| Abstrakt: |
Changes in seawater chemistry, amounts and ordering of salts precipitated under a closed isotherm evaporation conditions of (45 °C) were probed in the present study to simulate the depositional modeling of salts sequence in nature under similar circumstances. The seawater samples were collected from two shorelines in the territory of Egypt facing the M.S. (Mediterranean Sea) and R.S. (Red Sea). The results reveal that during the process of evaporation (from 0 to 80% water loss), the investigated seawater chemistry exhibits an increase in TDS (total dissolved solids), salinity, density, and (EC) electric conductivity leading to the formation of MgSO4-enriched seawater brine. As well, the measured pH decreased from 8.9 to 7.57 (M.S.) and from 8.13 to 7.37 (R.S.) toward the formation of a semi-neutral aqueous medium. XRD analysis exhibits the aragonite (CaCO3) was first to precipitate out from both marine waters at ≤ 20% of the water evaporated, while more soluble halite (NaCl) precipitates from the brine at approximately 75% or even > 80% of the water evaporated. The total amounts of salts precipitated from a 1 L of M.S. and R.S. water were 47.85 g/L and 53.68 g/L, respectively. The average rate of evaporation was 16.63 mL/day and 14.0 mL/day, which was inversely proportional to the induced seawater salinity (M.S. = 31%) and (R.S. = 34.5%). Ultimately, the percentage of salts obtained from 1 L of M.S and R.S water was 21.46 cm3and 24.62 cm3, respectively, which corresponded to a thin lamina of 2.78 cm and 2.91 cm as appeared in the vertical cross-section for the respective seawater. |
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