Equilibrium and Kinetic Studies for the Biosorption of Cd (II) in Aqueous Solution onto Almond GumAuthor(s): Jameer Ahammad S, Sumithra S and Subha R
Batch adsorption process was carried out for the removal of cadmium (II) from aqueous solution using almond gum. The material was characterized using standard physio-chemical methods, SEM and FTIR studies. The adsorption isotherm was evaluated by means of Langmuir, Freundlich, Dubinin Radushkevich (D-R) and Temkin isotherm models. A maximum Langmuir adsorption capacity of 40.0 mg/g at 32°C was obtained for initial concentration of 10 mg/L, 20 mg/L, 30 mg/L and 40 mg/L. The order of the kinetics was also determined and adsorption of cadmium (II) followed second order kinetics which shows that physisorption may be involved in the process. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) showed that the reaction to be endothermic, spontaneous and increasing randomness of the solid solution interface. The cost of almond gum is economically effective compared to commercial activated carbon.