Redox-active materials for electrochemical separation applications
The separation of ions from aqueous (water) solutions is desirable for many real-life applications.
Seawater and brackish water desalination are currently achieved mostly by Reverse Osmosis (RO) and thermal distillation. While thermal distillation is easily scaleable, it is energy inefficient due to the heat required to evaporate water cannot be recovered. Reverse Osmosis, on the other hand, is currently the most energy-efficient technology but should be operated at large scales to reduce the cost of desalinated water, which requires a substantial initial capital investment. Besides, RO is limited by the salinity of the feedwater due to the mechanical integrity of the RO membranes.
At Smith Research Group, we are developing new technology that uses materials found in batteries for desalination purposes. Upon applying a current, these materials can capture alkali and/or alkaline earth ions via redox reactions, which is known as intercalation process. When the current direction is switched, the materials can release the captured ions reversibly and can be reused multiple times. This technology is often referred to as Faradaic deionization (FDI). It is unlikely to be limited by the feedwater salinity because the materials can store ions at a concentration much larger than the salt concentration found in seawater. However, the main limitation of this technology is its energy efficiency, which we are actively working to improve.
Another interesting feature of Faradaic deionization is that the redox-active material often has different preferences towards different ions, which we referred to as selectivity bias. For example, it can prefer to intercalate sodium while rejecting calcium and magnesium. This gives us opportunities to select or develop materials that are suitable for specific applications, such as selective removal of sodium, lithium, or nutrient recovery.
Immersed Boundary Method Library in OpenFOAM
During my undergraduate, I enjoyed studying computational fluid dynamics (CFD), especially Fluid-structure Interaction (FSI) types of problems as they are very popular in practical applications. Most of my simulations back then were performed with OpenFOAM open-source software. OpenFOAM is one of the most robust toolboxes for fluid flows simulation. It offers a variety of solvers for incompressible and compressible flows. Being developed by C++ experts, prof. Hrvoje Jasak and Henry Weller, OpenFOAM has a very beautiful architecture that enables easy customization of the existing solvers as well as the development of tailored solvers for your specific CFD problems.
My undergraduate thesis was developing a new Immersed Boundary Method (IBM) library and an associated solver for particulate flows, which was then applied for studying the so-called inertial focusing phenomenon in microchannels. My work was inspired by research led by prof. Jongyoon Han at MIT:
The OpenFOAM community is very active and my journey was made much easier thanks to many tutorials out there on Youtube as well as cfd-online.com website. I hope that I would be able to contribute to the community with some tutorials about developing new solvers/libraries in OpenFOAM. Unfortunately, I was overwhelmed with research ever since starting grad school and I wasn't able to make that happen yet.
Below are some simulations performed using my IBM libraries:
Drafting, Kissing, Tumbling of two spherical particles (or DKT motion), 2D and 3D simulations
Periodic boundary condition for Immersed Boundary Objects enable simulation of Inertial Focusing
Other simulations