Size changes associated with metal adsorption onto modified bone gelatin beads

Significant quantities of heavy metals will adsorb onto modified bone gelatin beads. As this adsorption occurs, the bead can undergo a substantial volume change. Research has shown that the equilibrium bead diameter was a function of the solution pH and the ion concentration in the solution. Here, we demonstrate that under certain conditions, the volume of the beads that absorbed the metal was only 35% of the bead volume when no metal was adsorbed. By taking advantages of these size changes, a fluidized‐bed separator can be operated such that natural segregation of loaded beads occurs. This phenomenon may facilitate the design of continous separators for the recovery and concentration of heavy‐metal‐contaminated waters. These concepts are demonstrated using Cu²⁺ adsorption onto such beads.