Research Highlight

After 2 years of postponed, canceled, or remote scientific interactions, the NAWI research community has been well represented at summer water research conferences.  These conferences have been venues for sharing the results of NAWI’s early R&D accomplishments (roadmaps, baselines, WaterTAP, WaterDAMS, research outputs, etc.) and an opportunity to take stock of NAWI’s influence on the water desalination field more broadly.  Below are several highlights from NAWI Research Consortium and Alliance members who attended the conferences and noted the degree to which NAWI’s research agenda has influenced the direction of water treatment across the broader research community.  

NAMS 2022: Phoenix, AZ

Profs. Manish Kumar of UT Austin (a NAWI project performer and Beamline Characterization Advisory Council member) and Mary-Laura Lind of ASU hosted the North American Membrane Society annual meeting in Phoenix, AZ.  A hybrid remote and in-person conference, this well attended set of workshops and conferences offered the first opportunity for the membrane community to come together after release of our roadmapping and baselining products.  Manish mentioned that “NAWI roadmaps and NAWI supported research has shifted the conversation in the membrane community (as seen in NAMS meetings) and in the environmental engineering community more broadly towards electrification of water treatment and a focus on resource recovery in a significant way. Interest in oxyanion pollutant treatment has also grown as a result of NAWI activities as seen in presentations on these topics.”

AEESP 2022: Washington University in St. Louis

Prof. Dan Giammar of WUSTL (a NAWI Cartographer) was the co-chair of the AEESP conference held on the beautiful WUSTL campus.  The agenda focused on convergence research, highlighting (among other topics) ways in which research, practice, and entrepreneurship were critical to addressing issues in water, climate, and sustainability. Dan noted that “a substantial number of the 320 abstracts submitted to the 2022 AEESP Research and Education Conference were focused on advanced water treatment processes.  When our program committee had to determine an effective way for thematically grouping the presentations, the best framework that emerged was based on A-PRIME.  Electrified treatment processes, modular membrane systems, and precision separations were all highlighted in the conference program.”

Other highlights included NAWI Next-Gen Katie Weitzel winning the best poster award at AEESP for her research on “Treatment and Reuse of Agricultural Drainage Water: Challenges and Opportunities” and Dr. Tim Bartholomew, Dr. Dan Gunter, Prof. Daniel Gingerich and myself hosting a pre-conference workshop with 90+ registrants on NAWI’s WaterTAP and WaterDAMS tools. (All materials are available here, for those of you unable to make the workshop, but are interested in learning more!) The highlight of the conference for me was seeing Amy Childress’ (a NAWI Cartographer) group at USC present on their cooling water treatment baseline analysis using NAWI’s WaterTAP tools.  

GRC in Membranes: Materials and Processes

NAWI Deputy Topic Area Lead Jeff McCutcheon and several NAWI research consortium and Alliance members are attending the GRC in Membranes: Materials and Processes as you read this dispatch. Having seen a preview of the invited speakers, Jeff anticipates tremendous interest and lively discussion around Daniel Miller’s (LBNL) presentation of his NAWI-funded project on Computational and Experimental Test Beds for Prediction of RO Module Fouling.  Jeff also noted that “NAWI has had a big impact on the membrane science community, particularly by highlighting the critical need for innovation in brine management as a key opportunity to lower the cost and energy use for desalination in the United States.”

Several other upcoming conferences will afford additional opportunities for NAWI to disseminate research results and share our collective vision for accessing non-traditional water at pipe parity through innovations in A-PRIME. We also look forward to hearing about innovations in the field, successes that change the R&D landscape in one or more A-PRIME areas, or new research directions that NAWI should consider allocating funding toward. 

An article called Salt and Water Transport in Reverse Osmosis Membranes: Beyond the Solution-Diffusion Model was published in the December issue of Environmental Science and Technology (Environ. Sci. Technol. 2021, 55, 16665−16675). The publication is authored by researchers at Yale University in the U.S. and Wageningen University and WETSUS in the Netherlands, including Li Wang, Tianchi Cao, Jouke E. Dykstra, Slawomir Porada, P. M. Biesheuvel, and Menachem Elimelech.

This article, along with a companion publication in the Journal of Membrane Science by the same three institutions, describes an important breakthrough in how to more accurately model water and salt transport in thin film composite membranes. The Water Desalination Report, the leading industry trade communication on desalination, devoted an entire page to summarizing the findings outlined in the article.

We spoke with Professor Menachem Elimelech, Sterling Professor of Chemical and Environmental Engineering at Yale University, about the research. “Basically, I had been irritated for a long time,” he explains. “The solution-diffusion model treats membranes as a black box…dissolving and diffusing without considering the unique chemistry and pathways [for transport through real membranes]. What bothered me even more: it hinders development of water and solute transport improvements. For example, why do some membranes reject boron well and not others?” 

To address the limitations of the long-standing solution-diffusion model, Elimelech and his collaborators formulated a new “solution-friction” model in which “ion transport through the membrane is described by the extended Nernst−Planck equation, with the consideration of friction between the species (i.e., ion, water, and membrane matrix). Water flow through the membrane is governed by the hydraulic pressure gradient and the friction between the water and membrane matrix as well as the friction between water and ions.” The model does an excellent job of matching experimental results using only 2 fitting parameters. Read the journal article Salt and Water Transport in Reverse Osmosis Membranes: Beyond the Solution-Diffusion Model.

This publication covers topics such as: 

• Open-access database of reverse osmosis membrane performance and characterization data.
• User-sourcing for transparent sharing of experimental results.
• Dynamic environment for membrane comparisons and analyses under uniform reporting conditions.
• Optimal platform for developing databases for other commonly used membrane separation technologies.

Read the full publication.

Published in PNAS, September 14, 2021. Access the publication. 

Researchers lack the tools for quantitatively evaluating the impact of their research on technology costs, especially when those technologies comprise multiple components or when the component costs are highly uncertain. We propose a suite of tools to aid in evaluating technology platforms, setting system- and component-level research targets and identifying high-impact innovation trajectories. These tools are applicable to any technology composed of multiple components whose performance or cost will benefit from innovation, but they are especially valuable for membrane systems in which the high interdependence in components amplifies or dampens the effects of innovation in nonintuitive ways.

Lead author Jason Yang from NAWI Consortium Member Yale University discusses the results of molecular dynamics simulations examining the removal of small organic contaminants in water with nanoporous graphene membranes. Read about this research.