Modification of Multi-walled Carbon Nanotubes and Its Application for Removal of Direct Blue 86

In this study, the modification of multi-walled carbon nanotube (MWCNT) with a cationic surfactant (cetyl trimethyl ammonium bromide, CTAB) and its application for removal of Direct Blue 86 (DB86) was investigated. The raw and functionalized samples were characterized by Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The influence of operational parameters such as adsorbent dosage, initial dye concentration and pH were studied at 25oC. Understanding the mechanism of the adsorption, Langmuir and Freundlich models were used. The results indicate that the data for adsorption of DB86 onto raw and modified carbon nanotubes fitted well to Langmuir isotherm. The Langmuir adsorption capacities of raw and modified carbon nanotube for DB86 were established as 69.93 and 149.25 mg/g, respectively. Pseudo first and second-order models were adopted to evaluate data and elucidate the kinetic adsorption process. The rates of sorption were found to conform to pseudo-second order kinetic with good correlation. The adsorption experiments indicated that the capacity of modified carbon nanotubes is more significant than raw carbon nanotubes, thus it could be used as an effective adsorbent for removing anionic dyes from textile waste waters. J. Color Sci. Tech. 7(2013), 103-112©. Institute for Color Science and Technology