In a new study, mechanical engineers focused on fluid movement rather than new materials to make saltwater desalination work better. Researchers increased the extent of seawater desalination five times over their non-channeled counterparts to reach salinity levels below the freshwater threshold by adding microchannels to the interior of battery-like electrodes made of Prussian blue, an intense blue pigment that is frequently used in art and also has special chemical properties.
A chemical analog to Prussian blue was used in the study, which was led by graduate student Vu Do and professor Kyle Smith of mechanical engineering and science at the University of Illinois at Urbana-Champaign. Desalination, energy conversion and storage, CO2 conversion and capture, environmental remediation, and resource and nutrient recovery are potential applications of the findings.
Energy and Environmental Science is the journal that published the study.
“The purpose of the Navy grant utilized to support this study is to offer a portable device to give water to military personnel in small expeditionary units by desalinating two to four gallons per hour while using diesel fuel as the power source.”
Science professor Kyle Smith
Smith stated, “In previous work, we predicted that this method could be used for desalination, but nobody had validated seawater-level desalination in the laboratory.” In the meantime, we discovered that notwithstanding the particular sort of material utilized in the cathodes, the framework’s arrangement additionally matters.”
To enhance the flow within their brand-new electrodes, the team made use of laser-engraved microchannels. A single microchannel is shown from the side, right, and above, respectively. Credit: Smith research group, University of Illinois Urbana-Champaign.
According to the findings of the Smith research group at the University of Illinois at Urbana-Champaign, the Prussian blue analog material functions by retaining positively charged ions, such as sodium, within the crystal structure of the pigment. However, it has the potential to develop into something resembling a trap, in which a web of tiny, charged pore spaces on the molecular scale inside the electrode prevents the ions from entering. The team discovered that in order to maintain continuous desalination, they would need to use specialized equipment to perform complex valve switching and current synchronization inside the flow cell. This would make the system less efficient.
According to the researchers, they are able to provide the fluids with a clear path to pass through without losing the ability to extract salt ions from the water by engraving multiple 100-micrometer-wide channels onto the 5-centimeter-sized electrode. These channels are about the width of a human hair.
According to the researchers, scaling up is the next step because the setup used in this study can desalinate seawater that has been prepared in the laboratory at a rate of milliliters over the course of an hour.
Professor Kyle Smith, left, and graduate students Irwin Loud and Vu Do. Credit: Michelle Hassel
Michelle Hassel Smith stated, “The goal of the Navy grant used to fund this study is to provide a portable device to supply military troops in small expeditionary units with water by desalinating two to four gallons per hour using diesel fuel as a power source.” Naturally, our group is interested in much broader uses for these battery-like devices, but scaling up will be a necessary step.”
“One momentous part of this study is the mechanical design edge that we give,” Do said. ” Materials and their chemistry receive a lot of attention in the research community. In any case, we’ve shown that the liquid mechanics of the framework matter a ton to capitalize on an extraordinary material when you coordinate it suitably.”
Smith research group individuals Irwin Boisterous and Erik Reale additionally added to the review.
More information: Vu Quoc Do et al, Embedded, micro-interdigitated flow fields in high areal-loading intercalation electrodes towards seawater desalination and beyond, Energy & Environmental Science (2023). DOI: 10.1039/D3EE01302B
