Scientists in Florida that are concerned by the global accumulation of waste are working on a novel material to replace plastic across a broad range of applications. In the process, they've created a "CO2 sponge"—a wood-based polymer that can capture and release carbon dioxide on demand without the need for extreme pressure or temperatures. The reusable material could offer a solution to jam-packed landfills and to unchecked carbon emissions, which are perpetuating global climate change and shrinking Earth's upper atmosphere.
Chemical engineers at Florida A&M University and Florida State University shared that their material largely consists of lignin, a biopolymer that lends structure and resilience to wood and other plant fibers. The team (members of whom work together via the FAMU-FSU College of Engineering) collaborated earlier this year to create an alternative to petroleum-based plastics, which are often used for short lifespan products despite their lengthy biodegradation times.
Their lignin-based material—known officially as a biomass-based polymer—isn't just built from a renewable resource; it's also endlessly recyclable, as it can be degraded via depolymerization and then used to create the same material again. Left unrecycled, lignin breaks down faster than plastic, albeit at a slower rate than other organic materials.
Over the past few months, the team has found that their material could help the planet in another way: by capturing carbon dioxide. A recent paper for Advanced Materials reveals that by placing the biomass-based polymer under alkaline conditions at room temperature and ambient pressure, the scientists can effectively command the material to absorb carbon dioxide. When placed in a concentrated carbon dioxide source, each gram of material captures 47 milligrams of carbon; under everyday conditions, one gram of material captures 26 milligrams of carbon. Releasing the carbon only requires heating the material to 60 degrees Celsius, or 140 degrees Fahrenheit.
"This is like a sponge for CO2," chemical and biomedical engineering professor Hoyong Chung said in FSU's statement. "It’s fascinating to see what is possible with this material."
Chung and his colleagues hope their material will eventually offer a versatile alternative to non-renewable manufacturing substances that take centuries to break down and don't have any carbon sequestering abilities. Depending on a manufacturer's need, the biomass-based polymer could be used to create recyclable products designed to have short lifespans—like packaging and disposable cutlery—or to build mid-term items that absorb atmospheric carbon.
At this time, it doesn't appear Chung's team's material is ideal for larger, load-bearing structures, though another wood-based substance unveiled last year by Rice University could fill that gap.
Capturing CO2 From the Air
Researchers from Florida State University have created a novel biomass-based material that can continuously absorb and release carbon dioxide (CO2). The material's major constituent, lignin, is an organic molecule found in wood and other plants. It can absorb CO2 straight from the air or from concentrated sources. This research was published in the journal Advanced Materials.
Controlling CO2 Release
The beauty of this work is the ability to precisely control the capture and release of CO2 without high pressure or extreme temperatures. Our testing showed that this material’s structure stayed the same even after being used multiple times, making this a promising tool for mitigating carbon emissions.
The Material's Potential
Chung's group previously developed a polymer made from lignin and CO2, providing a sustainable alternative to conventional petroleum-based plastics. This new work builds on that research by demonstrating the potential to reverse the process and recycle the material for future CO2 absorption.
Lignin's Role in the Material
Lignin, an abundant and inexpensive byproduct of wood processing, is a natural resource researchers are exploring for innovative uses. In this study, one gram of the material developed by Chung's team captured about 47 mg of CO2 from a concentrated source and 26 mg from ambient air, equating to roughly 5% of the original material's weight. The absorbed CO2 can either be released for use in various industrial and agricultural processes or stored permanently.
Understanding the Release Mechanism
The researchers were surprised by the mechanism for releasing CO2. During nuclear magnetic resonance spectroscopy analysis, they observed bubbles forming as the material was heated, indicating an unexpected release of CO2.
That sparked our curiosity: What is going on here? Why do we see these little bubbles every time we try to analyze this polymer?
Further analysis revealed that the material was releasing CO2 in response to heat. Upon investigating the reaction, the researchers found that they could control the amount of CO2 emitted by adjusting the temperature applied to the sample. They also demonstrated that the released CO2 could be utilized in other chemical reactions.
Efficiency of the Reuse Process
The reuse process is efficient, as high temperatures and pressures are not necessary; CO2 can be released at temperatures as low as 60 °C under standard atmospheric pressure. Additionally, the CO2 release temperature can be adjusted—either increased or decreased—depending on the intended application.
A Sponge for CO2
This is like a sponge for CO2, absorbing it, releasing it, and drying up so it can capture more. It is fascinating to see what is possible with this material.
The Future of the Material
The Lead Author of the study was Postdoctoral Researcher Arijit Ghorai.
The US Department of Agriculture National Institute of Food and Agriculture supported this work.
This new material, a "CO2 sponge," could revolutionize how we think about plastic and its environmental impact. This breakthrough in material science could contribute to a true circular economy, where materials are endlessly reused and recycled. While it's still early days for this technology, the potential to replace plastic and fight climate change is truly exciting.
