Device Would Provide Greener Alternative to Extract Freshwater from Saltwater
An article published by Clarkson Chemical Engineering graduate student, Gowri Mohandass, was highlighted on the cover of the December issue of the American Chemical Society’s Environmental Science & Technology: Engineering journal. The featured work uses a sunlight-powered electrochemical cell for separating salt from water. Mohandass, a Karel Czanderna and Dan Shirkey Ignite Fellow at Clarkson University, is a researcher in the labs of Professors Taeyoung Kim and Sitaraman Krishnan who are co-authors of the article. The team has developed a redox-flow system for continuous freshwater production using a relatively inexpensive solar cell constructed using titanium dioxide and carbon electrodes.
Electrochemical desalination of water involves the migration of sodium ions of the salt toward the negative electrode and the chloride ions toward the positive electrode under an applied voltage. Rather than using a separate solar panel comprising, for example, silicon solar cells, to generate the required voltage, the Clarkson researchers built an integrated device wherein one of the two electrodes of the electrochemical cell is photovoltaic. Their process did not use volatile organic solvents such as acetonitrile, which were found necessary in previous studies (but are toxic). The cell design was such that the voltage and current generated by sunlight were sufficient to produce potable water at relatively high flow rates. Furthermore, their device is expected to be cheaper to install than systems based on silicon solar cells.
Around two-thirds of the world lives under severe water scarcity for at least one month a year. Desalination is a practical solution to extract freshwater from saltwater. Existing thermal desalination techniques require high capital expenditure and depend on fossil fuel-powered energy sources. Light-powered electrochemical desalination can be a greener alternative.
The article is available at https://pubs.acs.org/doi/10.1021/acsestengg.1c00266.
The Clarkson Ignite Research Fellowship program aims to drive innovative research that can potentially impact society at the national and international levels. The program recruits and supports highly talented PhD students to help pursue these innovative research projects.