As global waterways face increasing threats from algae blooms and pollution caused by agricultural runoff and industrial waste, innovative solutions are urgently needed to address contaminants such as phosphate, copper, and zinc. Researchers at Northwestern University have developed a groundbreaking, reusable sponge technology that not only captures these pollutants but also enables their recovery for potential reuse, offering a sustainable and cost-effective alternative to traditional methods.
Published in ACS ES&T Water, the study outlines a versatile platform that can be tailored to target specific pollutants, such as those impacting Chicago’s waterways. The sponge, coated with nanoparticles designed to attract and retain contaminants, has demonstrated success in capturing metals like zinc and copper, as well as phosphate. Previous iterations of the technology have also effectively removed lead, microplastics, and oil from water systems. By adjusting the pH levels, the sponge releases the captured resources, allowing them to be repurposed rather than discarded.
Led by Vinayak Dravid, Abraham Harris Professor of Materials Science and Engineering at Northwestern’s McCormick School of Engineering, the research team has created a highly adaptable solution. “This technology can function as a universal sorbent or be customized to target specific contaminants, such as metals, plastics, or nutrients,” explained Dravid, who also serves as the founding director of the NUANCE Center and the SHyNE Resource, and associate director for global programs at the International Institute of Nanotechnology.
How the Sponge Works
The sponge platform, initially developed using polyurethane, has evolved into a hydrophilic cellulose-based material coated with pollutant-specific nanoparticles. Its porous structure provides a high surface area, enabling efficient pollutant capture. Dravid likens the technology to a “Swiss Army knife” due to its versatility and reusability. To commercialize the innovation, Dravid founded Coral Innovations (formerly MFNS-Tech), a startup focused on environmental remediation.
Targeting Specific Pollutants
The research gained momentum when StormTrap, LLC, a stormwater treatment equipment manufacturer, approached the team to address three key pollutants affecting Chicago. StormTrap sought to integrate absorbent materials into their product line and challenged the researchers to reduce pollutant concentrations to untraceable levels. Current Environmental Protection Agency (EPA) standards for mineral concentrations in drinking water often exceed environmentally safe thresholds, particularly for preventing algae blooms and other ecological impacts.
Kelly Matuszewski, a Ph.D. student in Dravid’s group and the paper’s first author, spearheaded the development of a method to recover captured resources. By manipulating pH levels, Matuszewski successfully flushed out metals like copper and zinc, followed by phosphate, achieving water with undetectable pollutant levels. Remarkably, the sponge maintained its effectiveness even after five cycles of use.
From Lab to Real-World Applications
The collaboration with StormTrap has accelerated the transition from laboratory testing to real-world implementation. While initial experiments were conducted in controlled environments with uniform pollutant concentrations, the next phase will involve field testing to determine the sponge’s capacity and durability in diverse conditions. This step is critical for scaling the technology and partnering with other researchers to advance cleaner waterway initiatives.
Matuszewski, a finalist in Northwestern’s FoundHer Spotlight competition for early-career women scientists, will present her work on March 5, highlighting the potential of this innovation to address pressing environmental challenges.
A Sustainable Future for Water Remediation
As global reserves of phosphate and metals dwindle, the ability to recover and reuse these resources is becoming increasingly vital. “We can’t afford to keep flushing these minerals away,” Matuszewski emphasized. “Understanding their interactions and finding ways to repurpose them is essential for a sustainable future.”
This pioneering sponge technology represents a significant step forward in environmental remediation, offering a scalable, reusable, and cost-effective solution to combat water pollution while promoting resource recovery.
