Abstract
To produce single-walled carbon nanotubes (SWNT) by catalytic decomposition of carbon-containing molecules on silica support, as-prepared SWNT are grown on the surface of catalyst support. A very high purity of SWNT is required in various specific applications. Therefore, a purification step is considerably important in commercial production of SWNT. The conventional method for purifying SWNT is chemical treatment with acid or base. However, drawbacks of chemical treatment are toxicity, high cost, and the structural change of purified SWNT. To purify SWNT, froth flotation was focused as a better technique to separate SWNT from the spent catalysts. In this research, carbon black was used as model for investigation of effect of various parameters in froth flotation operation on purity and recovery of carbon. Nonionic surfactant was founded to be superior to ionic surfactants in the separation process between carbon and silica because both of silica and carbon are negatively charged. Effects of surfactant concentration, carbon loading, air flow rate, and foam height were investigated in this work.
