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  • Review
    Citation - Scopus: 7
    Ion Exchange Membranes for Reverse Electrodialysis (red) Applications - Recent Developments
    (Amirkabir University of Technology - Membrane Processes Research Laboratory, 2021) Eti,M.; Othman,N.H.; Guler,E.; Kabay,N.
    The innovative membrane-based technology called reverse electrodialysis (RED) is capable of producing electrical power from the controlled mixing of two aqueous streams of different salinity. There has been tremendous progress so far in the development of RED process in terms of system development, spacer design, membranes properties and operational conditions optimization. Among those, characteristics of the ion exchange membranes are found to be the critical element affecting the performances of RED process. In this respect, a brief overview of the latest developments in ion exchange membranes were presented in this review, focussing on their properties and performances in RED applications. The recent developments of nanocomposite and ion selective membranes, particularly pore filling ion exchange membranes due to their high performances and inexpensive fabrication cost were also summarized. Shortly, fouling problem for the ion exchange membranes employed in the RED system was mentioned. © 2021 Amirkabir University of Technology - Membrane Processes Research Laboratory. All rights reserved.
  • Book Part
    Citation - Scopus: 12
    Water Flux and Reverse Salt Flux
    (Elsevier, 2018) Koseoglu,H.; Guler,E.; Harman,B.I.; Gonulsuz,E.
    Following the increase in the world population and the demand for economic development, the need for energy has increased day by day. Rapidly increasing global energy consumption is supplied mainly by fossil fuels bearing the risk of exhaustion with decreasing reserves, which now have the effect of carbon emissions and greenhouse gases. These concerns lead humanity to significantly reduce the use of fossil fuels. Salinity gradient energy (SGP), a type of hydroelectric energy, also has a high potential to displace fossil fuels. SGP is less periodic than sources like wind and solar energy. The osmotic pressure gradient energy uses the released energy during mixing of the water currents with different salinity The Gibbs free energy from mixing two solutions of different concentrations is an unnoticed source of energy. Salinity gradient energy, also referred to as osmotic energy or blue energy, can be derived from natural sources such as clean river water, salt water, and desalination of seawater. Various approaches have been developed to capture salinity gradient energy, but the most promising are pressure-retarded osmosis (PRO), reverse electrodialysis (RED) and forward osmosis (FO) processes. In this chapter theoretical approaches derived from the current literature is presented for the deep conceptual understanding of the water flux and reverse salt flux issues. © 2018 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 18
    Citation - Scopus: 20
    Investigations on the Effects of Operational Parameters in Reverse Electrodialysis System for Salinity Gradient Power Generation Using Central Composite Design (ccd)
    (Elsevier, 2022) Altiok, Esra; Kaya, Tugce Zeynep; Othman, Nur Hidayati; Kinali, Orhan; Kitada, Soma; Guler, Enver; Kabay, Nalan
    Reverse electrodialysis (RED) can be utilized for the production of renewable energy from salinity gradients. However, there are many key parameters that could influence the performance of RED. This study investigates the use RSM for development of a predictive power density (PD) and open-circuit voltage (OCV) model for the RED system. A three-factor central composite design (CCD) was used to quantify the effects of flow velocity (X-1), salinity ratio (X-2), and number of cell pairs (X-3) towards PD and OCV. A total of 17 experimental data were fitted and ANOVA was used to validate the accuracy of the models. 3D and surface plots were created to foresee the optimal levels of each variable. It was found that flow velocity and salinity ratio have the most dominant influences on the RED performances as compared to number of cell pairs. The predicted PD and OCV values were found to be reasonably fit with the experimental data, validating the predictability of applied models. Therefore, this study suggests that CCD can be considered an effective tool for evaluating and optimizing the RED system using a minimum number of experiments.