CDI

At TU Delft, there is currently an opening for a 2-year postdoc to work in the field of capacitive deionization (CDI) in close collaboration with Avsalt AB, a Swedish startup company in this field.

This project is aimed at developing new strategies to induce ion-selectivity in flow-by CDI devices with multiple flow channels (mCDI). Specifically, we will look at ways to tailor the electrode properties at the microscopic level such to induce strong ion-specific transport through the material, with the ultimate goals of selectively removing specific ions from waste-water streams. These goals will be achieved through experiments, combined with molecular dynamics simulations to develop a molecular-level understanding of ion-specific adsorption and diffusion in porous electrodes.

The ideal candidate has experience with experimental CDI, battery, or supercapacitor research, and has hands-on knowledge of molecular dynamics simulations.

Interested candidates can contact Remco Hartkamp (r.m.hartkamp@tudelft.nl)Burak Eral (h.b.eral@tudelft.nl) and Niels Boon (nb@avsalt.com) and send along their CV. The position will be filled as soon as a suitable candidate is found.

SO RESPOND ASAP IF YOU ARE INTERESTED !

The pre-release of the book 'Physics of Electrochemical Processes' (ISBN: 9789090332581) by P.M. Biesheuvel and J.E. Dykstra can now be downloaded from the website www.physicsofelectrochemicalprocesses.com free of charge.

Topics include:

  • Ch. 1: The extended Frumkin isotherm describes the capacitive salt adsorption in intercalation materials
  • Ch. 2: The Donnan model for the electrical double layer structure in charged materials, including electrodes
  • Ch. 3: The Gouy-Chapman-Stern model and surface ionization
  • Ch. 4: Volume effects in EDL theory (Bikerman, Carnahan-Starling, activity coefficients)
  • Ch. 5: Heat effects for current flow across the EDL (Peltier effect, electrostatic cooling)
  • Ch. 6: EDLs in motion: electrowetting, contact angle, energy harvesting
  • Ch. 7: EDL interaction (DLVW theory)
  • Ch. 8: Transport phenomena (mass transfer to interfaces including dispersion) (in preparation)
  • Ch. 9: Electrokinetics (hydrostatic and osmotic pressure, Navier-Stokes equation for electrolytes, osmosis vs electro-osmosis) (in preparation)
  • Ch. 10: Acid-base reactions in transport models
  • Preamble: The microscopic and experimental perspective of the electrical double layer
  • Ch. 11: The difference between capacitive (non-Faradaic) and Faradaic electrode processes in electrochemistry
  • Ch. 12: Electrode kinetics (in preparation)
  • Ch. 13: Porous electrodes (in preparation)
  • Ch. 14: Reverse Osmosis
  • Ch. 15: Electrodialysis
  • Ch. 16: Ion transport in bio-electrochemical systems
  • Ch. 17: Bioelectrochemical conversions on conductive media
  • Ch. 18: Overview of electrochemical water desalination (in preparation)
  • Ch. 19: Numerical methods (2021)
  • Ch. 20: Analysis of experimental methods in electrochemistry (2021)

A new open access paper was recently published in Desalination that compares the energy use of RO and CDI.

Porada et al. “Energy consumption in membrane capacitive deionization and comparison with reverse osmosis”, Desalination (2020), https://doi.org/10.1016/j.desal.2020.114383. 

According to the authors, "the work presents the first fair energy consumption comparison of desalination with MCDI and RO. The comparison is based on experimental data, and the data is compared with results from state-of-the-art theoretical models. We find that the energy consumption difference between RO and CDI is much less than recently reported by the group of Prof. Elimelech (Yale, USA), see weblink."

The authors emphasize that two technologies can only be compared when all metrics are used in the same uniform way, and when for each technology state-of-the-art is considered. A new operational mode for CDI is introduced with a long "hold time" during salt release, leading to unprecedented high values of water recovery obtained in CDI with high feed water salinity of 40 mM NaCl solution. 

 

A new Open Access paper was published in the prestigious journal ES&T, from the group of prof. Meny Elimelech (Yale, USA) which discusses a detailed comparison between electrodialysis (ED) and membrane capacitive deionization (MCDI).

Patel et al. "Energy Efficiency of Electro-Driven Brackish Water Desalination: Electrodialysis Significantly Outperforms Membrane Capacitive Deionization", ES&T (2020). https://pubs.acs.org/doi/abs/10.1021/acs.est.9b07482

According to the authors, "we provide the first systematic and rigorous comparison of the energetic performance of electrodialysis (ED) and membrane capacitive deionization (MCDI) over a broad range of brackish water desalination conditions."

The authors find that:

  • The energy consumption of ED is substantially lower than MCDI for all investigated conditions, with the energy efficiency being nearly an order of magnitude higher for many separations.
  • Even with idealized operation (complete energy recovery and reduction in energetic losses), the energy efficiency of MCDI remains lower than ED.

Finally, the authors emphasize that "for low feedwater salinities (< ~2 g/L), energy efficiency should be a secondary consideration in the choice of desalination technology, with capital cost, ease and reliability of operation, and additionally required treatment steps taking higher priority."

... and the field of Capacitive Deionization keeps on growing at an increasing speed ! With over 160 scientific papers written and published last year, the total number of CDI publications has grown from ∼25 in 2000, to ∼65 in 2010, to over 1,000 at the end of 2019! CDI papers in 2019 came from many prestigious places including Tsinghua University, Seoul National University, Technion, MIT, Stanford, and Yale. This output from such eminent research groups shows that CDI is taking a leading role in the scientific study of water desalination technologies. Analyzing these publication data for the past decade, an exponential growth can be observed, with a doubling of the publication output every 2.5 year !

Citations to the CDI literature have grown from a number less than 100 per year before 2010, to about 2000 per year at the end of 2015, and close to 10,000 per year in 2019. These statistics also reflect an exponential growth, with a doubling time of 2.0 year. This difference in doubling time (faster for citations than publications) may indicate that CDI papers are more and more cited in papers from outside the CDI-field.

We are honored to introduce the 5th International conference on capacitive deionization and electrosorption, which will take place in Atlanta, GA, United States on May 11th-14th, 2021.  The conference will be a good forum for CDI researchers to present new results, draw inspiration, and direct future growth into CDI&E research. We would be grateful for your attendance and participation in this event. To stay up to date with conference preparations, please see our conference website (https://www.cdie2021.com/) or follow us on Twitter (@CDIe_2021).

 

Last week’s conference in Beijing was a great success! 200 scientists met in Beijing and discussed the latest scientific and industrial developments in the field of Capacitive Deionization. The 4-day conference started on Monday with three tutorials on theory, cell architectures and metrics by renowned professors. Thereafter, the scientific part of the program started, with many talks on operation, materials design, ion selective removal & recovery and the industrial application of CDI technology. The conference was hosted by Prof. Peng Liang from the School of Environment of Tsinghua University, and due to his tremendous efforts and the excellent support by his students, all scientists and industrial partners had an amazing week in Beijing!

We are honored to introduce the 4th International conference on Capacitive Deionization and Electrosorption, which will take place in Beijing, China, from May 20 to 23, 2019. The conference will be a good forum for CDI researchers to present the latest results, to draw inspiration and ideas, and to probe into the future development of CDI&E technologies. Twenty eight renowned scientists have confirmed as keynote or invited speaker. Moreover, more than 100 abstracts have already been submitted. Please visit our website for detailed information: http://cdi-e2019.csp.escience.cn/dct/page/70006.

You can still submit an abstract for an oral and/or poster presentation. The deadline for submission has been extended to November 30th, 2018.

Also, early registration is open from November 1st, 2018 to February 28th, 2019. More information related to the conference will be posted on the website soon.

Following the CDI conference recently held in the Republic of Korea, July 2017, twenty scientists active in the field of CDI worked on a joint position paper, putting forward the proposition that CDI defines a class of desalination technologies that share common operational principles and relevant metrics, thereby joining under one common term different CDI cell layouts and chemistries. Thus, according to the position paper, the class of CDI includes electrodes based on carbon materials, but as well electrodes with ion storage based on different chemistries such as using redox materials. The position paper can be downloaded via the link given below.

P.M. Biesheuvel, M.Z. Bazant, R.D. Cusick, T.A. Hatton, K.B. Hatzell, M.C. Hatzell, P. Liang, S. Lin, S. Porada, J.G. Santiago, K.C. Smith, M. Stadermann, X. Su, X. Sun, T.D. Waite, A. van der Wal, J. Yoon, R. Zhao, L. Zou, and M.E. Suss, "Capacitive Deionization -- defining a class of desalination technologies," ArXiv:1709.05925 (2017).