Johan Nordstrand
About me
I am a researcher in computational materials chemistry at Kemikum in Stockholm University. My research focuses on water purification with capacitive deionization (CDI), and I am especially interested in understanding how contaminants can be selectively removed and recovered from water.
During my postdoc I worked in multi-scale simulations at Stanford University. Thus, my work has spanned finite element (FEM) simulations on the device scale, equation building and statistics on a mesoscale, and density functional theory (DFT) for atomic modeling. Before the postdoc, I did my PhD on developing fundamental theory and computational methods for CDI at KTH Royal Institute of Technology in Sweden under Prof. Joydeep Dutta.
In CDI, my key achievement has been to develop a new process to achieve up to 100-fold higher ion selectivity with the same electrode materials. The discoveries have been supported by my newly developed software and computational methods, which make it possible to simulate multi-ion selectivity in much more detail than was possible before.
The research work is supported by a repatriation grant from the Knut and Alice Wallenberg Foundation on multi-scale modeling. I have also been awarded a grant from the Åforsk Foundation on sustainable materials for ion extraction with CDI. Thank you!
Research
CDI is an electrochemical method for water purification. It uses a device with two porous electrodes separated by a spacer. A voltage is applied during the operation, which causes salt ions to collect in the porous electrodes. When the electrodes are full, the voltage is removed and the salt ions are discharged. Below is an animation showing the process:
In CDI, electrode materials can be chosen based on the type of contaminants in the water we want to remove. Thus, it can be adopted for desalination, water softening, removing fertilizers, etc. There is also a growing interest in microplastics and medical residues.
The CDI process can be simulated by constructing equations that show how the salt ions move and get adsorbed inside the device during the operations. Thus, the simulation can show how transport, adsorption, and selectivity depend on how the device is used and constructed.
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