THERMODYNAMIC MODEL OF THE SYSTEM H-NH4+-NA+-SO42--NB3--CL--H2O AT 298.15 K()

A multicomponent mole-fraction-based thermodynamic model of the H+-NH4 +-Na+-SO42--NO3--Cl--H2O system is used to represent aqueous-phase act ivities, equilibrium partial pressures (of H2O, HNO3, HCl, and NH3), a nd saturation with respect to 19 solid phases (NH4)(2)SO4(cr), (NH4)(3 )H(SO4)(2(cr)), NH4HSO4((cr)), NH4-NO3(cr), NH4Cl(cr), Na2SO4 . 10H(2) O((cr)), Na2SO4(cr), Na3H(SO4)(2(cr)), NaHSO4 . H2O(cr), NaHSO4(cr), N aH3(SO4)(2) . H2O(cr), NaNO3(cr), NaCl(cr), NH4HSO4 . NH4NO3(cr), (NH4 )(2)SO4 . 2NH(4)NO(3(cr)), (NH4)(2)SO4 . 3NH(4)NO(3(cr)), (NH4)(2)SO4 . Na2SO4 . 4H(2)O((cr)), Na2SO4 . NaNO3 . H2O(cr), 2NaNO(3) . NH4NO3(c r). The model is valid for concentrations from infinite dilution to sa turation (with respect to the solid phases) and to about 40 mol kg(-1) for acid sulfate systems which can remain liquid to concentrations ap proaching the pure acid. Parameters for H-2-SO4-H2O interactions were adopted from a previous study, and values for other binary (water-elec trolyte) and ternary (water and three ions) interactions were determin ed from extensive literature data for salt solubilities, electromotive forces, osmotic coefficients, and vapor pressures. The model is compa red with solubility measurements for the quaternary ion systems H+-Na-SO42--Cl--H2O and NH4+-Na+-SO42--Cl--H2O.