Adsorption Of Ternary Metal System Onto The Sawdust Of Locust Bean Tree (Parkia biglobosa): Equilibrium, Kinetics And Thermodynamics Studies

The use of raw sawdust, RSD, of locust bean tree (Parkia biglobosa), a low-cost, locally available agroforestry waste as an adsorbent for removing a ternary mixture of heavy metals comprising of copper, lead and nickel (TMS) from aqueous solution was examined. Equilibrium data obtained from batch adsorption experiments were analysed with Langmuir, Freundlich and Temkin isotherm models, with Langmuir equation giving the best fit to the data. The effect of contact time, initial concentration and pH of the solution and dose of RSD on the efficiency of the sorption process was also evaluated. The kinetics of the sorption was studied using different models; it was observed to have followed pseudo–second order model with high R values and close agreement between the theoretical and experimental values of qe for all initial TMS concentrations studied. The thermodynamic parameters of the adsorption showed that the process was feasible, exothermic and accompanied with increased randomness