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Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/gumushane/19417
  Removal of Pb(II) ions from aqueous solutions by Brevibacillus agri-loaded clay: Kinetic, isotherm, and artificial neural network modeling

  Belduz, Ali Osman; Inan, Kadriye; Duran, Celal; Ozdes, Duygu; Ozeken, Sengul Tugba; Nalçaoğlu, Aleyna; Şeker, Serdal

  In this study, a novel and efficient adsorbent was developed by immobilizing inactivated Brevibacillus agri biomass onto an abundant natural clay via a simple synthesis route for Pb(II) removal from aqueous media. The adsorption behavior of inactivated Brevibacillus agri-loaded clay (BLC) was evaluated using batch experiments by investigating the effects of initial solution pH (2.0–6.0), BLC dosage (0.5–4.0 g/L), contact time (1–180 min), initial Pb(II) concentration (10–420 mg/L), temperature (25–80°C), and the presence of foreign ions. The optimum conditions were determined to be an initial solution pH of 5.0 and a contact time of 120 min. Isotherm models were applied to elucidate the interactions between Pb(II) ions and BLC, while kinetic studies were conducted to evaluate the adsorption performance and underlying mechanisms. The maximum adsorption capacity of BLC was determined as 65.4 mg/g according to the Langmuir isotherm model. Thermodynamic parameters revealed that Pb(II) adsorption on BLC was exothermic, feasible, and spontaneous at 25ºC. Artificial neural network (ANN) studies provided highly accurate predictions by modeling and confirmed the reliability and applicability of the model for Pb(II) removal in industrial applications. This study presents an innovative and sustainable approach for heavy metal removal, offering an effective solution applicable to environmental remediation processes.

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• MakaleAçık Erişim2026/r/gumushane/13917
  A novel cloud point extraction method using a benzimidazole-based ligand for the preconcentration of toxic heavy metals in water and food samples

  Ozdemir, Olcay; Duran, Celal; Mentese, Emre; Ozdes, Duygu

  In the present research, a novel cloud point extraction (CPE) method was developed for the separation and preconcentration of toxic Cu(ii), Ni(ii), Pb(ii), and Cd(ii) ions in environmental water and vegetable samples, prior to their determination by flame atomic absorption spectrometry (FAAS). The ligand 2-(2-(4-fluorobenzyl)-1H-benzo[d]imidazole-1-yl)acetohydrazide (FB-BIAH) was employed for the first time as an analytical complexing agent for the aforementioned metal ions, and Triton X-114 (TX-114) was preferred as the nonionic surfactant. Within the scope of optimizing CPE conditions, experimental parameters, such as pH, FB-BIAH and surfactant amounts, and incubation temperature and time, as well as centrifugation speed and duration, were systematically investigated. The optimal conditions for the simultaneous quantitative recovery of analyte ions were established as pH 7.0, an FB-BIAH amount of 2.5 mg, a TX-114 quantity of 25 mg, an incubation temperature of 60 °C, and an incubation time of 30 min. Under optimal conditions, the proposed method was successfully applied to river water and seawater, as well as different vegetable samples such as lettuce, parsley, and pepper. The results obtained demonstrated that the analyte ions could be reliably determined in complex matrices and that the method exhibited high analytical performance. Due to its simplicity, rapid applicability, environmentally friendly nature, and cost-effectiveness, the proposed CPE-FAAS method represents a promising approach for the routine analysis of toxic heavy metals in environmental water and food samples. This journal is

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• MakaleAçık Erişim2026/r/gumushane/13721
  Enhanced cationic dye adsorption using Stenotrophomonas indicatrix -modified MnFe2O4: performance evaluation and adsorption mechanism

  Ozdes, Duygu; Dede, Alper; Turfan, Fatma Asya; Seker, Serdal

  In this study, MnFe2O4 magnetic nanoparticles were modified with the Stenotrophomonas indicatrix bacteria for the first time in the literature to develop an effective and novel bio-adsorbent for the remediation of toxic cationic dyes, specifically Rhodamine 6G (R6G) and Methylene Blue (MB), from contaminated aqueous media. MnFe2O4 and bacteria-loaded MnFe2O4 were thoroughly characterized using FTIR, XRD, and SEM-EDX analyses. XRD results confirmed that the cubic spinel structure of MnFe2O4 was preserved after bacterial modification, while FTIR spectra evidenced the successful incorporation of biological functional groups, including –NH, –OH, amide, and phosphate moieties, onto the nanoparticle surface. Adsorption performance of the dyes was evaluated in terms of parameters including aqueous solution pH, equilibrium time, bacteria-loaded MnFe2O4 dosage, and initial R6G and MB concentration. After investigating the effect of salt on adsorption efficiency, the applicability of the proposed adsorbent was assessed using real water samples. According to the experimental results, the optimum pH and equilibrium period for the uptake of both dyes were determined to be 8.0 and 60 min, respectively. Kinetic analyses showed that the pseudo-second order kinetic model exhibited a superior fit in representing the adsorption rates of both dyes, while isotherm studies indicated that both Langmuir and Freundlich isotherm models fit the experimental data well. While the adsorption capacities of pure MnFe2O4 for MB and R6G were 19.5 mg g− 1 and 15.3 mg g− 1, respectively, these values reached 67.6 mg g− 1 and 59.5 mg g− 1 for the bacteria-loaded MnFe2O4. The obtained data revealed that bacterial modification significantly increased the adsorption capacity of MnFe2O4, suggesting that the developed bio-adsorbent stands out as an effective and promising candidate for the remediation of dye-contaminated effluents.

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• MakaleYayıncıda açık erişim2026/r/gumushane/13551
  Boric acid-activated carbon derived from Scots pine sawdust for phenol removal: adsorption mechanism, linear and nonlinear kinetic and isotherm modeling, and artificial neural network prediction

  Ozdes, Duygu; Turfan, Fatma Asya; Seker, Serdal; Kavgaci, Gonca; Onal, Yunus

  In this study, a sustainable activated carbon was successfully prepared from Scots pine sawdust via boric acid activation (H3BO3-AC-SPS) and evaluated for phenol adsorption from aqueous solutions. The physicochemical characteristics of the adsorbent were investigated using FTIR, SEM-EDX, XRD, and BET analyses, while the effects of solution pH, contact time, adsorbent dosage, initial phenol concentration, temperature, ionic strength, and reusability without regeneration on the adsorption performance were systematically examined. H3BO3-AC-SPS exhibited excellent adsorption performance over a wide pH range (5–8), showed good tolerance to coexisting inorganic ions and organic contaminants, and retained appreciable adsorption efficiency over five consecutive adsorption cycles without regeneration. Phenol uptake increased with temperature, and NaOH enabled partial desorption of phenol. The adsorption kinetics and equilibrium data were analyzed using both linear and nonlinear regression approaches and comparatively evaluated based on the coefficient of determination (R2), sum of squared errors (SSE), and root mean square error (RMSE). The pseudo-second order kinetic model and the Langmuir isotherm exhibited the best predictive performance, with the Langmuir model estimating a maximum adsorption capacity of 65.4 mg g−1. The adsorption mechanism may involve π–π interactions, hydrogen bonding, pore filling, and hydrophobic interactions. In addition, an artificial neural network (ANN) model accurately predicted the adsorption behavior, yielding a high correlation coefficient (R = 0.9789). The applicability of H3BO3-AC-SPS was further demonstrated in stream water and mining wastewater. These findings demonstrate that boric acid activation is an effective strategy for converting Scots pine sawdust into a high-performance adsorbent and that integrating linear and nonlinear adsorption modeling with statistical error analysis provides a reliable framework for interpreting adsorption behavior. This journal is

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• MakaleAçık Erişim2026/r/gumushane/12320
  Waste to resource approach: CoFe2O4-modified spent tea waste for magnetic solid-phase extraction of toxic metal ions from water samples

  Seker, Serdal; Ozdes, Duygu; Duran, Celal

  In this research, within the framework of a waste-to-resource conversion approach, biochar obtained from spent tea waste (STWB), a widely available and cost-free biomass source, was modified with magnetic CoFe2O4 nanoparticles to develop an environmentally friendly adsorbent (CoFe2O4/STWB). The applicability of this material for efficient separation and preconcentration of Cd(ii), Pb(ii), and Ni(ii) ions from mining wastewater, stream water, and wastewater samples collected from an organized industrial zone was systematically investigated using the solid phase extraction (SPE) method. Optimization of the experimental variables was conducted to enhance the extraction performance of the target analyte ions. The fact that the adsorption and desorption equilibrium times occur in less than 1 min demonstrates the rapid and highly efficient extraction performance of the developed adsorbent. Langmuir isotherm model analysis revealed that CoFe2O4/STWB exhibits adsorption capacities of 69.4 mg g−1 for Cd(ii), 185.2 mg g−1 for Pb(ii), and 45.2 mg g−1 for Ni(ii). In contrast, the corresponding adsorption capacities obtained for unmodified STWB were considerably lower, with values of 42.9, 75.8, and 16.8 mg g−1 for Cd(ii), Pb(ii), and Ni(ii), respectively. These results clearly demonstrate that modification with CoFe2O4 significantly enhances the adsorption performance of STWB. Consequently, CoFe2O4-modified spent tea waste can be regarded as an effective, economical, and sustainable adsorbent for trace heavy metal analysis in environmental water samples, owing to its rapid extraction kinetics, high adsorption capacity, and low detection limits. This journal is

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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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• MakaleAçık Erişim2025/r/gumushane/19722
  Removal of anionic and cationic dyes from aqueous solutions using drinking water treatment plant sludge (DWTS): Equilibrium and kinetic evaluation

  Duran, Celal; Ozdes, Duygu; Turfan, Fatma Asya; Kılıç, Neslihan; Yaltirik, Fatma

  The present research investigates the removal of Brilliant Green (BG) and Remazol Brilliant Blue R (RBBR) dyes by an adsorption system utilizing drinking water treatment sludge (DWTS) as an adsorbent. It aims to contribute to sustainable treatment methods by evaluating waste sludge as a low-cost and environmentally friendly adsorbent. In the study, the significant parameters affecting the adsorption process were systematically investigated. During the experiments, the effects of factors such as initial pH of the solution, equilibrium time, adsorbent amount and initial dye concentration on the adsorption efficiency were evaluated. The obtained data were tested with Langmuir and Freundlich isotherm models and it was determined that adsorption occurred on both homogeneous and heterogeneous surfaces. The maximum adsorption capacity of DWTS was calculated as 100.0 mg g-1 and 38.9 mg g-1 for BG and RBBR, respectively. Kinetic analyses were performed to understand the dynamics of the adsorption process. Pseudo-first order and Pseudo-second order kinetic models were evaluated and it was noticed that the pseudo-second order model explained the adsorption data better. As a result, DWTS has been proven to be an effective adsorbent in the removal of BG and RBBR. The findings indicated that DWTS has significant potential for evaluation in advanced treatment processes in terms of environmental sustainability.

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• MakaleYalnız künye2025/r/gumushane/14019
  Determination of selection-focused physicochemical properties in the local Eğrisap pear (Pyrus communis L.) clone grown in Rize

  Kalkisim, Ozgun; Aydin, Mehmet Zahit; Ozdes, Duygu; Duran, Celal

  Turkey, located within the Western Asia gene center, is a significant genetic center for many fruit species, including pears. Rize, a province in the Northeastern part of Turkey, is located within the Northeast Anatolia Region, which falls within the genetic center area where pears have undergone evolutionary development. This study aimed to identify promising local Eğrisap pear clone genotypes with superior traits and to introduce them into economic use. For this purpose, Rize province and its districts were surveyed, and fruit and leaf samples were collected from pre-selected Eğrisap pear clone types. These samples were subjected to pomological, morphological, and chemical analysis. The JMP 13 statistical software package was used to compare the Eğrisap pear clone types. According to the research results, the pomological and morphological traits of the clone types varied as follows: fruit weight (99.10–139.54 g), fruit width (54.52–65.41 mm), fruit length (57.58–68.83 mm), fruit stem length (50.75–59.50 mm), fruit stem thickness (2.36–2.91 mm), core width (5.15–7.55 mm), core length (9.73–14.51 mm), flesh firmness (3.61–7.13 lb), seed number (5.30–8.55), leaf width (45.80–60.04 mm), leaf length (64.53–82.37 mm), petiole length (37.04–60.99 mm), petiole thickness (0.83–1.20 mm), and soluble solid content (SSC) (9.10 %-16.0 %). Regarding chemical composition, the pH values of the clone types ranged from (3.78–4.22), titratable acidity (0.22 %-0.47 %), protein content (1.50 %-4.95 %), vitamin C content (0.92–2.28 mg/100 g), ash content (1.16 %-4.30 %), and total sugar content (9.66 %-17.28 %). Mineral element analysis of the local pear varieties revealed that iron content ranged from (0–14.7 µg/g), copper (2.90–9.12 µg/g), manganese (2.9–11.6 µg/g), magnesium (321.7–771.5 mg/g), zinc (0 µg/g), sodium (9.6–39.6 µg/g), potassium (5.43–14.50 µg/g), calcium (50.1–219.7 µg/g), cobalt (0.01–0.31 µg/g), cadmium (0–0.1 µg/g), and nickel (0.08–4.41 µg/g). Among the local Eğrisap pear clones grown in Rize, clone type 53 IYD 01 was identified as having the most superior quality criteria and chemical composition. Consequently, it is recommended that this clone type be introduced to producers for cultivation.

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• MakaleYayıncıda açık erişim2025/r/gumushane/13812
  Efficient extraction and determination of Au(iii) ions from acid mine drainage and water samples using silica gel immobilized with Brevibacillus borstelensis

  Camoglu, Aslihan Yilmaz; Duran, Celal; Ozdes, Duygu; Nalcaoglu, Aleyna; Bektas, Kadriye Inan; Belduz, Ali Osman

  The analysis of gold, which is a precious metal with limited resources, in environmental samples is crucial for the sustainable utilization of natural resources. Therefore, in the present research we have aimed to develop a novel and environmentally friendly bioadsorbent, Brevibacillus borstelensis loaded on silica gel (BB@Si), with outstanding adsorptive properties that can be implemented for quantitative recovery of Au(iii) ions via the solid phase extraction (SPE) technique. After characterizing the developed adsorbent using FTIR and SEM techniques, we conducted a detailed investigation of the critical parameters that influence the extraction performance of Au(iii) ions. Optimum parameters were observed as follows: pH 3.0, adsorption contact time 30 min, eluent type 0.1% (w/v) thiourea in 0.5 M HNO3, elution time 60 min, BB@Si amount 1.0 g L−1, and sample volume 400 mL. Some of the well-known isotherm and kinetic models were applied to the results observed from the adsorption studies. Equilibrium adsorption capacity of BB@Si was estimated to be 66.2 mg g−1 utilizing the Langmuir isotherm model while the limit of detection (LOD) and relative standard deviation (RSD%) were established as 0.99 μg L−1 and 3.7%, respectively. The developed method was utilized smoothly for the quantification of Au(iii) ions in mining wastewater, acid mine drainage (AMD), streams and seawater.

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