Papers in 2025
Nanoarchitectonics approach to graphite/starch-supported bioelectrode for enhanced supercapacitor performance
In this study, a novel bioelectrode composed of commercial potato starch and graphite was synthesized and evaluated for supercapacitor applications. The developed electrode exhibited a high specific capacitance of 355.6 F/g at 0.5 A/g and demonstrated exceptional cyclic stability with 93.5% retention after 5000 charge/discharge cycles.
By increasing graphite content, the resulting porous structure enhanced both electrical conductivity and ion diffusion capacity of the electrode. This bioelectrode, combining low-cost, biodegradable components with high electrochemical performance, stands as a strong candidate for use in portable electronics, hybrid vehicles, and grid-scale energy storage systems—advancing the goals of sustainable and circular energy technologies.
A comprehensive life cycle impact evaluation of hydrogen production processes for cleaner applications
This study evaluates and compares three different hydrogen production routes—coal gasification, water electrolysis, and a hybrid dark fermentation–microbial electrolysis cell (DF-MEC)—from a life cycle assessment (LCA) perspective. The analysis encompasses atmospheric emissions and environmental impact categories to determine each method’s sustainability level.
The findings indicate that the electrolysis method yields the lowest total CO₂ emission (6.39 kg-CO₂/kg-H₂) and environmental burden, while the DF-MEC process achieves the highest negative biogenic CO₂ emission (−68.69 kg-CO₂/kg-H₂). In contrast, coal gasification exhibits the highest environmental impact and is considered the least sustainable scenario.
This comprehensive evaluation contributes to a deeper understanding of the environmental consequences of hydrogen production technologies and supports the global transition toward clean and sustainable energy systems.
Esterase-mediated degradation of dibutyl and diethylhexyl phthalates in aqueous and soil systems
A research article titled “Esterase-mediated degradation of dibutyl and di(2-ethylhexyl) phthalates in aqueous and soil systems” has been published in Chemosphere, authored by Dr. Esin Balcı (Research Assistant, Department of Environmental Engineering), Prof. Dr. Aysun Sofuoğlu (Faculty Member, Department of Chemical Engineering), and Prof. Dr. Gülşah Şanlı-Muhammed (Faculty Member, Department of Chemistry).
In this study, the degradation of phthalates—known endocrine-disrupting compounds—was investigated in both aqueous and soil systems using esterase enzymes derived from Geobacillus sp., isolated from the Balçova geothermal resources in İzmir, as well as esterase enzymes from Bacillus subtilis.
Derivation of soil hydraulic properties (SHPs) using a Physics-Based inverse calibration method and International soil moisture network database
This study used extensive soil moisture records to estimate “inverse-calibrated Soil Hydraulic Properties (SHPs)” using a multi-processing technique via high-performance computing clusters. Within this objective, a mass conservative numerical model was developed to solve the one-dimensional Richards Equation incorporating two different soil hydraulic models: the well-known van Genuchten Mualem (VGM) model and the relatively new Fredlund-Xing-Wang (FXW). A multiprocessing version of the Differential Evolution Algorithm (DEA) optimization technique was used for inverse calibration of the soil hydraulic parameters. For FXW, calibration statistics were calculated as means of the KGE’ (0.89 ± 0.1 and 0.83 ± 0.23), R (0.89 ± 0.1 and 0.85 ± 0.21) and ubRMSE (0.017 ± 0.01 and 0.015 ± 0.02) for the depths 50 and 100 cm, respectively. For VGM, calibration statistics were found as means of the KGE’ (0.87 ± 0.11 and 0.78 ± 0.22), R (0.90 ± 0.08 and 0.86 ± 0.17) and ubRMSE (0.019 ± 0.01 and 0.017 ± 0.01) for the same depths, respectively. The employed methodology had highly promising statistical performance for both FXW and VGM to derive SHPs. A comprehensive validation methodology was used to evaluate the reliability of derived SHPs. Correlation analysis showed that derived SHPs strongly correlated with the soil properties and environmental variables. Further, as a validation procedure, initial investigations were also conducted to explore the spatial transferability of the parameters. Despite the use of basic k-means clustering, the resulting soil hydraulic datasets showed statistical similarity or even improvement to hyper-resolution maps used in the literature. While the simulation model of the methodology has certain assumptions and limitations, this study proves that the ISMN database can be used to derive soil hydraulic properties and transfer these parameters to locations other than the calibration points. This study shows that FXW is a promising hydraulic model for the determination of soil moisture at root zone within the complete moisture range. The methodology can also be readily extended to other established soil moisture monitoring networks and potentially extended versions of “inverse-calibrated SHPs” and trained pedotransfer functions are considered to be valuable tools to estimate soil moisture profiles at the root zone.
Surface sediments as a sink and risk source for legacy POPs during waste management practices
“Surface sediments as a sink and risk source for legacy POPs during waste management practices” has been published in Environmental Pollution.
The study found that coastal sediments in a shipbreaking zone in Türkiye (Aliağa, İzmir) have alarmingly high levels of PCBs and PBDEs — persistent organic pollutants (POPs). These activities turn sediments into long-term pollution hotspots, posing ecological risks.
This work highlights the need for stricter waste practices and global action on POPs.
Life cycle assessment of black tea production and consumption in Türkiye: Insights from waste management scenarios
This study conducts a life cycle assessment (LCA) of tea production and consumption in Türkiye, the world leader in per capita tea consumption. Aiming to identify environmental hotspots and propose sustainable solutions, a cradle to-grave LCA was performed using CCaLC2 software, CML methodology, and the Ecoinvent 3.0 database. It covers cultivation, processing, transportation, and consumption stages, focusing on key environmental indicators like carbon footprint and acidification potential. The results reveal that consumption dominates the environmental footprint (91%) due to energy-intensive brewing methods. Cultivation and transportation contribute minimally (4% each). This highlights the need for promoting energy-efficient brewing practices and consumer adoption of renewable energy sources. The study also explores the environmental implications of different waste management strategies. Composting emerged as the most beneficial approach for reducing the carbon footprint and photochemical oxidants creation, while incineration might be preferable for other impact categories. This study underscores the importance of addressing energy consumption during tea brewing and encouraging renewable energy use among consumers. Additionally, it promotes composting as a crucial waste management strategy for a more sustainable tea value chain in Türkiye. These findings offer valuable insights for policymakers, industry players, and tea drinkers to make
informed decisions that minimize environmental impact.
A New Electro-Biomembrane Integrated Renewable-Based System to Produce Power, Fresh Water and Hydrogen for Sustainable Communities
As global warming intensifies, the need for efficient and sustainable energy solutions is more critical than ever. In our latest study, we developed a parabolic trough collector (PTC) solar system-powered electro-biomembrane unit, integrating solar thermal energy and biomass to simultaneously produce freshwater, electricity, and biohydrogen. This multi-generation system combines five key subsystems: a PTC solar system, organic Rankine cycle, steam Rankine cycle, multi-stage flash desalination unit, and an electro-biomembrane reactor. Our findings highlight the significant role of solar irradiation in system performance, demonstrating the ability to harness renewable energy efficiently. Notably, the system achieves a biohydrogen production of 328.56 kg per day, showcasing its potential for sustainable hydrogen generation while contributing to clean water and power production.
The role of effective catalysts for hydrogen production: A performance evaluation
Hydrogen (H2) is a promising clean energy carrier, offering a sustainable alternative for fuel, storage, and industrial applications. However, large-scale H2 production remains limited by high costs and low yields. Recent advancements in catalyst technologies have significantly improved efficiency in biological, thermochemical, and water-based processes. Catalysts such as iron, nickel, titanium oxide, and silver have been shown to enhance H2 production rates, while optimizing reactor design, catalyst dosage, temperature, and pH further improves performance. In dark fermentation, the use of metal catalysts increases biological H2 yield by 3.2–38%, highlighting their potential in boosting production while minimizing environmental impact. This study emphasizes the crucial role of catalysts in advancing sustainable hydrogen production and identifies key challenges for future research and large-scale implementation
Experimental study for recovery of heavy metals from contaminated soil using arbuscular mycorrhizal fungi
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.
A comparative evaluation of dark fermentative bioreactor configurations for enhanced hydrogen production
The growing demand for renewable energy has increased interest in biohydrogen (bioH2) production as a clean and sustainable fuel alternative. Among various production methods, dark fermentation offers a promising pathway for large-scale and cost-effective bioH2 production. This study examines different bioreactor configurations, including anaerobic sequencing batch, continuous stirred, up-flow, fixed-bed, and membrane reactors, to evaluate their efficiency in bioH2 production. The findings indicate that continuously stirred reactors are the most widely used due to their economic feasibility, while membrane and fixed-bed reactors achieve higher bioH2 yields. By performing a bibliometric analysis, this review provides a comprehensive overview of historical and current developments in bioreactor technologies, addressing key parameters that influence performance and strategies for enhancing efficiency