Student Seminar
Name: Mr. Ajeet Kumar Rana
Title: Electrocapacitive deionization for water desalination
Date & Time: Thursday, 25th September 2025 at 4.00 p.m.
Venue: Rajarshi Bhattacharyya Memorial Lecture Hall, Chemical Sciences Building
Abstract:
Freshwater is essential for sustaining life, but global demand for water is expected to rise by 20-25 % by 2050 due to population growth and increasing pollution1. To address this water scarcity, it is essential to remove dissolved salts and contaminants from either sea water or polluted water through desalination.
In this talk, I will discuss mechanistic approaches towards water desalination using electrochemical processes. Electrochemical desalination is superior to conventional membrane and thermal-based techniques due to better cyclic-efficiency and reversibility2. I will focus on capacitive deionization (CDI) techniques in which ions from saline water undergo physical adsorption on the carbon electrodes and results in the formation of electrical-double layer3. Further, due to the limited ion-electrosorption capacity of carbon electrodes in static electrode configurations, flow electrode capacitive CDI is advantageous. Thus, a correlation has been drawn between electrical double-layer capacitance and desalination capacity for static and flow electrodes-based CDI. However, in water with higher salts concentration (>10 g L-1), the charge efficiency and selectivity of carbon-electrodes decrease due to co-ions effect2, 4. To address this, I will also cover desalination using redox-active polymers (a Faradaic approach), which leverage redox reactions and selective hydrogen bonding with ions for effective ion removal in high-salinity conditions5. These insights highlight electrochemical desalination as a next-generation solution with strong potential to address the growing global water crisis.
References:
1. World Resources Institute. (2023). 25 Countries Face Extremely High-Water Stress. Retrieved from https://www.wri.org/insights/highest-water-stressed-countries.
2. Srimuk, P., Su, X., Yoon, J., Aurbach, D. & Presser, V. Charge-transfer materials for electrochemical water desalination, ion separation and the recovery of elements. Nat Rev Mater 5, 517–538 (2020).
3. Sun, K. et al. Electrocapacitive Deionization: Mechanisms, Electrodes, and Cell Designs. Adv Funct Materials 33, 2213578 (2023).
4. Suss, M. E. et al. Water desalination via capacitive deionization: what is it and what can we expect from it? Energy Environ. Sci. 8, 2296–2319 (2015).
5. Su, X. et al. Electrochemically-mediated selective capture of heavy metal chromium and arsenic oxyanions from water. Nat Commun 9, 4701 (2018).