Adsorption Kinetics and Isotherms of Cu (II) and Cd (II) onto Oxidized Nano Carbon Black

Abstract

A new kind of sorbent, Oxidized Nano Carbon Black (OCB), was prepared with the acid potassium permanganate. The adsorption kinetics,isotherms of Cu (II) and Cd (II) onto Nano Carbon Black(CB) and Oxidized Nano Carbon Black(OCB) were investigated. The experimental data were analyzed by Langmuir, Freundlich isotherm, Pseudo first order equation and Pseudo second order equation. The results demonstrated that the Langmuir isotherm provided a better fit to the experimental data of CB and the OBC fitted well into Freundlich adsorption isotherm. The adsorption capacity of Cu2+ and Cd2+onto oxidized Carbon black was significantly enhanced after modification. The maximum amount of CB was 16.129mg/g for Cu2+, 5.747mg/g for Cd2+, the maximum amount of OCB was 83.333mg/g for Cu2+, 10.3097mg/g for Cd2+, respectively. The Freundlich parameters of OCB were KF, Cu = 0.360, nCu = 1.16, KF, Cd = 1.777 and nCd = 3.086. The values of n > 1 indicated a favorable adsorption process. The study of adsorption kinetic showed that the adsorption stage of Cu and Cd onto sorbents could be divided into two stages: fast reaction and slow reaction. The adsorption kinetic model of metal on OCB followed pseudo second order model well (RCu2=0.985, RCd2=0.987) and the data of CB fitted pseudo first order model well (RCu2=0.983, RCd2=0.998).