Researchers at Rice University have developed an innovative synthesis strategy that could revolutionize the way we tackle environmental challenges, including the decontamination of ‘forever chemicals’ or per- and polyfluoroalkyl substances (PFAS). By creating a continuous production system for covalent organic frameworks (COFs), a class of porous materials with immense potential, the team has paved the way for faster, more cost-effective, and higher-quality COF production. This breakthrough could accelerate the development of cleaner and more efficient technologies for contaminant removal, according to the researchers. As the world grapples with the persistence and health risks of PFAS, this new synthesis strategy offers a glimmer of hope in the fight against these ‘forever chemicals’.
Realizing COFs’ Potential
Covalent organic frameworks (COFs) belong to this new class of materials that combine both crystallinity and ordered nanostructuring alongside porous molecular-level order, which confers on them interesting properties such as high porosity, large surface area, and low thermal conductivity… these properties originated from their tunable molecular structure. This makes them an ideal raw material for use in a variety of applications that span the gamut from semiconductors and sensors to drug delivery and filtration.
Nonetheless, producing COFs is slow and costly which presents challenges to their widespread use. Enter the Rice University researchers. With this new synthesis strategy, they were able to synthesize COFs at a much quicker rate but are also of higher quality and greater versatility.
Their breakthrough is based on their development of a multi flow microreactor, enabling the continuous synthesis and processing of multiple COF chemistries. This “mini factory on a lab bench” approach is the opposite of making all the cookies at once in one big batch. The researchers can perform high-quality COFs with higher crystallinity by finely tuning the temperature and mixing at every step.
PFAS Sustainable Remediation
In addition to its wide-ranging applications, where this new COF synthesis strategy is especially impactful is in dealing with a significant problem that has been plaguing us: PFAS contamination. PFAS, or per- and polyfluoroalkyl substances, are a class of “forever chemicals” that persist in the environment for thousands of years and have been associated with numerous adverse health effects including cancer and reproductive harm.
The work conducted by the researchers has also demonstrated that one of the COFs created using their flow synthesis technique is especially adept at degrading the perfluorooctanoic acid (PFOA), a well-known PFAS compound. This photocatalytic degradation process is a light-activated route operating at room temperature, and thus enables a significantly more efficient and green alternative when compared to conventional PFAS remediation methods.
‘In Pictures: Building Arctic COFs These COFs are akin to powerful sponges with built-in ‘sunlight engines’ that can degrade toxic molecules up to two times more efficient compared to the best reported photocatalysts today,’ said Safiya Khalil, lead author of the study. One of the COFs we built was three or four orders of magnitude superior to decomposition of PFOA relative to conventional TiO2 photocatalysts, a popular this material in pollution control applications.
To a Clean and Sustainable Future.
The significance of this new COF synthesis methodology extends further than just PFAS decontamination. A faster and less costly way to make high-performance COFs would enable a host of applications that benefit the environment and a cleaner, sustainable future.
Covalent organic frameworks have applications that could potentially tackle some major environmental issues such as energy storage and pollution control. The work by the Rice University team promises to help move COFs out of mere curiosity items and into everyday use by speeding up the search for new formulations and their inclusion in future technologies through easier-to-produce quantities.
‘By using this approach, we wish to provide a platform to enable the large-scale production of COFs, and in turn fast-track future formulation development,’ Khalil added. That this process is quicker and consumes less energy with higher quality of the end product.
With the world increasingly facing the menace of environmental pollution on larger and scarier proportions, this success in COF synthesis can possibly be a game-changer in making our world greener and unsustainable. The paths to new innovations are clear from the sloughed graphene extracted by the ionic liquid/Ring-opening metathesis polymerization researchers at Rice, and demonstrate that great advances in the lab come ironically enough not from thinking outside of boxes but instead focusing on how gritty solutions can solve hairy problems.
