Enhanced removal of toxic Congo red dye using multi walled carbon nanotubes: Kinetic, equilibrium studies and its comparison with other adsorbents

MWCNTs were used as an efficient adsorbent for rapid removal of hazardous Congo red dye (CR) from aqueous solutions; the whole adsorption process was well investigated and elucidated. The impact of several significant parameters such as contact time, pH, temperature and initial concentration were well studied and optimized. As a result of optimization the values of influential parameters such as contact time, pH, temperature, initial concentration and fixed adsorbent dose were found to be 60 min, 11, endothermic, 200 ppm and 0.05 g, respectively. The developed nano adsorbent shows an excellent potential (q(e), 352.11 mg/g; 92% of CR has been removed within 60 min) for removal of CR from the solvent phase. The adsorption kinetics and isotherm data were found to be well fitted and in good agreement with the pseudo-second order and Langmuir isotherm models, respectively. The efficient and rapid removal of the noxious CR dye using MWCNTs in a very short period of time, and the obtained maximum adsorption capacity of the developed adsorbent in comparison to the previously developed adsorbent establishes the significance of the work done. (C) 2015 Elsevier B.V. All rights reserved.