Inclusion phenomena of phosphate and ammonium ions in spherically shaped ice

Inclusion phenomena of phosphate and ammonium ions in ice crystals and the behaviour of both ions during melting of the ice crystals were experimentally investigated. The experiments were performed by forming spherically shaped ice from a solution containing phosphate and ammonium ions. Then, the ice was melted to determine the concentrations of phosphate and ammonium ions. The maximum concentration of phosphate and ammonium was observed around the center of the ice spheres. During melting, the concentrations of both ions in the initially effluent solution were higher than those in the later-effusing solution. When the ice spheres were introduced into a solution containing both ions, there appeared a change in the maximum adsorption amount, which was followed by a rapid decrease approaching an equilibrium value.