Kinetics modelling of Cu(II) biosorption on to coconut shell and Moringa oleifera seeds from tropical regions

Adsorption kinetic studies are of great significance in evaluating the performance of a given adsorbent and gaining insight into the underlying mechanism. This work investigated the sorption kinetics of Cu(II) on to coconut shell and Moringa oleifera seeds using batch techniques. To understand the mechanisms of the biosorption process and the potential rate-controlling steps, kinetic models were used to fit the experimental data. The results indicate that kinetic data were best described by the pseudo-second-order model with correlation coefficients (R 2) of 0.9974 and 0.9958 for the coconut shell and Moringa oleifera seeds, respectively. The initial sorption rates obtained for coconut shell and Moringa oleifera seeds were 9.6395×10−3 and 8.3292×10−2 mg g−1 min−1, respectively. The values of the mass transfer coefficients obtained for coconut shell (1.2106×10−3 cm s−1) and Moringa oleifera seeds (8.965×10−4 cm s−1) indicate that the transport of Cu(II) from the bulk liquid to the solid phase was quite fas...