Browsing by Author "Cihanoglu, Aydin"

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Effect of Asymmetric Feed Flow Rate and Temperature on Reverse Electrodialysis: A Response Surface Methodology Approach
(Elsevier, 2025) Gul, Taha Furkan; Gonlugur, Miray Emreol; Guler, Enver; Cihanoglu, Aydin; Kabay, Nalan; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Reverse electrodialysis (RED) has the potential to generate sustainable energy by utilizing the salinity gradient potential between natural water sources with different salinities, such as river water and seawater. It is essential to comprehend the RED process's characteristics and optimize operational parameters to enhance its commercial viability. This study investigated the effects of varying inlet feed flow rates and temperatures on RED performance using Response Surface Methodology. Unlike conventional approaches, where inlet flow rates of seawater and river water solutions are typically kept equal, this research explores their diverse combinations. Key performance metrics of RED, including power density and open circuit voltage, were evaluated. Moreover, the impacts of different feed flow rates and temperatures on ohmic and non-ohmic resistances were thoroughly examined. The findings underscore significant interactions between feed flow rates, temperature, and RED performance outputs, providing insights essential for optimizing RED operations and enhancing its practical application in sustainable energy solutions.
Citation - WoS: 4
Citation - Scopus: 4
Further Development of Polyepichlorohydrin Based Anion Exchange Membranes for Reverse Electrodialysis by Tuning Cast Solution Properties
(Mdpi, 2022) Eti, Mine; Cihanoglu, Aydin; Guler, Enver; Gomez-Coma, Lucia; Altiok, Esra; Arda, Muserref; Kabay, Nalan; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Recently, there have been several studies done regarding anion exchange membranes (AEMs) based on polyepichlorohydrin (PECH), an attractive polymer enabling safe membrane fabrication due to its inherent chloromethyl groups. However, there are still undiscovered properties of these membranes emerging from different compositions of cast solutions. Thus, it is vital to explore new membrane properties for sustainable energy generation by reverse electrodialysis (RED). In this study, the cast solution composition was easily tuned by varying the ratio of active polymer (i.e., blend ratio) and quaternary agent (i.e., excess diamine ratio) in the range of 1.07-2.00, and 1.00-4.00, respectively. The membrane synthesized with excess diamine ratio of 4.00 and blend ratio of 1.07 provided the best results in terms of ion exchange capacity, 3.47 mmol/g, with satisfactory conductive properties (area resistance: 2.4 omega center dot cm(2), electrical conductivity: 6.44 mS/cm) and high hydrophilicity. RED tests were performed by AEMs coupled with the commercially available Neosepta CMX cation exchange membrane (CEMs).
Citation - WoS: 3
Citation - Scopus: 3
Synthesis of Silver Nanoparticle-Immobilized Antibacterial Anion-Exchange Membranes for Salinity Gradient Energy Production by Reverse Electrodialysis
(Amer Chemical Soc, 2024) Eti, Mine; Cihanoglu, Aydin; Hamaloglu, Kadriye Ozlem; Altiok, Esra; Guler, Enver; Tuncel, Ali; Kabay, Nalan; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Biofouling, stemming from the attachment of living microorganisms, such as bacteria, which form resilient biofilms on membrane surfaces, presents a significant challenge that hampers the efficiency of anion-exchange membranes (AEMs) in reverse electrodialysis (RED) applications. This limitation curtails the generation of electrical power from salinity gradients, which notably is a sustainable form of energy known as osmotic energy. RED stands as a clean and promising process to harness this renewable energy source. This study aimed to impart antibacterial activity to synthesized AEMs by using silver nanoparticles (AgNPs). For that purpose, AgNPs were synthesized at 30 degree celsius using two different pH values (6.0 and 9.0) and immobilized into synthesized AEMs using the dip-coating technique. In nanoparticle synthesis, ascorbic acid and trisodium citrate were used as a reductant and a stabilizer, respectively, to take control of the particle size and agglomeration behavior. The results indicated that AgNPs synthesized at pH 6.0 were dispersed on the AEM surface without agglomeration. The stability of AgNPs immobilized on the membrane surface was tested under low- and high-saline solutions. The antibacterial activities of AEMs were determined with the colony-counting method using Gram-negative (Escherichia coli) bacterial suspension. The viability of bacteria dramatically decreased after the immobilization of AgNPs in the AEMs. In the short- and long-term RED tests, it has been observed that the AEMs having AgNPs have high energy-generating potentials, and power density up to 0.372 W/m(2) can be obtained.
The Impact of Quaternization Degree in Polyepichlorohydrin-Based Anion Exchange Membranes on Salinity Gradient Energy Generation by Reverse Electrodialysis
(Elsevier, 2025) Cihanoglu, Aydin; Guler, Enver; Kabay, Nalan; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
Anion exchange membranes with tailored fixed-charge densities can improve monovalent ion selectivity and performance in reverse electrodialysis for salinity gradient power generation. In this study, poly(epichlorohydrin) was blended with polyacrylonitrile and quaternized with 1,4-diazabicyclo[2.2.2]octane at three different molar ratios to produce AEMs with systematically varied quaternization degrees via a one-step amination/ crosslinking procedure. The resulting membranes were characterized for their physicochemical, electrochemical, and RED performance using ATR-FTIR, XPS, SEM, AFM, water uptake, swelling degree, contact angle, surface zeta potential, ion exchange capacity, fixed charge density, and electrical resistance. Higher quaternization increased the IEC, reduced resistance, and shifted surface charge, leading to improved stack power output in model NaCl solutions. In the presence of Na2SO4, power loss was reduced for more highly quaternized membranes, indicating enhanced exclusion of divalent anions (SO42-) and reduced uphill transport. Fouling tests with humic acid/fulvic acid mixtures showed greater stability for quaternized membranes compared to a commercial benchmark. Moreover, stability tests conducted on fouled membranes revealed that the tailor-made membrane exhibits superior durability and lower fouling-induced power loss than commercial Fujifilm Type II AEMs. Overall, these results demonstrate that tuning the degree of quaternization is an effective strategy to balance conductivity and ion selectivity in AEMs for RED applications.