Yazar "Madenli, Ozgecan" seçeneğine göre listele

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    Characterization of littered face masks in the southeastern part of Turkey
    (Springer Heidelberg, 2021) Akarsu, Ceyhun; Madenli, Ozgecan; Deveci, Ece Ummu
    A possible source of microplastics has started to be released into nature because of the single-use face masks that protect us against the spread of COVID-19 and are being thrown onto the streets and into seas and nature. This study aims to estimate the amount of face mask use during the COVID-19 pandemic in Turkey, thereby expressing our concerns about waste management and plastic pollution and calling on appropriate solid waste management policies and governments to take the necessary measures to formulate their strategies at all levels. In this context, the number of masks in an area of 1 km(2) in 3 different cities was determined theoretically and experimentally. Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) were also used to evaluate plastic polymer characteristics of the single-use face mask. It was determined that the three cities produce roughly 10 tons of face masks in a day. With the increasing use of single-use plastics, the impact of face masks on microplastic pollution is of great concern. Although studies on the recovery of disposable masks continue, the level is insufficient. Therefore, studies to be carried out on technologies that will enable the repeated use of masks are important.
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    Effective removal of hexavalent chromium by novel modified alginate-based biocomposites: Characterization, kinetics and equilibrium studies
    (Elsevier Sci Ltd, 2023) Madenli, Ozgecan; Akarsu, Ceyhun; Deveci, Ece Ummu
    This study aims to synthesise novel biocomposites by combining fungal hyphae (Aspergillus oryzae or Penicillium roqueforti) and reduced graphene oxide to evaluate their adsorption potential for hexavalent chromium (Cr(VI)) from synthetic solutions and real wastewater. Fourier-transform infrared spectroscopy, scanning electron mi-croscopy, X-ray diffraction, and thermogravimetric analyses were used to characterize the effects of the carbon -based materials on microbial structure. In addition, independent variables including with a contact time (1-11 h), reduced graphene oxide concentration (0.1-1 g.L-1), and initial Cr(VI) concentration (10-50 mg L-1) were tested in batch-scale laboratory experiments by response surface methodology. Accordingly, maximum adsorp-tion was achieved at 11 h contact time, 1.0 g L-1 rGO, and 50 mg L-1 Cr(VI) with a removal rate of 98.9%. The pseudo-first-order and Freundlich isotherm models were well fitted. The results show that these biocomposites can serve as novel adsorbent for the removal of Cr(VI) from wastewater.
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    Phosphate recovery from digestate using magnesium-modified fungal biochar
    (Springer, 2024) Surmeli, Recep Onder; Madenli, Ozgecan; Bayrakdar, Alper; Deveci, Ece Ummu; Calli, Baris
    Mg-rich biochars have been used for the removal and recovery of phosphate (PO43-) and ammonium (NH4+) from waste streams. In this study, a novel magnesium-modified biochar (Mg-FBC) was synthesized by immobilizing waste magnesite dust (WMD) into Aspergillus niger fungal biomass for the adsorption of PO(4)(3- )and NH4+. Pyrolysis at various temperatures and analysis using techniques such as SEM-EDS, TGA, XRD, FTIR, and BET revealed that biochar produced at 650 degrees C (Mg-FBC650) exhibited enhanced surface properties favorable for effective adsorption. This improvement is attributed to the increased surface area facilitated by the hyphal structure of A. Niger and the effective dispersion of MgO on its surface. In experiments using a synthetic phosphate solution, the adsorption capacity reached 595 mg PO43-/g BC, fitting the Langmuir model at pH 9. In addition, experiments with the liquid fraction of a real digestate (LFD) showed adsorption capacities of 502 mg PO43-/g BC and 150 mg NH4+/g BC, respectively. The adsorption mechanism was elucidated through SEM-EDS, XRD, and FTIR analyses confirming that Mg-FBC650 facilitates a multifaceted adsorption mechanism, including adsorption, electrostatic attraction, chemical precipitation, and surface complexation. Consequently, PO43- was the primary adsorbate in the synthetic solution, while both PO43- and NH4+ were effectively removed from the LFD, indicating that Mg-FBC650 has substantial potential as an efficient adsorbent for nutrient removal. As a result, Mg-FBC650 is believed to hold significant potential as a slow-release and readily transferable bio-fertilizer, particularly suitable for application in soils deficient in organic matter, nitrogen, and phosphorus. [GRAPHICS] .
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    Synthesis of graphite/rGO-modified fungal hyphae for chromium (VI) bioremediation process
    (Taylor & Francis Ltd, 2024) Madenli, Ozgecan; Akarsu, Ceyhun; Adiguzel, Ali Osman; Altuntepe, Ali; Zan, Recep; Deveci, Ece Ummu
    Bioremediation is a promising technology that can eliminate the drawbacks of conventional treatment methods in removing harmful toxic metals including chromium(VI). Therefore, in this study, fungal hyphae modified with graphite and reduced graphene oxide were synthesized and assessed for their potential to bioremediate heavy metals for the first time in the literature. The effects of the carbon-based materials on microbial structure were characterized using scanning electron microscopy analysis. Thermogravimetric, RAMAN, X-ray diffraction, and enzymatic analyzes were performed to determine the role of functional groups. In addition, batch adsorption experiments utilizing response surface methodology were conducted to optimize operating parameters such as time (1-11 h), chromium (10-50 mg/L), and graphite/reduced graphene oxide (0.1-1 g/L). The maximum adsorption capacity with the graphene fungal hyphae was determined to be 568 mg.g(-1), which is 9.7 times that of the crude fungal hyphae. The Cr(VI) removal for fungal hyphae-graphite and fungal hyphae-reduced graphene oxide biocomposites was 98.25% and 98.49%, respectively. The isothermal and kinetic results perfectly matched the 2nd order pseudo-model and Langmuir model in terms of the nature of the adsorption process. The laboratory scale test results indicate that fungal hyphae modified with graphite and reduced graphene oxide have a high adsorption capacity, suitable for the removal of chromium (VI) from wastewater.
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    Synthesis, characterization, and phosphorus adsorption of Mg/Fe-modified biochar from cotton stalk pretreated with Coriolus versicolor
    (Wiley, 2024) Deveci, Ece Ummu; Oz, Derya; Madenli, Ozgecan
    In recent years, the research potential in utilizing biochars as adsorbents in adsorption processes has grown due to their eco-friendly and economical nature. However, biochar often possesses a negative surface charge that limits its affinity for binding anions. Nitric acid washing and pretreatment with Coriolus versicolor can break down the lignocellulosic structure in cotton stalk waste, facilitating the subsequent impregnation of Mg and Fe metal oxides. These pretreatment steps can lead to the production of diverse and functionalized biochars with higher adsorption capacities. In this study, cotton stalk waste was first washed with diluted nitric acid and then subjected to biological pretreatment by incubation with C. versicolor, followed by impregnation with Mg and Fe to obtain CV-CS/Fe and CV-CS/Mg biochars. The results showed that the applied pretreatments altered the physicochemical properties and significantly increased the phosphorus adsorption capacity. The adsorption capacities of CV-CS/Fe and CV-CS/Mg biochars were found to be 277.88 and 507.01 mg g(-1), respectively. The results indicate that the incorporation of multiple metal oxide impregnates enhances P adsorption. Furthermore, in the kinetic study, pseudo-first-order and pseudo-second-order models provided a well fit, determining chemical adsorption as the main adsorption mechanism for phosphorus adsorption. The biochars demonstrated compatibility with Langmuir-Freundlich models. Overall, the findings suggest the possibility of synthesizing biochars with improved adsorptive properties through pretreatment, and these engineered biochars hold promising potential as effective adsorbents in the field.
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    Treatment of slaughterhouse wastewater by electrocoagulation and electroflotation as a combined process: process optimization through response surface methodology
    (Springer Heidelberg, 2021) Akarsu, Ceyhun; Deveci, Ece Ummu; Gonen, Cagdas; Madenli, Ozgecan
    The contamination of water with organic compounds has become an increasing concern in today's world. The cost-effective and sustainable treatment of industrial wastewaters is a major challenge. Advanced treatment techniques such as electrocoagulation-electroflotation offer economic and reliable solutions for the treatment of industrial wastewater. In this study, the electrocoagulation-electroflotation method was investigated for the simultaneous removal of chemical oxygen demand, total phosphorus, total Kjeldahl nitrogen, and color via response surface methodology. Factors such as electrode combination (Fe and Al), current density (10-20 mA/cm(2)), pH (3.0-9.0), and electrode distance (1-3 cm) were investigated in the treatment of wastewater to obtain maximum treatment efficiency. It was determined that chemical oxygen demand, total Kjeldahl nitrogen, total phosphorus, and color removal reached up to 94.0%, 77.5%, 97.0%, and 99.0%, respectively. Treatment costs were found as $0.71 with the Al-Fe electrode combination.