Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Khalvati, AliDepartment: search.filters.department.İzmir Institute of Technology

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Now showing 1 - 4 of 4
  • Article
    Citation - WoS: 3
    Citation - Scopus: 7
    A Comprehensive Life Cycle Impact Evaluation of Hydrogen Production Processes for Cleaner Applications
    (Pergamon-elsevier Science Ltd, 2025) Goren, A. Yagmur; Dincer, Ibrahim; Khalvati, Ali
    The 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: 1
    Citation - Scopus: 1
    Experimental 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, Ali
    Soil 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: 6
    Citation - Scopus: 6
    A 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, Ali
    As 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: 14
    Citation - Scopus: 17
    Cleaner Production of Biohydrogen Using Poplar Leaves: Experimental and Optimization Studies
    (Elsevier Sci Ltd, 2024) Goren, A. Yagmur; Kenez, Muratcan; Dincer, Ibrahim; Khalvati, Ali
    Biohydrogen (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.