Removal of Copper (II) Ions from the Effluent by Carbon Nanotubes Modified with Tetrahydrofuran

In this study, a carbon nanotube modified with tetrahydrofuran was first synthesized. After preparing the adsorbent, discontinuous adsorption experiments of copper metal were performed on the adsorbent. Atomic absorption spectrometry was used to measure the concentration of copper metal. In this paper also, the effect of contact time, adsorbent amount, PH, initial metal concentration and temperature were investigated. The experiments were performed at concentrations of ۲ ppm to ۳۵ ppm and at temperatures of ۳۰۳ to ۳۴۳ Kelvin. The results showed that the highest removal efficiency was obtained at PH about ۵. Equilibrium contact time for ۶ ppm concentration was obtained in ۳۰ minutes and the optimal adsorbent is ۰.۲ g. After optimizing these variables, the maximum absorption value was ۹۶.۳۳%. Kinetic studies of copper removal by synthesized adsorbent were performed. The results obtained for discontinuous experiments follow the quasi-quadratic kinetic model with (R۲ = ۰.۹۹۳۱). Also, equilibrium studies of adsorption show that the adsorption process is better consistent with the Tamkin isotherm (R۲ = ۰.۹۶۸۳). In thermodynamic analysis, it is observed that the adsorption process is an endothermic process due to the positive enthalpy changes ( j/(mol .(_^۰)K )) ۳۲۸۷.۳۲, and the positive sign of Gibbs free energy at temperature K۳۰۳ with value (۱۷۱۵.۵۳ j) shows, the process is non-spontaneous. It is also a sign of positive and equal entropy changes (۵.۱۸۷ J * -K), which indicates an increase in entropy during the adsorption process in the system. Therefore, the absorption process is associated with an increase in irregularities.

Keywords:

Adsorption , heavy metals , Copper Metal , Carbon Nanotube , Tetrahydrofuran