EQUILIBRIUM STUDIES IN NATURAL FLUIDS - USE OF SYNTHETIC SEAWATER ANDOTHER MEDIA AS BACKGROUND SALTS

A synthetic sea water (SSWE), containing Na+, K+, Mg2+, Ca2+, Cl- and SO42-, is proposed for use as a standard medium in equilibrium studies related to marine chemistry. Chemical physical properties of syntheti c sea water in the ranges 0 less-than-or-equal-to S parts per thousand 45 and 0 less-than-or-equal-to T(degrees-C) less-than-or-equal-to 45 (1 atm.pressure) are given. Alternative standard solutions representat ive of sea water, containing NaCl only or a mixture of NaCl and NgCl2, are also proposed. The use of these media in equilibrium studies is d iscussed. In order to make thermodynamic studies in marine chemistry e asier, conversion factors for all the types of concentration scales ge nerally used have been calculated and are reported. Some properties an d conversion factors for major sea salts, NaClO4, tetralkylammonium sa lts (often used as reference salts for the low tendency of ClO4- and t etralkylammonium cations to form complexes with cations and anions, re spectively) are also reported. The speciation of SSWE is discussed on the basis of a complex formation model.