst. The catalyst was characterized by X-ray fluo-rescence, X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscope and N2 adsorption/desorption. The highest SMX degradation efficiency (80.84% for 30 min of reaction time) was obtained for the photocatalytic ozonation process compared to adsorption, single ozonation, catalytic ozonation, and photolysis. ZnO/MMT was more effective photocatalyst according to ZnO, indicating its usability as a promising photocatalyst for the removal of organic contaminants in aqueous solutions. The reduced degradation efficiency with the addition of organic and inorganic scavengers showed the important role of the photo-produced radicals and holes as well as direct ozonation in SMX degradation. A mechanism is also proposed for photocatalytic ozonation degradation by using the gas chromatography-mass spectroscopy (GC-MS) analysis method. Finally, several by-products were identified by GC-MS analysis, which allowed to depict a possible mechanism for the sulfamethoxazole degradation.

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  AtıfScopus9·WoS7·OpenAlex10

  İncele
• MakaleAçık Erişim2021Scopus SJRQ3/r/gumushane/14621
  Satellite-derived shallow wetland bathymetry using different classification algorithms and datasets

  Dervisoglu, Adalet; Yagmur, Nur; Bilgilioglu, Burhan Baha

  Remote sensing (RS) effectively identifies, analyzes, and monitors wetlands. In addition to these two-dimensional studies, RS is used with several techniques in determining shallow water depths. The primary purpose of this study is to obtain shallow wetland bathymetry utilizing spectral reflections obtained at different water depths by field study and satellite images. Machine learning (ML) algorithms, which are widely used in remote sensing, are used in this study. Four algorithms were selected as random forest (RF), support vector machine (SVM), Neural Networks (NN), and Maximum Likelihood Classification (MLC). Since machine learning algorithms use training samples/datasets, the classification accuracy is directly related to selecting these data. The effect of pixel counts on classification was investigated by using two different training data set also. Duden (Kulu) Lake, which is a shallow wetland, was chosen as the study area. The Iterative Self-Organizing Data Analysis Technique (ISODATA) classification algorithm divided into as many clusters as possible was applied on Sentinel-2 multispectral images. All classes were rede-fined using measured spectral signatures and were created a bathymetric map. This map was used as reference data in creating training sets and the accuracy assessment of ML algorithms. When the water surface areas obtained from algorithms were compared with the bathymetric map and Normalized Difference Water Index, the best result was obtained with RF. According to the accuracy assessment results, it was seen that the number of training data affects the accuracy, and the best results were obtained with SVM and RF algorithms with training data containing more pixels (overall accuracy 93.87% and 92.64, kappa 0.89 and 0.87, respectively).

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  AtıfScopus1·WoS1·OpenAlex1

  İncele
• MakaleAçık Erişim2021Scopus SJRQ3/r/gumushane/11309
  Experimental and numerical studies on predicting and improving the full-scale wastewater treatment plant hydrodynamics

  Şibil, Rahim; Aras, Egemen; Kankal, Murat

  This paper presents the results of both experimental and numerical studies on biological wastewater treatment plant (WWTP), oxidation ditches (OD) hydrodynamics to design and develop the desired flow conditions of the WWTP. Computational fluid dynamics (CFD) models were developed using CFD software, ANSYS Fluent (V13) with the three-dimensional, steady, incompressible flow based on the Reynolds-Averaged Navier-Stokes equations for flow field calculations in the combined ODs. Also, three different turbulence models [standard k–ε (ske), renormalization group k–ε (RNG), and realizable k–ε (real)] were performed for a comparative study. The numerical model was verified based on the experimental data in the relative errors for ske, RNG, and real 13%, 17%, and 18%, respec-tively. According to the parametric studies, the hydrodynamic characteristics of the existing WWTP were investigated. The maximum wastewater velocity occurred at the inlet and outlet, affecting the flow field in ODs. Moreover, the water velocity decreased as it moved away from the inlet and outlet locations at vertical and horizontal. It can also be noted that there was no homogeneous flow field distribution in ODs. Because the current OD model needs improvement hydrodynamically, a new original OD geometry was presented to eliminate the hydraulic weakness of existing WWTP by CFD analysis. The new original geometry provides a more homogeneous flow field in ODs that mean it will also help treatment efficiency and energy saving according to the operating principles of this facility.

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  AtıfScopus8·WoS8·OpenAlex8

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• MakaleAçık Erişim2015Scopus SJRQ2/r/gumushane/12043
  Simultaneous 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.

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  AtıfScopus17·WoS16·OpenAlex16

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• MakaleAçık Erişim2014Scopus SJRQ2/r/gumushane/15796
  Assessment 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.

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  AtıfScopus19·WoS20·OpenAlex19

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• MakaleAçık Erişim2014Scopus SJRQ2/r/gumushane/13204
  Kinetics, 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.

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  AtıfScopus45·WoS39·OpenAlex51

  İncele
• MakaleAçık Erişim2012Scopus SJRQ2/r/gumushane/15648
  Dehydrated hazelnut husk carbon: A novel sorbent for removal of Ni(II) ions from aqueous solution

  Sivrikaya, Sezen; Albayrak, Sinem; Imamoglu, Mustafa; Gundogdu, Ali; Duran, Celal; Yildiz, Hulya

  The present study has been performed to examine the adsorption ability of novel sorbent dehydrated hazelnut husk carbon (DHHC) towards Ni(II) ions from aqueous solution using the batch adsorption technique. The effective factors such as initial pH of the aqueous solution, contact time, initial Ni(II) concentration, adsorbent dosage, and temperature were investigated. The studies were also conducted to understand the effect of some co-existing ions which may be present in aqueous solutions. DHHC showed good adsorption potential for Ni(II) ions. The optimum initial pH value was selected as 5.0. The experimental data fitted well to the Langmuir adsorption isotherm model. Among the kinetic models tested for the adsorption of Ni(II), the pseudo-second-order model showed a good fit of the kinetic data. The thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the adsorption of Ni(II) ions onto DHHC was feasible, spontaneous, and exothermic in the temperature range of 25-55°C. The results of this study showed the effectiveness and feasibility of DHHC for the removal of Ni(II) ions from aqueous solution.

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  AtıfScopus33·WoS33·OpenAlex33

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