Biosorption of Copper (II) on Dry Fruit by Product: Characterization, Kinetic and Equilibrium Studies

Biosorption of copper (II) using walnut shell powder (WNSP) appeared to be an efficient and effective decontamination method. XRD revealed the amorphous nature of the biosorbent and absence of metallic phase in it while FT - IR spectra indicated the surface heterogeneity in terms of functional groups. Removal of copper (II) by walnut shell powder followed a fast kinetic at 30 degrees C +/- 2 degrees C. Three typical kinetic models namely elovich, pseudo first and second order equations were analyzed to interpret the kinetic data. Pseudo second order kinetic enumerated the biosorption of copper (II) onto walnut shell powder best. Adsorption isothermal data was examined by classical two parameters (Langmuir, Freundlich, Dubinin-Radushkevic) and three parameters (Redlich-Peterson and Toth) models. With the aid of these models various aspects of copper (II) biosorption onto walnut shell powder were explored. Coefficient of determination (R-2) was used as the criteria of best fit for a model. Based on R-2 among two parameters models Langmuir isotherm enumerated the experimental data best and among three parameters models Redlich-Peterson isotherm gave the best description of the work conducted.