Investigation of desalination performance of capacitive deionization technology

Download
2019
Özkul, Selin
Capacitive deionization (CDI) is one of the emerging technologies developed with the purpose of water desalination. CDI technology is based on ion electrosorption at the surface of electrically charged electrode couples that are commonly comprised of porous carbon materials. Along with the continuous increase in the global fresh water demand, CDI technology becomes more prominent as an energy efficient and cost-effective water purification process. In this study, ion removal capacity of the CDI process was investigated under various operational conditions using different carbon based electrodes. For this purpose, carbonaceous supercapacitor electrodes were developed from commercially available, cost-effective activated carbon and graphene materials, and the use of these materials for deionization was explored in detail. The porosity, morphology and chemical nature of the carbonaceous materials were analysed, and it has been found that both materials are porous with different structural properties. Electrochemical properties of the fabricated electrodes were also investigated, and both electrodes showed good electrochemical reaction kinetics and follow electric double layer mechanism during electrosorption process. Furthermore, deionization performances of the fabricated carbonaceous electrodes were evaluated in a laboratory scale CDI unit. The electrosorption behavior of carbonaceous electrodes was analyzed at different electrical potentials and water flow rates, and impact of operating parameters on the sorption capacity was investigated. At a flow rate of 20 ml/min and at a potential of 2.0 V, the maximum electrosorptive capacities of 8.9 μmol/g and 10.7 μmol/g were obtained from activated carbon and graphene electrodes, respectively. In addition, monovalent and divalent ion removal capacities of the fabricated electrodes were determined using solutions with different initial salt concentrations. Graphene-like material with high mesoporosity showed better deionization performance at high concentrations considering removal of both monovalent and divalent ions, yet microporous structured activated carbon reached higher ion removal capacity for monovalent ions at lower salt concentrations.

Suggestions

Enhancing capacitive deionization technology as an effective method for water treatment using commercially available graphene
DURSUN, Derya; OZKUL, Selin; YÜKSEL, Recep; Ünalan, Hüsnü Emrah (IWA Publishing, 2017-02-01)
In recent years, capacitive deionization (CDI) has been reported as one of the emerging technologies developed with the purpose of water desalination. This work is aimed at the integration of supercapacitor electrodes for efficient removal of ions from water, and thus to achieve an energy efficient, and cost-effective water treatment process. Our objective is to transfer the vast knowledge of supercapacitors and advanced materials in area of water treatment to enhance the knowledge of the CDI process. Towar...
Comprehensive modeling of heat and mass transport in a micropillar evaporator
Yuncu, Göksel; Dursunkaya, Zafer; Akkuş, Yiğit; Department of Mechanical Engineering (2022-4-05)
Thin-film evaporation and the replenishing capillary liquid flow have paramount importance for various technological applications spanning from desalination to electronics cooling. With the developments enabling faster and cheaper yet more precise fabrication, evaporators with micropillar arrays have attracted substantial attention to sustain efficient evaporation fed by passive liquid transport. Although considerable effort has been devoted to designing optimized wicks, the full picture is still blurry due...
Investigation of Self-Excited Ultrahigh Speed Induction Generators for Distributed Generation Systems
Jardan, Rafael K.; Varga, Zoltan; Nagy, Istvan (2011-09-10)
Application of ultra high speed induction generators (IG) in a system developed for utilization of renewable and waste energies that can be applied in Distributed Generation System is presented. The energy conversion is made by a turbine-generator set. For the electromechanical energy conversion application of special high speed induction generators has been studied and described in the paper. The design and analysis of the system are relied on computer simulation techniques verified by test results.
Evaluation of Grid-Connected PV Converter Power Module Technologies in Terms of Efficiency, Initial Cost, and Return on Investment Time
Oztoprak, Oguzhan; Hava, Ahmet Masum (2019-01-01)
The voltage source converter (VSC) of the grid connected photovoltaic (PV) systems is the most technological component in a PV system and contributes to 5-15% of the whole investment. As the cost and energy efficiency of a VSC are two factors that determine the total system economics, the system total cost of ownership (TCO) should be optimized during the VSC design. This paper provides a design methodology for grid connected VSCs considering TCO, the return on investment (ROI) and payback period (PP) as th...
Investigation of doped and undoped VOxfilms for terahertz microbolometer applications
Atik, Bahar; Dirican, Emrah; Demirörs, Oytun; Altan, Hakan; Esentürk, Okan; Ylldlrlm, Mustafa; Akın, Tayfun (2021-01-01)
The microbolometer technology has proved its potential in the Infrared (IR) region due to its low fabrication costs, and room temperature operation, making this technology desirable to be used in various applications, and this interest has recently expanded into the Terahertz (THz) region as well. The detection in microbolometers is achieved through the absorption of THz radiation which subsequently heats up and is sensed by the temperature sensitive material at the core of the device. This temperature sens...
Citation Formats
S. Özkul, “Investigation of desalination performance of capacitive deionization technology,” M.S. - Master of Science, Middle East Technical University, 2019.