Removal of chromium (VI) from polluted water using carbon nanotubes supported with activated carbon

The environmental application of carbon nanotubes supported by activated carbon to remove chromium (VI) ions from polluted water was investigated. The experimental conditions that enhance the adsorption of Cr (VI) by carbon nanotubes have been studied. These conditions include the initial concentration of Cr (VI), the pH, the dosage of adsorbent, the contact time and the agitation speed. The activated carbon either alone or being coated with carbon nanotubes has be characterized by field emission scanning electron microscopy. A fractional factorial design was used to obtain a complete randomize experiment statistically. Adsorption isotherms have been applied to study the kinetics of the adsorption behavior and to determine the adsorption capacity of the absorbents. Regression analysis was used to study the empirical statistics of the experiment and to identify the significance of the parameters used to enhance the adsorption capacity. It was found that the activated carbon coated with carbon nanotubes is considered as an excellent adsorbent to Cr (VI) ions with an adsorption capacity of 9.0 mg/g.