Utilization of <i style="">Erythrina variegata orientalis</i> leaf powder for the removal of cadmium

Abstract

Removal of cadmium, a priority pollutant, is carried out by abundantly and freely available <i style="">Erythrina variegata orientalis</i> (Indian coral tree) leaf powder. The extent of removal depends on initial concentration of cadmium in the solution, <i>p</i>H of the solution, temperature, etc. A significant increase in percentage removal of cadmium is observed as <i>p</i>H is increased from 2 to 4. The percentage removal of cadmium increases marginally for <i>p</i>H of 4 to 7. As the initial concentration of cadmium is increased from 23 to 188 mg/L, the % removal is decreased from 98.8 to 86.1%. Freundlich and Langmuir isotherm models well describe the data indicating favourable biosorption. The biosorption is endothermic, irreversible and follows pseudo-second-order kinetics, and rate constant is 0.23 g/(mg-min) for a dosage of 40 g/L. The equilibrium agitation time is 50 min.