Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 7A Comprehensive Life Cycle Impact Evaluation of Hydrogen Production Processes for Cleaner Applications(Pergamon-elsevier Science Ltd, 2025) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, AliThe worldwide energy demands have greatly increased with urbanization and population growth. Air pollution, acid rain, greenhouse gas emissions, global warming originating from CO2 emissions, depletion of energy supplies, and environmental degradation resulting from climate change are all consequences of using non-renewable fossil fuel-based energy infrastructure. To minimize emissions, renewable energy-based alternative energy sources must be investigated. In this regard, hydrogen (H2) has emerged as a promising fuel to meet energy requirements, and green H2 production with net-zero emissions has gained significant interest in recent years. Therefore, this study uses the life cycle assessment approach to evaluate the atmospheric emissions and environmental impact parameters of the gasification, electrolysis, and dark fermentation-microbial electrolysis hybrid process and assess their sustainability levels, considering the sustainable development goals. Among the studied H2 production processes, the maximum CO2 emission originates from the coal gasification process, accounting for 18.6 kg-CO2/kg-H2, while the alkaline electrolysis process provides the lowest total CO2 emission of 6.39 kg-CO2/kg-H2. Furthermore, the biological-based dark fermentation-microbial electrolysis cell process is a promising option owing to its highest negative biogenic CO2 emission of -68.69 kg-CO2/kg-H2. The environmental impact parameters of the studied processes are calculated considering the emissions, and the highest global warming potential of 21.75 kgCO2-eq./kg-H2 is obtained for the coal gasification process, considering the life cycle assessment coefficients. Overall, the lowest atmospheric emissions and environmental impacts are obtained for the electrolysis process. Consequently, these results revealed that switching from the fossil fuel resources used in the conventional H2 production methods to fully sustainable sources, such as renewables, can make energy production methods entirely sustainable from an environmental point of view.Article Citation - WoS: 1Citation - Scopus: 1Experimental Study for Recovery of Heavy Metals From Contaminated Soil Using Arbuscular Mycorrhizal Fungi(Inderscience Enterprises Ltd, 2025) Budak, Bulent; Onay, Turgut T.; Goren, Aysegul Yagmur; Khalvati, AliSoil micro-organisms like arbuscular mycorrhizal fungi can provide beneficial symbiosis to their host plant and have been adopted to recover metal-polluted soils. This study investigates the removal of heavy metals from soil using phytoremediation in the presence of fungi. The results indicate that the sunflower plant illustrates the highest copper accumulation, with 18.55 mg/kg. In contrast, sunflower and sorghum controls (non-microorganisms) showed weak capability to transfer copper through plant biomass with 0.91 and 0.97 mg/kg, respectively. Both plants showed that phytoremediation can be a promising approach to providing sustainable solutions for soil heavy metal contamination in the presence of fungi.Article Citation - WoS: 6Citation - Scopus: 6A New Electro-Biomembrane Integrated Renewable-Based System To Produce Power, Fresh Water and Hydrogen for Sustainable Communities(Elsevier, 2025) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, AliAs the consequences of global warming become more severe, it is more crucial than ever to capitalize on all locally accessible potential renewable energy sources and produce sufficient useable energy outputs to meet community demands while causing the least damage to the ecosystem. Therefore, this paper focuses on a unique parabolic trough collector solar system-powered electro-biomembrane unit that combines a heat and power system with fresh water, electricity and hydrogen production. The proposed integrated system contains the following subsystems: a combining parabolic trough collector solar system, an organic Rankine cycle, a steam Rankine cycle, a multi-stage flash desalination system, and an electro-biomembrane H2 and freshwater production system. A thorough analysis and parametric research are performed on the multigeneration system to determine how important characteristics affect system performance and evaluate the energy and exergy efficiencies, and exergy destruction levels for particular system elements. The study results show that solar irradiation is the most critical parameter for improving system performance. The highest freshwater production of 1,303,333.3 L/day is observed at the solar irradiation of 935,768 kWh/day. Furthermore, the combined output of three electricity production technologies exceeds 2,000,000 kWh/day, highlighting the ability of the system to harness solar thermal energy effectively. The study findings indicate that using solar power and biomass as renewable energy sources, the proposed integrated system provided 328.56 kg of biohydrogen per day. Overall, the energy and exergy efficiencies of the integrated system are obtained as 34.3 and 29.5 %, respectively.Article Citation - WoS: 7Citation - Scopus: 7Hydrogen Production From Energetic Poplar and Waste Sludge by Electrohydrogenesis Using Membraneless Microbial Electrolysis Cells(Pergamon-elsevier Science Ltd, 2024) Goren, A. Yagmur; Kilicaslan, A. Faruk; Dincer, Ibrahim; Khalvati, AliMembraneless microbial electrolysis cells (MECs) are potentially considered to produce biohydrogen (bioH2) in a green manner and simultaneously minimize agricultural and wastewater facility wastes. However, effective, sustainable, and cost-effective system configuration and improvement of operating variables, working at ambient conditions, are needed to make the MEC a sustainable process. Therefore, this study investigates the bioH2 production from poplar leaves and anaerobic sludge mixture by incorporating nanomaterials comprising Al2O3, MgO, and Fe2O3 metal oxides at various dosages. Moreover, the effects of applied cell voltage (0.5-1.5 V) and inoculum amount (20-40 mL) on bioH2 production and organic matter removal performance are evaluated. The maximum bioH2 production value is 417 mL at an applied voltage of 1.5 V with a chemical oxygen demand (COD) removal efficiency of 37.6 % under operating times of 5 min using 40 ml of inoculum. The bioH2 production of the MEC system is reduced with the decrease in inoculum amount. The highest bioH2 production of 828 mL is obtained at improved conditions in the presence of 1 g of Fe2O3 metal oxide. Overall, this study provides the potentiality of simultaneous waste minimization and bioH2 production under ambient conditions that highlight the waste-to-energy pathway for membraneless and green bioelectrochemical process.Article Citation - WoS: 14Citation - Scopus: 17Cleaner Production of Biohydrogen Using Poplar Leaves: Experimental and Optimization Studies(Elsevier Sci Ltd, 2024) Goren, A. Yagmur; Kenez, Muratcan; Dincer, Ibrahim; Khalvati, AliBiohydrogen (bioH2) is recognized as a potential carbon-neutral energy vector, and developing novel methods has received increasing attention with a prime goal of producing H2 more efficient and cost effective manner. This study aimed to develop a unique reactor to investigate dark fermentative H2 production from poplar biomass using commercially available and inexpensive microorganism cultures. Therefore, six factors of the Box-Behnken design (BBD) were performed to evaluate the individual and combined effects of operational param-eters: acid concentration (2-10%), biomass concentration (2-10 g), initial pH (5-8), temperature (30-40 degrees C), mixing ratio (150-350 rpm), and microorganism concentration (2-6 g) on bioH2 production. Among the oper-ational parameters, the acid concentration was the most effective parameter on bioH2 production. The bioH2 production increased from 11.33 to 18.15 mg/g biomass with increasing acid concentration from 6 to 10%. Moreover, the optimum levels of operational variables were as follows: acid concentration of 9.9%, biomass amount of 2 g, pH of 6.56, temperature of 35 degrees C, mixing ratio of 345 rpm, and microorganism amount of 4.5 g for the highest bioH2 production of 20 mg/g-biomass according to the experimental design. Consequently, the bioH2 production performance of the dark fermentation process showed that bioH2 production from poplar biomass using commercially available microorganisms had a competitive advantage.Review 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.