Preparation, characterization and biosorption properties of chitosan-mwcnts nanocomposite for removal of cadmium from aqueous solution



The removal of Cd (II) ions from aqueous solution by synthesized chitosan-mwcnts (ch-mwcnts) was investigated in a batch adsorption system. The morphological of modified chitosan was characterized by scanning electron microscopy (SEM), fourier transfer infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The effect of various factors such as; initial concentration of cadmium ions, initial pH and temperature of the solution for removal of Cd (II) was studied. The experimental isotherm data were analyzed by Langmuir, Freundlich, Dubinin–Radushkevich and Temkin models. Equilibrium data agreed well with Langmuir isotherm, Based on this model, the maximum adsorption capacity of nanocomposite of ch-mwcnts for Cd (II) was obtained to be 24.27 mg/g at pH=6. A pseudo-second order model has been proposed to correlate the experimental data (R2= 0.996). The thermodynamic parameters such as standard Gibb’s free energy (∆G˚), standard enthalpy (∆H˚), standard entropy (∆S˚) and activation energy (Ea) were evaluated by applying the Van’t Hoff and Arrhenius equations and were determined as -0.088  to -1.208 kJ/mol , 16.6 kJ/mol , 56  J/ mol. K and 5.58 kJ/ mol, respectively.