Adsorption Thermodynamics of Modified Carbon Nanotubes to Unsymmetric Dimethylhydrazine

The adsorption performance of multi-walled carbon nanotubes(MWNTs) modified by NaOH to unsymmetrical dimethylhydrazine (UDMH) was investigated. The adsorption of UDMH on MWNTs accorded with the Freundlich-type and Langmuir-type isothermal adsorption equations within the temperature range of 296￣313K and the concentration range of 44.51￣211.41mg/L. Isothermal adsorption curve at different temperature and isosteric enthalpy of adsorption of UDMH indicate that the process of adsorption of UDMH on MWNTs is an endothermic process. Estimation of enthalpy of adsorption, Gibbs free energy, and entropy of adsorption indicate that there is no forming chemical bond, and the adsorption behavior was reasonably interpreted from mechanism.