The 2024 Archimedes Dinner and Lecture Slideshow
The 2024 Archimedes Dinner and Lecture was held on November 20 at the Italian Academy
A New Paradigm for Desalination
New York, NY—May 6, 2019—Hypersaline brines—water that contains high concentrations of dissolved salts and whose saline levels are higher than ocean water—are a growing environmental concern around the world. Very challenging and costly to treat, they result from water produced during oil and gas production, inland desalination concentrate, landfill leachate (a major problem for municipal solid waste landfills), flue gas desulfurization in fossil-fuel power plants, and effluent from industrial processes.
If hypersaline brines are improperly managed, they can pollute both surface and groundwater resources. But if there were a simple, inexpensive way to desalinate the brines, vast quantities of water would be available for all kinds of uses, from agriculture to industrial applications, and possibly even for human consumption.
A Columbia Engineering team led by Ngai Yin Yip, assistant professor of earth and environmental engineering, reports today that they have developed a radically different desalination approach—“temperature swing solvent extraction (TSSE)”—for hypersaline brines. The study, published online in Environmental Science & Technology Letters, demonstrates that TSSE can desalinate very high-salinity brines, up to seven times the concentration of seawater. This is a good deal more than reverse osmosis, the gold-standard for seawater desalination, and can handle approximately twice the seawater salt concentrations.
Currently, hypersaline brines are desalinated either by membrane (reverse osmosis) or water evaporation (distillation). Each approach has limitations. Reverse osmosis methods are ineffective for high-saline brines because the pressures applied in reverse osmosis scale with the amount of salt: hypersaline brines require prohibitively high pressurizations. Distillation techniques, which evaporate the brine, are very energy-intensive.
Yip has been working on solvent extraction, a separation method widely employed for chemical engineering processes. The relatively inexpensive, simple, and effective separation technique is used in a wide range of industries, including production of fine organic compounds, purification of natural products, and extraction of valuable metal complexes.
“I thought solvent extraction could be a good alternative desalination approach that is radically different from conventional methods because it is membrane-less and not based on evaporative phase-change,” Yip says. “Our results show that TSSE could be a disruptive technology—it’s effective, efficient, scalable, and can be sustainably powered.”
TSSE utilizes a low-polarity solvent with temperature-dependent water solubility for the selective extraction of water over salt from saline feeds. Because it is membrane-less and not based on evaporation of water, it can sidestep the technical constraints that limit the more traditional methods. Importantly, TSSE is powered by low-grade heat (< 70 C) that is inexpensive and sometimes even free. In the study, TSSE removed up to 98.4% of the salt, which is comparable to reverse osmosis, the gold standard for seawater desalination. The findings also demonstrated high water recovery (>50%) for the hypersaline brines, also comparable to current seawater desalination operations. But, unlike TSSE, reverse osmosis cannot handle hypersaline brines.
“We think TSSE will be transformational for the water industry. It can displace the prevailing practice of costly distillation for desalination of high-salinity brines and tackle higher salinities that RO cannot handle,” Yip adds. “This will radically improve the sustainability in the treatment of produced water, inland desalination concentrate, landfill leachate, and other hypersaline streams of emerging importance. We can eliminate the pollution problems from these brines and create cleaner, more useable water for our planet.”
Yip’s TSSE approach has a clear path to commercialization. The heat input can be sustainably supplied by low-grade thermal sources such as industrial waste heat, shallow-well geothermal, and low-concentration solar collectors. He is now working on further refining how TSSE works as a desalination method so that he can engineer further improvements in performance and test it with real-world samples in the field.
Columbia Engineering
Columbia Engineering, based in New York City, is one of the top engineering schools in the U.S. and one of the oldest in the nation. Also known as The Fu Foundation School of Engineering and Applied Science, the School expands knowledge and advances technology through the pioneering research of its more than 220 faculty, while educating undergraduate and graduate students in a collaborative environment to become leaders informed by a firm foundation in engineering. The School’s faculty are at the center of the University’s cross-disciplinary research, contributing to the Data Science Institute, Earth Institute, Zuckerman Mind Brain Behavior Institute, Precision Medicine Initiative, and the Columbia Nano Initiative. Guided by its strategic vision, “Columbia Engineering for Humanity,” the School aims to translate ideas into innovations that foster a sustainable, healthy, secure, connected, and creative humanity.
About the Study
The study is titled “Membrane-less and Non-evaporative Desalination of Hypersaline Brines by Temperature Swing Solvent Extraction.”
Authors are: Chanhee Boo,† Robert K. Winton,† Kelly M. Conway,† and Ngai Yin Yip*,†,‡
† Department of Earth and Environmental Engineering, Columbia Engineering
‡ Columbia Water Center, Columbia University
The authors declare no financial or other conflicts of interest.
“The energy-air-water-food nexus is the existential question of our times,” says Sanat Kumar, the Bykhovsky Professor of Chemical Engineering.
Recognizing the interdependence of the earth’s resources, Kumar believes developing affordable, sustainable energy solutions will be at the heart of increasing access to pure air, clean water, and food security for developing countries.
Advanced membranes will play a key role in this undertaking. For decades, membrane technology has been driving efficiencies in water purification, gas separation for more sustainable energy production systems, and ion separation for energy storage and batteries. Yet, the separation capabilities of standard polymer-based membranes (plastic films) are limited.
Kumar’s research group focuses on developing novel hybrid materials that combine polymers with nanoparticles to gain desired properties and improve separating abilities while reducing plastics consumption. Membranes perform best when the dispersion of nanoparticle fillers is uniform in the polymer matrix. His team has developed a process to chemically bond polymer chains to the fillers in such a way that they self-assemble into regular arrays, exhibiting the evenness needed for better performance.
To date, Kumar has developed materials that perform two to five times better than existing technologies for gas separation and has ideas for further improvements that could translate these methods for commercial use.
In another research thrust, his group seeks to improve the mechanical or electrical properties of polymeric membranes by drawing inspiration from nature, particularly nacre, commonly known as mother-of-pearl. Further advances in this area could lead to more sustainable, composite materials that are durable enough to replace structural materials in buildings and infrastructure.
With the potential for climate change to exacerbate social inequalities, Kumar feels a sense of urgency in bringing about sustainable technologies that will benefit all.
“It is our responsibility, especially as a school dedicated to engineering for humanity, to focus on the poor and provide them with the means to live their lives with dignity.”
The Big Idea - Reimagining the Battery
Conscientious consumers are always on the lookout for ways to limit carbon footprints, whether driving hybrids, installing solar panels or purchasing sustainably-sourced goods. But those results can be a drop in the bucket beside massive systemic emissions—measured in hundreds of billions of tons—stemming from key industrial sectors like construction and big data. Just cleaning up these two fields could be a game changer in the fight against climate change.
Take your home, for instance. Better insulation and more weather stripping are decent ways to increase a building’s efficiency after the fact, but by the time it’s been built tons of carbon emissions have already been baked in: conventional processes for manufacturing cement and steel currently account for 11% of all anthropogenic greenhouse gas emissions, and that’s likely to double by 2050 absent urgent innovation.
Ah-Hyung (Alissa) Park, Lenfest Earth Institute Associate Professor of Climate Change in earth and environmental engineering, as well as an associate professor in chemical engineering and director of the Lenfest Center for Sustainable Energy, is also cofounder of the Columbia startup GreenOre CleanTech. The company utilizes her patented methods for harvesting carbon and valuable chemical products from iron and steel waste known as slag. In addition to deploying their methods in China, where they have a commercial plant in the works, she and her team are also partnering with the state of Wyoming to replace standard cement production with a greener approach recycling ash from power plants into a variety of useful materials.
With cement processing alone generating around five percent of humans’ greenhouse gas emissions, going carbon-neutral would be transformative—but carbon-negative could be revolutionary. Professors Daniel Esposito and Shiho Kawashima are working on a new cement alternative that could help lay the foundation for a greener urban landscape. Synthesized from seawater, their material can withstand as much weight as the industry standard while absorbing substantial amounts of CO2. They’re currently translating their research into scalable production processes for future construction.
“We’re getting promising results in the lab, so we plan to do lifecycle analysis and techno-economic analysis to demonstrate our technology’s environmental benefits and economic viability,” Kawashima says.
While less conspicuous, data infrastructure is on pace to become another enormous source of emissions. Moving, storing, and particularly processing the trillions of gigabytes so effortlessly at our fingertips requires a vast amount of energy. If present trends continue, the information economy could soon produce half as many greenhouse gases as the entire transportation sector, with cloud computing consuming a fifth of the world’s electricity. As is, data centers already cause nearly two percent of our total carbon output—and that’s while we’re still at the dawn of artificial intelligence. Training algorithms require gigawatts of power, and the energy costs of rapidly proliferating AI could be staggering.
That’s partially because our wireless lifestyles actually rely on a vast tangle of inefficient electronic wiring, fundamentally the same materials we’ve been using since the 1940s. Professors Keren Bergman and Michal Lipson, however, are reconceiving the mechanics of computation using a whole new framework: frictionless optical components. Fiberoptics already use this principle to transfer data over long distances—but such bulky systems have proved incompatible with today’s data centers. Lipson and Bergman’s “photonic” elements neatly sidestep that issue by encoding data in the form of light directly on the chip.
Lipson’s group recently had a breakthrough pairing an optical funnel with optical fiber to achieve highly efficient high-bandwidth transmissions even when components weren’t in perfect alignment, while Bergman’s group in the Lightwave Research Laboratory just won a $4.8 million DARPA grant to develop efficient optical interconnects for feeding high-bandwidth signals from chips to anywhere in a computing system. Such advances could one day soon allow artificial intelligence to reach unlimited potential without consuming unreasonable amounts of energy.
