Adsorption-desorption enhancement in Capacitive Deionization using membranes, resins, polymers and electrode modification

Md Ashique Ahmed, College of Engineering & Science, Louisiana Tech University, Ruston, LA 71270.; Sanjay Tewari, Assistant Professor at College of Engineering & Science, Louisiana Tech University, Ruston, LA 71270.


Capacitive deionization (CDI or CapDI) is a relatively novel technology which has shown increased energy and cost efficiency compared to contemporary technologies such as Reverse Osmosis (RO), Membrane Filtration, Multistage Flash etc. in desalinating water. CDI is an electrochemical process to extract ions from water through the process of adsorption. Carbon based electrodes have been a popular choice among researchers to be used in CDI because of the porous structure and high surface area. These properties increased the effectiveness of CDI process by facilitating mass transport and adsorption of ions. Furthermore, cost requirements of CDI can be lowered by regenerating exhausted electrodes through desorption process. The efficiency of the CDI process can be increased with the use of various membranes, polymers, resins, and modification of electrodes with metal or metal oxides of appropriate zeta potential. This increase is attributed to the enhancement of ion attraction/repulsion capacity in both adsorption and desorption phase. This research focuses on modification of Carbon Aerogel electrodes with metal oxides and compare their performance with unmodified form of the same electrodes in CDI process. Also, the effect of factors such as flow rates, temperature, influent concentration and applied voltage in the CDI process is explored.

Keyword: Desalination, Capacitive deionization, Carbon Aerogel, Adsorption

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