CARBON SEQUESTRATION POTENTIAL IN SIMULATED SALINE LAKE WATERS

Recent studies have examined different applications of established geologic formations as potential reservoirs for sequestering anthropogenic CO₂. This investigation tested simulated saline lake waters as mineralization sites for sequestering anthropogenic CO₂. Four saline lakes were simulated in the laboratory – Lake1 (Na-Mg-Cl-SO₄ type), Lake 2 (Mg-Na-Ca-Cl type), Lake 3 (Mg-Na-K-Cl type) and Lake 4 (Ca-Mg-Cl type). Two sets of experiments were conducted by diffusing CO_2(g) through each simulated lake over 30 days. The first set tested the carbonate system response to elevated CO_2(g). The second set of experiments replicated the same process but used ammonium hydroxide to elevate pH. Water samples were collected daily to test for cation loss via mineralization. Rapid mineralization occurred with the pH enhancer and cation activity was greatly reduced by as much as 38,000 mg/L Ca due to precipitation. This resulted in a mass of 100,000 mg/L of CO₂ being mineralized via Ca and Mg-carbonate precipitation. Under proper geochemical conditions, saline lake environments may therefore potentially serve a purpose in sequestering CO_2(g). Analyses are now underway using X-ray diffraction and scanning electron microscopy to characterize the newly precipitated carbonate minerals.