A Natural Zeolite Permeable Reactive Barrier to Treat Heavy-Metal Contaminated Waters in Antarctica: Kinetic and Fixed-bed Studies

Ion exchange characteristics of Cu2+ on the natural zeolite clinoptilolite at 2 and 22°C are presented to facilitate the development of a permeable reactive barrier (PRB) to treat heavy-metal contaminated waters in Antarctica. A one-dimensional mass transfer transport model describing non-equilibrium sorption of Cu2+ in fixed-bed flow reveals that saturation capacities are independent of flow rate, but mass transfer coefficients increase with water velocity. Clinoptilolite capacity in fixed-beds is approximately 50% the capacity in equivalent batch systems, and mass transfer coefficients are between two and eight times batch-estimated values. Fixed-bed performance is significantly reduced at cold temperature, with breakthrough points and saturation capacities at 2°C between 60 and 65% less than operation at 22°C. The detrimental effects of cold temperature on fixed-bed performance will have significant implications for the design of a natural zeolite PRB to treat heavy-metal contaminated waters in Antarctica or other cold regions.