Overview of Different Architectures of Capacitive Deionization Cells and Comparison of their Performance in Water Desalination

Considering the necessity of access to fresh water for sustainable growth and development, the use of various technologies for desalination of salt water is one of the solutions to increase access to fresh water. Various problems of conventional water desalination methods have led to the emergence of new methods such as capacitive deionization technology. CDI technology is an emerging electrochemical adsorption technology to remove water-soluble ions. In recent years, the development of this technology has attracted the attention of many researchers from the functional and economic point of view. Recent research results show that to overcome the challenges of CDI technology, focusing on two areas of effective porous electrodes and applied architectures can be more effective than other solutions. Therefore, this article provides a brief overview of CDI technology and investigates its emergence, progress, and challenges. Furthermore, various types of structures with capacitive electrodes have been introduced along with their unique features, drawbacks, and advantages. Also, this article describes in detail the quantitative and qualitative performance comparison of different geometries of CDI technology, such as flow-by CDI, flow-through CDI, MCDI, FCDI and i-CDI. The results show that, currently, CDI technology using nanostructured carbon electrodes is economical for the deionization of low and medium salinity waters (3 g/L). Despite numerous challenges, capacitive deionization technology has the potential to provide a sustainable source of fresh water in the future. This technology offers a clean and environmentally friendly solution, with low energy consumption and economical operation.