Sea water analysis

Update
5 July 2011

ION EXCHANGE

Approximate sea water analysis

Main dissolved ions in sea water
Cations
Ion	meq/L	g/L
Na⁺	479	11.02
Mg⁺⁺	109	1.31
Ca⁺⁺	21	0.42
K⁺	10	0.39
Anions
Ion	meq/L	g/L
Cl^–	560	19.88
SO₄^2–	57	2.74
HCO₃^–	2	0.12
Br^–	0.9	0.07

Total salinity of this example: about 620 meq/L and 36 g/L.
All g/L values as ion (not CaCO₃). Sea water has little bicarbonate and silica.
The pH value of sea water is always between 7.5 and 8.4.
The density of sea water is between 1.020 and 1.029 g/L.
The conductivity of sea water is about 50 mS/cm (50'000 µS/cm) @ 20 °C.

The salinity of sea water has a generally applicable average of 35 g/L.
A more detailed study gives:

Not all seas and oceans are the same
Baltic Sea	6 to 18 g/L
North Sea	32 g/L
Oceans	33 to 37 g/L
Mediterranean	38 g/L
Red Sea / Persian Gulf	38 to 43 g/L
Dead Sea	230 g/L

The salinity of sea water is too high to be treated by ion exchange; the most usual sea water desalination processes are reverse osmosis and distillation. See the salinity limit in the page about feed water.