Fish Waste Benefit Uses Synthesis Process to Turn Then Useless Material Into Carbon-Based Nanomaterial

Because of the low toxicity and chemical stability, not to mention exceptional optical properties, carbon-based nanomaterials are finding more and more applications across storage, energy conversion, biomedicine, and catalysis.

Carbo nano-onions or CNOs are definitely no exception, a Phys.org report specified. First reported in 1980, CNOs are nanostructures comprising concentric shells of fullerenes that resemble "cages within cages."

More so, they offer attractive qualities like high surface area and large electrical and thermal conductivities.

Regrettably, the conventional approaches for generating CNOs have some serious drawbacks. Some necessitate harsh synthesis conditions like high temperatures or vacuum, while others demand a lot of time and energy.

High-Quality CNOs

Some strategies can avoid limitations but call for complicated catalysts, costly carbon sources, or dangerous acidic or basic conditions. This is greatly limiting the potential of CNOs.

Fortunately, not all hope is missed. In recent research published in the Green Chemistry journal, a team of researchers from Nagoya Institute of Technology in Japan found a simple and convenient way of turning fish waste into extremely high-quality CNOs.

The team, including Assistant Professor Yunzi Xin, Master's student Kai Odachi, and Associate Professor Takashi Shirai, created a synthesis route in which fish scales removed from fish waste after cleaning are turned into CNOs in mere seconds through microwave pyrolysis.

However, how fish scales are easily converted into CNOs remains a question. While the exact reason is unclear, the researchers believe it is due to the collagen found in fish scales, which can absorb adequate microwave radiation to produce a rapidly rising temperature.

'Pyrolysis' Thermal Decomposition

The procedure has then led to thermal decomposition, also known as "pyrolisis," which produces certain gases that support the assembly of CNOs.

What's exceptional about this method is that it does not need complex catalysts or harsh conditions. It doesn't need prolonged waiting times either. Furthermore, the fish scales can be turned into CNOs in less than 10 seconds.

Furthermore, his synthesis process yields CNOs with very high crystallinity. This is extremely hard to achieve in processes that use biomass waste as a starting material.

In addition, during synthesis, the CNOs' surface is selectively and thoroughly functionalized with -OH and -COOH groups.

This contradicts the surface of CNOs prepared with traditional methods, which are usually bare and have been functionalized through more steps.

Automatic Functionalization

Such an "automatic" functionalization has essential implications for the application of CNOs. When the surface of the CNO is not functionalized, the nanostructures are inclined to stick together, owing to an alluring exchange called "pi-pi stacking."

According to a related ScienceDaily report, this makes it so hard to disperse them in solvents, which is essential in any application that needs solution-based processes.

Nonetheless, since the proposed synthesis process produces functionalized CNOs, it enables excellent dispersibility in different solvents.

Related information about turning fish waste into something beneficial is shown on Access Agriculture's YouTube video below:

Check out more news and information on Fish and Nanotechnology in Science Times.