A technique developed at Hitit University to increase the surface area of multi-walled carbon nanotubes, used in many fields from energy storage to the pharmaceutical industry, without loss through a rapid cooling-heating method, has been registered by the Turkish Patent and Trademark Office. With this work, Hitit University's number of patents has reached four.
Associate Professor Dr. Filiz Boran, a faculty member in the Department of Chemical Engineering at Hitit University's Faculty of Engineering, initiated the study to prevent product loss and chemical use that occur in the processing of multi-walled carbon nanotubes, which have wide applications in industry, using traditional methods.
Boran stated that thanks to the method she developed, carbon nanotubes are reduced to much smaller particles, thereby increasing their surface area and obtaining a porous surface.
Boran noted that her technique has many advantages over traditional techniques, explaining that in the traditional method, multi-walled carbon nanotubes are exposed to temperatures reaching 700 degrees Celsius and then processed using techniques such as ultrasound, mechanical cutting, and grinding, but these techniques require expensive equipment and long working times.
Boran also stated that these methods damage nanotubes and cause 90% product loss, emphasizing that the technique he developed can be easily applied with the help of a liquid nitrogen tank, without any product loss, and can be applied in a very short time.
Pointing out that the technique is quite simple and easy to apply, Boran continued:
"We don't use any chemicals here; we only use liquid nitrogen. Other chemical methods use highly concentrated acid solutions. There is thermal shock at temperatures between 600 and 700 degrees. In this technique, the yield is only 10%. Therefore, it is not a suitable method for industry. When using thermal stress at high temperatures, they will only have 100 kilograms of product left from 1 ton. There is a very large product loss, but with the technique we have developed, there is no product loss. Therefore, it is a technique that can be applied to industry much more and will offer more effective solutions."
Boran, noting that the method he developed could be called "cold burning" or "thermal shocking" in layman's terms, said, "Here, thermal shocking is performed by bringing the products from a very cold environment, at -196 degrees Celsius, in a liquid nitrogen environment to room temperature. By taking advantage of this, the product is broken down into smaller pieces. This increases the percentage of surface area and porosity of the material."
He added that the product is broken down into smaller pieces by taking advantage of this. Boran stated that the multi-walled carbonate tubes obtained through this method can be effectively used in filtration systems, the pharmaceutical industry, food transportation, and packaging sectors thanks to their increased surface area and porosity, adding:
"I think most importantly, it will increase its usability in the energy sector. The increased specific surface area and porosity of the products we have developed here will enable faster charging and discharging when used in energy storage and conversion systems and in the structures of electrode materials. Products developed with this technique will enable higher capacity energy storage. This will offer great opportunities in the creation, development, and storage of energy systems in super-capacity lithium-ion batteries and fuel cells."
Boran continued, "It's a much more economical technique because we have no product loss. We don't need extra expensive equipment or systems. There will be no chemical waste. Therefore, this technique will benefit us in waste treatment and waste disposal."
