Multiwalled Carbon Nanotubes as Adsorbents for the Kinetic and Equilibrium Study of the Removal of Alizarin Red S and Morin

Abstract

The multiwalled carbon nanotube has been used as an efficient adsorbent for the removal of Alizarin red S (ARS) and morin from wastewater. The influence of variables including pH, temperature, concentration of the dye, amount of adsorbents and contact time, and so forth on the removal of both dyes was investigated by the batch method. Graphical correlations of various adsorption isotherm models like Langmuir, Freundlich, Tempkin, and Dubinin−Radushkevich have been carried out. The adsorption of ARS and morin has been found to be endothermic and feasible in nature. Various thermodynamic parameters, such as Gibbs free energy, entropy, and enthalpy, of the ongoing adsorption process have been calculated. The kinetic studies suggest the process following pseudosecond-order kinetics and involvement of the particle-diffusion mechanism.