Adsorption of Cu2+ and Pb2+ Ions by Pontederia rotundifolia (L.f.) (Pontederiaceae) and Salvinia biloba Raddi (Salviniaceae) Biomass

Materials of different origins have been applied as adsorbents in the treatment of metal-containing liquid solutions. In this study, we evaluated the potential of the dry biomass of two species of macrophytes in the adsorption of Cu 2+ and Pb 2+ ions from aqueous solution. The investigation included analyses of particle size, pH at the point of zero charge (pH PZC ), kinetics of adsorption of the metal ions from the solution (equilibrium time × removal efficiency), and generation of adsorption isotherms. Results showed that particle size was not a determining factor for adsorption efficiency and capacity. The point of zero charge was similar between the adsorbents. Equilibrium times were 120 min for Pontederia rotundifolia and 240 min for Salvinia biloba . There was a high rate of removal of the metal ions from the solution, which occurred in the first minutes for S. biloba and in seconds for P. rotundifolia , at all initial concentrations tested. Equilibrium data fitted the Langmuir model. The adsorbent S. biloba is recommended for Cu 2+ removal from solutions, while both adsorbents can be indicated for removal of Pb 2+ . The biomass of P. rotundifolia and S. biloba has promising for application in systems aimed at the treatment or filtering of liquid solutions with the Cu 2+ and Pb 2+ ions, features being highlighted by the fast removal speed, good adsorption capacity, and low cost.