Adsorption Isotherm, Kinetic, Thermodynamic, and Desorption Studies of Lanthanum and Dysprosium on Oxidized Multiwalled Carbon Nanotubes

The adsorption behavior of La(III) and Dy(III) onto multiwalled carbon nanotubes oxidized (MWCNTs-oxidized) with concentrate nitric acid as a function of pH and adsorbent dosage was studied by batch technique. Maximum adsorption uptakes, according to the Langmuir model were obtained as 99.01 mg/g for La(III) and 78.12 mg/g for Dy(III). The results showed that adsorption process of both metals ions followed well the pseudo-second-order kinetics. The results of Thermodynamic parameters showed that the adsorption of La(III) and Dy(III) onto MWCNTs-oxidized is a feasible, spontaneous, and exothermic process. The results of desorption indicated that most of the adsorbed La(III) and Dy(III) can be easily desorbed from MWCNTs-oxidized at low pH values.