Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2026/r/gumushane/12246
  Valorization of tea industry waste into boric acid–activated carbon for phenol removal from aqueous solutions

  Duran, Celal; Ozdes, Duygu; Ozdemir, Olcay; Onal, Yunus; Gundogdu, Ali

  The tea industry generates substantial quantities of solid waste with limited high-value industrial applications. In this study, tea industry waste was converted into boric acid-activated carbon (BA–TAC) through a simple one-step chemical activation process and evaluated as an adsorbent for phenol removal from aqueous solutions. BA–TAC exhibited a mixed micro–mesoporous structure with a BET surface area of 592.59 m2 g−1. The adsorption performance was investigated as a function of solution pH, contact time, and initial phenol concentration. Adsorption kinetics were evaluated using pseudo-first order, pseudo-second order, Elovich, Avrami, and intraparticle diffusion models, whereas equilibrium data were analyzed using Langmuir, Freundlich, and Sips isotherms. Linear, pseudo-linear, and non-linear regression approaches were comparatively evaluated, demonstrating the limitations of conventional linearization and the superiority of direct non-linear regression. Moreover, the so-called linearized forms of multi-parameter models such as Sips are not truly linear because iterative parameter estimation remains necessary. The maximum experimental phenol adsorption capacity reached 101.80 mg g−1 despite the moderate BET surface area of BA–TAC. The experimentally determined natural pH and pHpzc values, together with the limited desorption efficiency, indicated that adsorption was governed predominantly by surface chemical interactions rather than electrostatic attraction alone. XPS analysis confirmed the incorporation of boron-containing surface functionalities, highlighting their contribution to phenol adsorption. Overall, this study demonstrates the successful valorization of tea industry waste into a functional boron-modified activated carbon while providing methodological guidance for reliable adsorption kinetics and equilibrium modeling, thereby supporting sustainable waste valorization.

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• MakaleAçık Erişim2026/r/gumushane/12228
  Selective Determination of Trace Co(II) and Cu(II) in Food and Environmental Matrices via Carrier Element-Free Coprecipitation Using a Novel Thiosemicarbazone-Derived Schiff Base

  Bulut, Volkan N.; Demirci, Hamit; Ozdes, Duygu; Gundogdu, Ali; Bektas, Hakan; Soylak, Mustafa; Duran, Celal

  A carrier element-free coprecipitation (CEFC) method was developed for the preconcentration and determination of trace Co(II) and Cu(II) in environmental and food samples using a novel thiosemicarbazone-derived Schiff base ligand (MBITAH). Unlike conventional coprecipitation approaches, the proposed strategy eliminates the need for inorganic carriers, reducing potential interferences and improving selectivity toward the target analytes. Under optimized conditions (pH 7.0, 1.5 mg ligand), quantitative recoveries were achieved with limits of detection of 1.16 and 0.79 µg L⁻1 for Co(II) and Cu(II), respectively. A preconcentration factor of 50 enabled sensitive determination by flame atomic absorption spectrometry (FAAS) with good precision (RSD ≤ 3.7%). The method exhibited good tolerance toward common matrix ions and was validated using certified-reference material (CRM-SA-C Sandy Soil C) and spike/recovery tests, showing agreement with certified values (p > 0.05). Its applicability was demonstrated in sea water, stream water, and food samples (red lentil and bulgur), confirming reliable performance in complex matrices. Compared with previously reported approaches, the proposed CEFC method offers a favorable balance between analytical performance, simplicity, and cost-effectiveness. In addition, greenness assessment using the AGREE tool yielded a score of 0.45, indicating a moderate-to-good level of environmental friendliness.

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• MakaleYalnız künye2023/r/gumushane/10252
  Characterization 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.

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• MakaleAçık Erişim2020/r/gumushane/17823
  İçme 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.

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• MakaleYalnız künye2020/r/gumushane/12920
  Effect of antimonite mineralization area on heavy metal contents and geochemical fractions of agricultural soils in Gümüşhane Province, Turkey

  Sungur, Ali; Vural, Alaaddin; Gundogdu, Ali; Soylak, Mustafa

  In this study, the possible impacts of an antimonite mineralization area on agricultural lands with regard to heavy metal concentrations were examined. In this scope, surface soil samples (0–20 cm) were taken from a total of 27 locations including eleven from the Avliyana antimonite mineralization area (Torul, Gümüşhane-NW Turkey) and its surroundings, eleven from agricultural areas and five from the control area. Wet digestion method was used with aqua regia procedure for determining the total heavy metal (Cd, Cr, Cu, Ni, Pb, Zn) concentrations of the soil samples. The geochemical fractions of heavy metals in soil samples were determined by way of a sequential extraction procedure. The total heavy metal contents of the soils were determined as: Ni > Cr > Zn > Cu > Pb > Cd for control soils, Cr > Ni > Zn > Cu > Pb > Cd for agricultural soils and Zn > Cu > Ni > Cr > Pb > Cd for mining area soils. It was determined that especially the values of Zn (57.6 ± 6.2 μg/g) and Cu (52.4 ± 5.8 μg/g) were high at the mineralization area due to hydrothermal alterations that are effective in the formation of mineralization. It was put forth as a result of sequential extraction that the heavy metals examined excluding Pb were observed dominantly in the residual fraction for all data set. On the other hand, it was determined that the non-residual mobile fractions reached from 11% Cr to 78% Pb in control soils, from 20% Cd to 88% Pb in agricultural soils and from 24% Cd to 87% Pb in mineralization area soils. Contamination signals due to mineralization area were monitored by way of the metal content in mobile fractions. Even though the metal concentrations determined in short term are not alarming for agricultural production, signals were observed especially for Cd, Pb, Cu, Ni and Zn elements to be more mobile in mineralization area soils in the long term due to the impact of environmental factors thereby being carried over to and accumulating in agricultural soils. In conclusion, while it is expected that the metal inputs due to mineralization areas may increase in the future, it is suggested to include plant analyses in future studies for determining the impact of the amount of bioavailable metal.

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• MakaleYalnız künye2018/r/gumushane/15277
  Adsorption 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.

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• MakaleYalnız künye2018/r/gumushane/15195
  Quality properties of wheat breads incorporated with dried sourdoughs produced with different fermentation and drying methods

  Hendek Ertop, M.; Ilter, S.M.; YilMaz, F.; BaltaCi, C.; Gündogdu, A.

  The aim of this study was to evaluate the effect of the dried sourdoughs produced with two different fermentation methods [Spontaneous fermentation(SPF) and starter of lactic acid bacteria-added fermentation(STF)], and three different drying methods (Drying in oven;DO, Freeze drier;DFD, and Spray drier;DSD) on various quality properties of the wheat bread. The bread samples prepared by addition of the dried sourdoughs at the rates of 3 %, 6 % and 12 %, and control bread prepared without sourdough were compared in terms of bioactivity, shelf life, physicochemical and sensory properties. The addition of the dried sourdough affected the specifc volume, pH and acidity of the bread samples signifcantly (p < 0.05), and a slow down moisture loss occurred during shelf life.The a*value of crust, antioxidant activity, and sensory properties were improved compared to the control bread. The use of dried sourdough at the rate of 12 % gave the most effective results. When the fermentation and drying methods were evaluated together, the combinations of SPF/DO, SPF/DFD and STE/DSD gave the best results.

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• MakaleYalnız künye2018/r/gumushane/15161
  Modeling 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.

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• MakaleAçık Erişim2018/r/gumushane/13367
  A nutritional evaluation of the berry of a new grape: 'Karaerik' (Vitis vinifera L.)

  Kurt, Aynur; Colak, Nesrin; Bengu, Aydin Sükrü; Gundoğdu, Ali; Akpinar, Erdal; Hayirlioglu-Ayaz, Sema; Ayaz, Faik Ahmet

  Grape berries are a good source of nutrients and nutraceuticals and have many benefits for human health. Growing interest in the export potential and consumption of a new grape (cv. Karaerik), cultivated as a table grape in Turkey, encouraged us to profile its major nutrient contents from six different locations. Due to its popularity, the nutritional value of this grape berry needs to be investigated to ascertain its potential economic and health benefits. The most abundant sugars in the grape berry were fructose and glucose (peel/whole fruit; averages 236.57 and 127.87, and 183.36 and 108.60 g kg -1 fresh weight, respectively), while the major organic acids were tartaric and malic acids (7.17 and 2.81, and 2.61 and 1.76 g kg -1 fresh weight, respectively). Linoleic acid (peel/whole fruit/seed; 37.14, 33.12 and 57.83%, respectively) was the predominant fatty acid, while potassium (peel/whole fruit/seed; 9331.5, 10226.33 and 5354 μg/g dry weight, respectively) was the predominant mineral, followed by phosphorus (1592.8, 2672 and 3072.67) in the berry. Our results demonstrate that the nutrient components and physicochemical parameters varied significantly among the sampling locations. The grape berry contains considerable quantities of potentially beneficial healthy nutrients worthy of further evaluation.

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• MakaleYalnız künye2017/r/gumushane/13392
  Environmental impact of Gümüşhane City, Turkey, waste area in terms of heavy metal pollution

  Vural, Alaaddin; Gundogdu, Ali; Akpinar, Ibrahim; Baltaci, Cemalettin

  The aim of this study is to investigate the occurrence of a heavy metal contamination in a solid waste site of Gümüşhane City, Turkey, to examine the dimensions of the risk of contamination, and to present suggestions for possible solutions. For this purpose, heavy metal contents of soil and leachate samples taken from a Gümüşhane waste site were determined by a new method, microwave plasma-atomic emission spectrometry (MP-AES). When the obtained results are compared with background and control values, it can be seen that the region carries contamination risks, especially in terms of heavy metals such as Zn, Cd, Pb, Cu, Ni, and Co. To examine the environmental effects of the landfill area in more detail, geodeposition index (Igeo), enrichment factor (EF), contamination index (PI), and combined contamination index (IPI) parameters are used. In addition, the samples taken from an area supposed to be free of pollution risk were also analyzed as control samples, and the obtained data were statistically compared with the results of the waste area. It is determined that the results of landfill waste site are dissimilar to those of comparison samples in terms of investigated metals, and that they contained higher values in general.

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