Membraneless Seawater Desalination with a Bipolar Electrode

Physical Sciences : Electrical

Available for non-exclusive licensing

Inventors

  • Richard Crooks, Ph.D. , Chemistry and Biochemistry
  • Kyle Knust, Ph.D. , Chemistry and Biochemistry
  • Robbyn Anand, Ph.D. , Chemistry and Biochemistry

Background/unmet need

Note: this technology is presently the subject of Technology Transfer Opportunity (TTO) in the U.S. Department of Energy SBIR/STTR Program FY 2018 Phase I Release 1, as Topic 21a. (https://science.energy.gov/sbir/funding-opportunities/) Until no earlier than January 8, 2018, it is available for licensing solely through that program.

The global demand for fresh water continues to grow with population expansion. Many conventional sources of potable water, including lakes, rivers, and aquifers, are becoming stressed and even depleted during certain times due to temporary droughts. The United Nations estimates two-thirds of the global population could be living in water-stressed regions by the year 2025.

Approximately 97% of all the water on the planet is seawater, high in salt content. Desalination, the process of removing salt and creating fresh water, offers the potential to provide endless supply of drinkable water for all human populations. Unfortunately, existing desalination processes are very energy-intensive, as high-pressure, multi-stage pumps are required to generate adequate pressure to force seawater through reverse osmosis membranes with extremely small pores capable of diverting dissolved salts away from the fresh water. The capital cost of typical desalination systems prevents their widespread use, particularly in developing countries, where some of the most water-stressed populations exist.

Invention Description

Researchers at The University of Texas at Austin have developed a novel, membraneless desalination process utilizing microfluidics to channel high salinity water to a microelectrode positioned at the intersection of the inlet channel and two outlet channels. Under an applied voltage, and in the presence of a flow of saltwater, the microelectrode generates an electric field gradient, which preferentially directs ions in the saltwater into one channel, while the desalted water flows to the other. The concept, called electrochemically mediated desalination (EMD), can be scaled and made massively parallel through standard integrated-circuit manufacturing techniques to generate large, stackable arrays that would be able to generate meaningful volumes of fresh water from high-salinity feed, using relatively low amounts of electrical energy.

In the publications linked below, the researchers have presented data from single cells operating under one set of conditions: 25% salt rejection, 50% recovery, 40 nL/min per cell, and 0.025 kWh/m3. It will be necessary provide parallel arrays of many small cells in order to build devices that can generate useful amounts of water. What is particularly promising is the low energy requirement of this new approach, and the absence of a membrane.

http://rcrooks.cm.utexas.edu/research/resources/Publications/rmc246.pdf

Benefits/Advantages

  • Dramatic reduction in energy requirement for desalination
  • Energy efficiency approaching the theoretical minimum
  • Scalable through modular design to meet specific volume requirements
  • No membranes required, meaning reduced capital cost and elimination of maintenance costs
  • Minimal pretreatment required compared to reverse osmosis or electrodialysis

Features

  • Modular design allows for flexibility in system size and throughput.
  • Low energy consumption allows for use in developing countries.
  • Low voltage requirement will integrate well with renewable energy sources.

Market potential/applications

BCC Research reports that global cumulative investments in desalination plants reached roughly $21.4B in 2015 and is expected to surpass $48B by 2020.

IP Status

  • 1 foreign patent application filed
  • 1 foreign patent issued
  • 1 U.S. patent application filed
  • 1 U.S. patent issued: 9,932,251

Web Links

FAQ

You may submit questions to licensing@otc.utexas.edu, and answers will be posted here. Advisory: this is a public FAQ, and the purpose of the FAQ is to provide an open exchange of technology, technical data, or other information.

Q1. What progress has been made since the patent was filed a few years ago?

Fundamental research is ongoing in the laboratory of Professor Crooks to understand and optimize faradaic ion concentration polarization and its applications. These investigations remain at the single-cell scale. As new research is published, an updated list of publications is maintained at http://rcrooks.cm.utexas.edu/research/styled-2/index.html.

Q2. Is it correct that you have a working model of a single channel device? Would the goal during a potential SBIR or STTR be to fabricate and evaluate a multi-channel device?

Yes, the researchers have presented data from single cells operating under one set of conditions: 25% salt rejection, 50% recovery, 40 nL/min per cell, and 0.025 kWh/m3. While the goals of any particular proposal are up to its authors, in order to build devices that can generate useful amounts of water, we believe it is likely to be necessary to provide parallel arrays of many small cells.

Q3. Is this available for exclusive licensing?

Yes, but presently only through the DOE SBIR/STTR FY 2018 Phase I program. A sample option agreement, such as may be put in place with DOE’s awardee for this TTO (if there is one), is available above (see “Web Links” above).

Q4. Have there been previous efforts to commercialize this technology?

Yes.

Q5. Has anyone entered into a license agreement?

There was a previous licensee, however that license has ended.

Q6. What problems have been encountered in any scaled-up devices?

We can’t comment on any specific research or results of a previous licensee. We have identified that parallelization, electrode lifetime, and manufacturability are some key challenges in scaling up this technology.

Q7. Chloride oxidation can be corrosive to electrode materials. Are there problems with electrode degradation?

Yes. The original research used pyrolyzed photoresist carbon (PPC) electrodes, which can corrode. Other suitable conductive materials on and/or within substrate materials can be patterned to fabricate electrodes using methods known in the art.

Q8. Is it possible to collaborate with UT Austin on an SBIR/STTR award?

Collaboration is a possibility. Although a maximum of one proposal would be awarded by DOE, UT Austin might participate in the statements of work for multiple Phase I proposals.

Q9. Should we start out with a nondisclosure agreement (NDA)?

If you would like to discuss specific plans for a potential collaboration, and need to disclose confidential information to do so, please review our NDA template, fill out the information on page 1, and return it to us. We will review and finalize the NDA and return it to you for signature.