Chemists have introduced a novel porous material that is cost-effective and environmentally friendly.
Gas separation plays a crucial role in various industries, whether it involves extracting nitrogen and oxygen for medical purposes or capturing carbon dioxide during industrial processes or gas purification.
Separating gases can be a laborious and expensive process. Wei Zhang, a chemistry professor at the University of Colorado Boulder, highlights the challenges involved in traditional methods such as cooling air to extremely low temperatures to liquefy gases like oxygen and nitrogen, making the process energy-intensive and costly.
Typically, gas separation relies on porous materials that allow gases to pass through and get separated. However, existing porous materials are usually designed for specific gases, limiting their versatility.
Published in the journal Science, a recent study by Zhang and his team reveals a new type of flexible porous material that can accommodate and separate a wide range of gases. This material, crafted from common resources, combines both rigidity and flexibility to facilitate gas separation with significantly reduced energy consumption, aiming for scalability and sustainability.
Enhancing Flexibility
Traditionally, gas separation materials have been rigid and tailored for specific gases based on their affinity. These rigid materials defined the pores effectively for gas separation but restricted the diversity of gases passing through due to varying molecular sizes.
In their research, Zhang and his team innovated a porous material with a flexible element in the linking node of an otherwise rigid structure. This flexibility enables the molecular linkers to oscillate, altering the pore size and accommodating multiple gases.
Zhang explains, “At room temperature, the flexible linker remains stable, allowing most gases to enter. As we raise the temperature, the oscillation of the linker increases, shrinking the pore size and preventing larger gases from penetrating. Ultimately, only the smallest gas, hydrogen, can pass through at higher temperatures.”
The newly developed material resembles zeolite, a crystalline porous material often composed of silicon, aluminum, and oxygen. With highly ordered pores akin to a honeycomb structure, the material features self-correcting characteristics due to a boron-oxygen bond mechanism employed in its design.
By leveraging dynamic covalent chemistry focusing on the reversibility of boron-oxygen bonds, the researchers achieved a structurally ordered framework that demonstrates tunability and adaptability.
Sustainable Approaches
While developing the porous material posed challenges in understanding its structure initially, the team ultimately achieved a breakthrough. They emphasized scalability in the material’s development to cater to potential industrial applications on a large scale.
The researchers have filed a patent for the material and are exploring further avenues by experimenting with different building block materials. Zhang envisions collaboration with engineering experts to incorporate the material into membrane-based solutions, which could offer more sustainable alternatives in the long run.
Zhang emphasizes, “Our aim is to advance technology to meet industrial demands sustainably. Membrane-based separations hold promise for reduced energy consumption and could offer more environmentally friendly solutions.”
