Association of cadmium with MnO2 particles generated during permanganate oxidation.

Particle filtration and cadmium sorption studies were performed at selected time points during reaction of potassium permanganate with trichloroethylene under varied reaction matrix conditions. The purpose of the studies was to determine the potential impact of manganese oxides particle generation, a by-product of the permanganate reaction, on subsurface metal mobility, with cadmium serving as a representative metal of interest in the environment. Results of the studies indicate that the association of cadmium with the manganese oxides is a function of (1) particle concentration, (2) pH, (3) the presence of calcium in the reaction matrix, and (4) the rate of particle generation and agglomeration. Based on these findings, it is important to give careful consideration to subsurface conditions that can potentially impact the mobility of metals present naturally or as co-contaminants. If subsurface conditions are not appropriately characterized and planned for, deleterious effects could result, including long-term release of metals initially sorbed onto generated particles. Alternatively, the generated manganese oxides may serve as a long-term means of immobilizing metals within the subsurface.