Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
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Review Citation - Scopus: 5A Comparative Evaluation of Dark Fermentative Bioreactor Configurations for Enhanced Hydrogen Production(Springer, 2025) Gören, Ayşegül Yağmur; Dincer, I.; Khalvati, A.Energy from renewable resources has been growing in popularity, which ultimately helps reduce emissions of greenhouse gases (GHGs) and contaminants. Since hydrogen (H2) has a higher combustion production of energy than hydrocarbon fuels, it has been identified as a clean, sustainable, and environmentally friendly energy source. There are several benefits to producing biohydrogen (bioH2) from renewable sources, including lower cost and increased sustainability. Among the bioH2 production processes, dark fermentation supports commercialization and scale-up for industrial applications. This paper considers the various bioreactors, such as anaerobic sequencing batch, continuous stirred, up-flow, fixed-bed, and membrane reactors, and their operational approaches for bioH2 production. This review paper also performs the bibliometric analysis method to identify historical and current developments in a particular field of reactor configuration studies. Furthermore, the main variables influencing reactor performance and methods for increasing process efficiency considering economic and environmental aspects are addressed. The results revealed that continuously stirred reactors are widely utilized for bioH2 production as a cost-effective reactor configuration. Moreover, the membrane bioreactors and fixed-bed reactors are yielded higher bioH2 performance than other configurations. Nevertheless, high energy consumption and costs have presented the need for further development of reactors. Consequently, future recommendations to solve the critical problems faced in reactor configurations, the gaps in the literature, and the points that need improvement were comprehensively reported. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.Article Assessment of Heavy Metal Contamination and Removal Using <i>ceratophyllum Demersum</I> L.: a Case Study(inderscience Enterprises Ltd, 2024) Karaoglu, Aybike Gul; Gören, Ayşegül Yağmur; Kobya, Mehmet; Goren, Aysegul Yagmur; Mese, Esra; Tepe, MelikeAssessment of heavy metal contamination in aquatic ecosystems continues to remain challenging. In this regard, Ceratophyllum demersum L. (C. demersum L.) is a common species found in rivers and can be used as a bioindicator to see the accumulation of heavy metals in the plant body. In this study, we aimed to investigate the accumulation of toxic metals and their effects on photosynthetic pigment content in plants for different seasons. The highest metal accumulations were observed in October 2019. The mean boron concentrations were 399 mg/kg in October 2019, while they were measured as 163 mg/kg in July 2020, most probably due to the decreasing agricultural activities in the studied area. However, the highest metal concentrations (aluminium 3,941 mg/kg and iron 5,161 mg/kg) were measured in July 2010. Moreover, the pigment content values were decreased with the increasing metal concentration in plants. The highest pigment content of 4.7 mu g/g was observed in October 2019, related to the low metal contamination in this season. Overall, C. demersum L. is a promising bioindicator of heavy metal pollution in water bodies with a significant amount of heavy metal accumulation capacity in a sustainable manner.Review Citation - WoS: 16Citation - Scopus: 17Green Biohydrogen Production From Renewable Plant-Based Resources: a Comparative Evaluation(Institution of Chemical Engineers, 2024) Goren,A.Y.; Gören, Ayşegül Yağmur; Dincer,I.; Khalvati,A.Increasing energy demand drives the need for environmentally sustainable and economically viable renewable resources to eliminate problems related to greenhouse gas emissions. In recent years, research on biohydrogen (bio-H2) production as a renewable energy source has been recognized as a potential subject. It aims to reduce the pressures set by carbon dioxide emissions and the depletion of fossil fuel supplies. The field of bio-H2 science is considered potentially important; there have been increasing efforts to develop feasible systems for viable applications. This review further presents an updated and comprehensive review of bio-H2 production by dark fermentation (DF), photofermentation (PF), microbial electrolysis cells (MEC), and hybrid processes using plant-based materials. Among these processes, the highest H2 production yield of 680.8 mLH2/g-biomass was obtained using the DF-PF hybrid process. A comparison of bio-H2 production yields, the environmental impact, and the costs of DF, PF, MEC, and hybrid systems is considered, and superior performance was obtained for integrated biological processes. The comparative evaluation results showed that the MEC process is the most economical technology, followed by integrated systems. The PF is the most environmentally friendly H2 production process, presenting the lowest global warming potential (GWP) value of 1.88 kgCO2eq./kgH2 and acidification potential (AP) of 3,61 gSO2/kgH2 ; it is followed by DF and MEC processes. On the other hand, the highest GWP of 14.8 kgCO2eq./kgH2 and AP 103 gSO2/kg H2 were obtained for the DF-MEC process related to electrical and heat requirements during the production process. Furthermore, the WCP and WSF values were 84.5 and 3632.9 m3 for the DF-MEC integrated process due to the water utilization in anode and cathode solutions, while WCP was 2.91 m3 for the DF process. Overall, the results of this study further revealed that substantial effort, in the current and future, should be performed on bio-H2 production from plant-based biomass using integrated biological processes. Moreover, the bibliometric analysis presented that bio-H2 production from plant-based materials, MEC systems utilization, and nano-additives are growing areas in the bio-H2 research that provide zero-carbon energy in the future. © 2024 The Institution of Chemical EngineersReview Citation - WoS: 60Citation - Scopus: 66A Comprehensive Review on Environmental and Economic Impacts of Hydrogen Production From Traditional and Cleaner Resources(Elsevier Sci Ltd, 2023) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, Ali; Gören, Ayşegül Yağmur; Dinçer, İbrahimThis review paper considered the potential hydrogen (H2) production methods using conventional fossil fuels and in a cleaner manner with biomass and water resources and evaluated them for economic sustainability, environmental impact, and energy efficiency. The study results revealed that the methods of biomass-based hydrogen production (e.g., photo-fermentation (PF), dark fermentation (DF), and microbial electrolysis cell (MEC)), by energy source, appear to more environmentally friendly than the other evaluated methods in terms of emissions since they offer the potential to significantly reduce CO2 releases when their substrates are derived from renewable resources or wastes. Among the biomass-based processes, the PF is the most environmentally friendly H2 production process, presenting a low global warming potential (GWP) value of 1.88 kgCO2 eq./kgH2 and acidification potential (AP) of 0.003 gSO2/kgH2, it is followed by DF and MEC processes. On the other hand, the highest GWP of 19.85 kgCO2 eq./kgH2 and AP 0.139 kgSO2/kg H2 were obtained for the fossil fuel-based gasification process related to coal mining and transportation operations. Although hydrogen production processes seem to consume high amounts of water sources, such as about 9 kg of water consumed for 1 kg of hydrogen produced during conventional electrolysis, the reality is that in the hydrogen ecosystem the water footprint of the process is reduced drastically where hydrogen is employed as fuel in fuel cell systems and converted back to water while generating electricity. So, the hydrogen ecosystem may diligently be recognized as the water conserving cycle. On the other hand, the study results showed that commercially available fossil fuel based (e.g., coal) gasification and steam-methane reforming processes are more advantageous over other lab scale technologies in terms of cost and process efficiency. Nevertheless, rising carbon costs may reduce the reasonable price of fossil-based H2 and promote the cost-competitiveness of biomass-based renewable H2. Overall ranking results also proved that biomass-based H2 production processes are primarily promising options for H2 production in an environmentally friendly and moderately cost-effective way.Review Citation - WoS: 22Citation - Scopus: 30Comparative Environmental Sustainability Assessment of Biohydrogen Production Methods(Elsevier, 2023) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, Ali; Gören, Ayşegül Yağmur; Dinçer, İbrahimAs energy crisis is recognized as an increasingly serious concern, the topic on biohydrogen (bioH(2)) production, which is renewable and eco-friendly, appears to be a highly-demanding subject. Although bioH(2) production technologies are still at the developmental stage, there are many reported works available on lab- and pilot-scale systems with a promising future. This paper presents various potential methods of bioH(2) production using biomass resources and comparatively assesses them for environmental impacts with a special emphasis on the specific biological processes. The environmental impact factors are then normalized with the feature scaling and normalization methods to evaluate the environmental sustainability dimensions of each bioH(2) production method. The results reveals that the photofermentation (PF) process is more environmentally sustainable than the other investigated biological and thermochemical processes, in terms of emissions, water-fossil-mineral uses, and health issues. The global warming potential (GWP) and acidification potential (AP) for the PF process are then found to be 1.88 kg-CO2 eq. and 3.61 g-SO2 eq., which become the lowest among all processes, including renewable energy-based H-2 production processes. However, the dark fermentation-microbial electrolysis cell (DF-MEC) hybrid process is considered the most environmentally harmful technique, with the highest GWP value of 14.6 kg-CO2 eq. due to their superior electricity and heat requirements. The water conception potential (WCP) of 84.5 m(3) and water scarcity footprint (WSF) of 3632.9 m(3) for the DF-MEC process is also the highest compared to all other processes due to the huge amount of wastewater formation potential of the system. Finally, the overall rankings confirm that biological processes are primarily promising candidates to produce bioH(2) from an environmentally friendly point of view.Book Part Arsenic Removal by Electrocoagulation(Wiley, 2022) Gören, Ayşegül Yağmur; Kobya, MehmetBecause of the toxic impacts on human health, the arsenic (As) limit value in drinking water was decreased from 50 to 10 ?g l-1 by the relevant authorities (WHO 1993; US EPA 2001). In this case, the problem of As pollution in natural water resources used for drinking water has grown even more and turned into a global crisis. According to reports in many parts of the world, over about 230 million people appear to be affected by high arsenic concentrations in groundwater. In this case, it turned out that there was a great need for cost-effective and environmentally friendly technologies from drinking water sources. One of the emerging water treatment technologies in recent years is electrocoagulation (EC) and it has been seen that it is effective in treating As (>99%) from water and eliminates some of the disadvantages of other conventional treatment processes. EC method includes electro-oxidation of anode electrode materials (iron and aluminum) and in situ production of coagulant agents. From groundwater resources with As content of 5-1000 ?g l-1, As removal efficiencies and operating costs (OCS) of EC technology using iron (Fe) and aluminum (Al) anodes were 85.0-99.9% and 0.0020-1.04 US$ m-3, respectively. Different types (plate, scrap, rod, and ball) of electrodes were used for As removal with the EC process, and it was observed that Fe electrodes or Fe-Al hybrid electrodes performed better in As removal. In addition, it has been determined that arsenate (As(V)) removal is more effective than arsenite (As(III)). A significant quantity of As(III) is oxidized in the EC process, resulting in precipitation, adsorption, and metal-oxy hydroxylic complex reactions. EC process has a lower OC to achieve As removal below the permissible WHO value compared to conventional treatment processes, accomplishing it as a further applicable option for As removal. © 2023 John Wiley & Sons, Inc.Article Citation - WoS: 17Citation - Scopus: 20Polyoxometalate-Based Hybrid Composites in Multi-Functional Wastewater Treatment Applications(Elsevier, 2023) Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur; Orooji, Yasin; Vatanpour, Vahid; Kudaibergenov, Nurbolat; Khataee, AlirezaThe inorganic polyanionic clusters known as polyoxometalates (POMs) have several structural variations at the nanoscale scale. They have many uses in chemistry, materials science, medicine, and other fields. This review considers the developments in treating hazardous contaminants from wastewater using POMs-based compounds. Four main treatment methods using POM-based compounds to remove water pollutants have been developed: adsorption, photocatalytic treatment, Fenton-like treatment, and membrane separation. Moreover, we report the types of POMs, synthesis procedures, strategies performed to modify POM-based compounds, and their appli-cations in wastewater treatment. To promote the development of these compounds for large-scale production and real-scale applications, gaps in knowledge and recent research obstacles are also pointed out. Most research on metal organic complexes (MOCs) based on POM has focused on using these compounds as catalysts, with little focus on their additional uses. The adsorption and photocatalytic efficiency of modified POM-based compounds are attributed to their enhanced contaminant removal efficiency, and recovery of certain POM-based compounds by magnetic separation is presented as a promising option for their recyclability. Among the reviewed studies, the highest adsorption capacity was 1108.9 mg/g, with a removal efficiency of 100 % for acid red dye using poly-[N,N-dimethyl-dodecyl-(4-vinylbenzyl)ammonium chloride] (PIL)-POM. The studies also indicate that the POM-based adsorbents could be effectively reused to remove pollutants and sustain their activity in 3-10 cycles. This review is believed to provide an overview of recent advancements in POM-based compounds for water and wastewater treatment, offers thorough research to anyone interested in learning more about this topic, and acts as a manual for researchers working in this area.Article Citation - WoS: 7Citation - Scopus: 7Insights Into Sustainability of Engineered Carbonaceous Material-Based Technologies for Advanced Cyanide Removal From Wastewater(Elsevier, 2023) Yoon, Yeojoon; Khataee, Alireza; Gören, Ayşegül Yağmur; Recepoğlu, Yaşar KemalCyanide (CN) is a serious concern in industrial and goldmine wastewater. Strict regula-tory standards have been established by various agencies due to the detrimental effects that CN has on human health. Therefore, before discharge to water bodies or land, it is essential to create a sus-tainable model for the safe removal of CN. Carbon-based materials are well known for their adsorption and oxidation features, which can be conducive to CN removal. This paper reviews the relevant literature on the application of modified and unmodified carbon-based materials to CN removal in water; these materials include activated carbon (AC), graphene, graphene oxide (GO), and carbon nanotubes (CNTs). Moreover, CN removal mechanisms and photocatalytic removal of CN are comprehensively discussed, with a particular emphasis on modifying carbon-based materials. It has been observed that adding various elements to carbon-based materials improves their surface area, functional groups, CN adsorption capacity, and pore volume. Impacts of operational parameters, isotherm models, kinetics, and types of carbon-based materials are also outlined. This study provides insight into the real-scale applicability of carbon-based materials for CN removal from waters. Moreover, this review indicates that essential work on CN removal using carbon-based materials is still needed. Future research should focus on developing modified carbon-based materials to encourage multidisciplinary research. The most crucial gap in the literature is that the studies have been performed on a lab scale. Therefore, further pilot and real-scale applica-tions should be conducted. Overall, the cost assessment, environmental effects, and human health risks of carbon-based materials should be studied in future research to achieve a realistic perspective on applicability on an industrial scale.(c) 2023 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).Article Citation - WoS: 12Citation - Scopus: 14Identifying Geogenic and Anthropogenic Aluminum Pollution on Different Spatial Distributions and Removal of Natural Waters and Soil in Çanakkale, Turkey(Amer Chemical Soc, 2023) Hızlı, Sezin; Koraoğlu, Aybike Gül; Gören, Ayşegül Yağmur; Kobya, MehmetThe Canakkale-Kirazli region (Turkey) is enriched with minerals, especially aluminum (Al), which dangerously get transported into aquatic media due to several mining and geological activities in recent years. In this study, Al and other potentially toxic metals (PTMs) including B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Si, and Zn, in both water and soil samples, were measured for quality determination. Selected metals were also analyzed by the enrichment factor (EF), the geoaccumulation index (I-geo), the contamination factor (CF), and the pollution load index (PLI) to evaluate both water and soil pollution geogenically or anthropogenically. Also, the metals were clustered to support the pollution source with Pearson's correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA). Forty-five natural water samples and 12 soil samples were collected spatially. To perform pollution assessment, two fundamental treatment processes to remove Al pollution from the sample including the highest Al concentration (38.38 mg/L) in water were applied: (1) precipitation with pH adjustment and (2) removal with ion exchange. The pH values of water samples were changed in the range of 3-9 to test the dissolution of Al. The results demonstrated that the study area was mostly under the influence of geogenic aluminum pollution.Article Citation - WoS: 31Citation - Scopus: 34Insights Into Engineered Graphitic Carbon Nitride Quantum Dots for Hazardous Contaminants Degradation in Wastewater(Elsevier, 2023) Gören, Ayşegül Yağmur; Recepoğlu, Yaşar Kemal; Vatanpour, Vahid; Yoon, Yeojoon; Khataee, AlirezaIncreased environmental pollution is a critical issue that must be addressed. Photocatalytic, adsorption, and membrane filtration methods are suitable in environmental governance because of their high selectivity, low cost, environment-friendly nature, and excellent treatment efficiency. Graphitic carbon nitride (g-C3N4) quantum dots (QDs) have been considered as photocatalysts, adsorbents, and membrane materials for wastewater treatments, owing to their stability, adsorption capacity, photochemical properties, and low toxicity and cost. This review summarizes g-C3N4 QD synthesis techniques, operating parameters affecting the removal performance in the treatment process, modification effects with other semiconductors, and benefits and drawbacks of g-C3N4 QD-based materials. Furthermore, this review discusses the practical applications of g-C3N4 QDs as adsorbents, photocatalysts, and membrane materials for organic and inorganic contaminant treatments and their value-added product formation potential. Modified g-C3N4 QD-based material adsorbents, photocatalysts, and membranes present potentially applicable effects, such as removal of most waterborne contaminants. Excellent results were obtained for the reduction of methyl orange, bisphenol A, tetracycline, ciprofloxacin, phenol, rhodamine B, E. coli, and Hg. Overall, this paper provides comprehensive background on g-C3N4 QD-based materials and their diverse applications in wastewater treatment, and it presents a foundation for the enhancement of similar unique materials in the future.