Innovative Techniques for Decontamination of Boron Nitride Nanotubes: A Recent Study

Boron nitride nanotubes (BNNTs) are hollow cylindrical structures that have remarkable properties such as high strength, light weight, and thermal stability. These characteristics make them attractive for various applications in aerospace, electronics, biomedicine, and energy storage. However, one of the challenges in producing BNNTs is to remove the unwanted impurities that form during the synthesis process, such as boron nitride cages and boron particles.

A Novel Approach to Purify BNNTs

A team of researchers from Rice University, led by Professor Angel Martí, has developed a novel approach to purify BNNTs using phosphoric acid and fine-tuning the reaction conditions. Their study was published in Chemistry of Materials.

The researchers discovered that phosphoric acid can act as a wetting agent for BNNTs, meaning that it can penetrate the nanotubes and dissolve the impurities inside them. By adjusting the temperature and concentration of the acid, they were able to selectively remove the boron nitride cages and boron particles without destroying the nanotubes.

The Benefits of High-Purity BNNTs

The purification method developed by the Rice team can produce BNNTs with high purity and quality, which can enhance their performance and functionality for various applications. For example, high-purity BNNTs can improve the electrical conductivity and mechanical strength of composite materials, enable the development of new biomedical imaging or hydrogen storage devices, and withstand extreme temperatures in spacecraft.

Other Applications of BNNTs

Besides the applications mentioned above, BNNTs have also been explored for other purposes such as catalysis, optoelectronics, sensors, and biomaterials. Some of the advantages of BNNTs over carbon nanotubes (CNTs) in these fields are:

• BNNTs have a wide band gap (~5.5 eV) that can be tuned by doping or functionalization, making them suitable for light-emitting devices, photodetectors, solar cells, and field-effect transistors.
• BNNTs are electrically insulating but can be made conductive by doping or coating with metals or polymers, allowing them to be used as electrodes, catalyst supports, or gas sensors.
• BNNTs are highly hydrophobic but can be functionalized with various molecules to enhance their biocompatibility, solubility, or targeting ability, enabling them to deliver drugs, genes, or contrast agents to specific tissues or organs .
• BNNTs have a high neutron capture cross-section due to the presence of boron atoms, making them potential candidates for neutron capture therapy (NCT), a technique to treat cancer by irradiating boron-containing compounds with neutrons .

The researchers hope that their method can make BNNTs more widely available and affordable for industry and academia. They also plan to explore other ways to synthesize and manipulate BNNTs for different purposes.