Effects of gas bubbling on water-solubilization of carbon nanotube using microplasma generated in water

In this study, influences of gas bubbling on water-solubility of single-walled carbon nanotubes (SWCNTs) based on microplasma treatment in water were investigated. Oxygen (O2), argon (Ar), nitrogen (N2) and carbon dioxide (CO2) were used as the bubbling gases. Bubbling of O2, Ar and N2 enhanced the O⁎ and H⁎ radicals produced by the microplasma in water and the solubility of SWCNT was increased more than two times compared to that without gas bubbling. On the other hand, the solubility was very poor in case of CO2. The negative effect of CO2 on the solubility might be due to the decrease of radicals, which were scavenged by carbonate ion generated by dissociation of CO2 in water, and caused by the reaction of radicals with CO2 or CO rather than those with SWCNT.