Analysis of the kinetics of lead biosorption using native and chemically treated olive tree pruning

In this research, new biosorbents of olive tree biomass were obtained by acid and basic treatment of the raw material at 50 °C and 1 M of chemical agent concentration. A kinetic study of the biosorption of lead ions by olive tree pruning was analyzed according to six different kinetic models. The pseudo first, pseudo second, pseudo n-order, Elovich, solid diffusion and double exponential models were employed to study the kinetics. The biosorption kinetic data were successfully described with pseudo-nth order and double exponential models for all biosorbents. The double exponential model allowed estimating the values of external and internal mass transfer coefficients. The values of external mass transfer coefficient (ke) ranged from 16.2 × 10−6 to 1066 × 10−6 m min−1 and the internal mass transfer coefficient (ki) from 9 × 10−6 to 69.88 × 10−6 m min−1. On the other hand, the analysis of experimental data showed that chemical treatments of the biomass led to increase biosorption capacity of the raw biomass.