Sonication is a powerful technique to promote the dispersion of carbon nanotubes (CNTs) and enhance their solubility; this is necessary for CNT applications, especially in the biochemical and biomedical fields. In this study, batch experiments were conducted to evaluate the role of sonication energy on the dispersion of CNTs in the presence of a widely used anionic surfactant, sodium dodecylbenzene sulfonate (SDBS). It was observed that the concentration of dispersed CNTs in the SDBS solution depended on the sonication energy, but not the sonication time or output power of the sonicator alone. The amount of dispersed CNTs was positively correlated with the concentrations of SDBS and CNTs, and the length of the CNTs. The promotion of oxygen-containing functional groups on the dispersed CNTs was observed at relatively low sonication energies. The optimal energy, i.e. the minimum energy supplied by sonication to achieve a saturated suspension of dispersed CNTs in the SDBS solution, was CNT diameter-dependent, because of the larger vdW forces between tubes of smaller diameter. An exponential decay curve was constructed for the optimal energy values as a function of the outer CNT diameter, to assist in determining the energy needed to disperse CNTs. carbon nanotubes, sonication energy, dispersion, surfactant Citation:Yang K, Yi Z L, Jing Q F, et al. Sonication-assisted dispersion of carbon nanotubes in aqueous solutions of the anionic surfactant SDBS: The role of sonication energy.

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a b s t r a c tOrdered mesoporous Co 3 O 4 (3D) and the bulk counterpart Co 3 O 4 (B) were prepared by a nanocasting route and precipitation method, respectively. Pd was next loaded on both of them by an impregnation method. All catalysts were tested for the total oxidation of o-xylene in the temperature range of 150-300 • C. Mesoporous Co 3 O 4 (3D) exhibited better activity than Co 3 O 4 (B), and Pd addition further improved the catalytic activity of both the mesoporous and bulk Co 3 O 4 . The BET and TEM results indicated that the mesoporous catalysts had uniform channel dimensions and the mesostructure was little affected by Pd addition. The TPR and XPS data indicated that Pd was much more exposed on the surface of Co 3 O 4 (3D) than that of Co 3 O 4 (B). TPD results showed that Pd/Co 3 O 4 (3DL) could activate the oxygen species more easily than Pd/Co 3 O 4 (BL). Therefore, Pd/Co 3 O 4 (3DL) presented the best activity among the four catalysts and achieved 90% conversion of 150 ppm o-xylene at 249 • C at a space velocity of 60,000 mL g −1 h −1 .