The H2SO4-H2O System

The importance of sulfuric acid in aerosol formation in a humid environment has been emphasized in a number of studies (Kiang et al., 1973 Mirabel and Katz, 1974 Jaecker-Voirol and Mirabel, 1989 Kulmala and Laaksonen, 1990 Laaksonen et al., 1995). It is instructive to study first this simplified binary system before starting the discussion of the more complicated atmospheric aerosol systems. 

Particle Size Growth Factor without Kelvin Effect, Dp / D 

FIGURE 9.14 Vapor pressure of sulfuric acid as a function of temperature using the Ayers et al. (1980) and Kulmala and Laaksonen (1990) estimates. Reprinted with permission from Kulmala, M. and Laaksonen. A. Binary nucleation of water sulfuric acid system. Comparison of classical theories with different H2SO4 saturation vapor pressure, J. Chem. Phys. 93, 696-701. Copyright 1990 American Institute of Physics. 

Thus (PH 504/ 504) 1.0017, and in this case the Kelvin effect is negligible the increase in water vapor pressure due to the droplet curvature is only 0.166% above that of a flat surface. Say the ambient relative humidity is increased to 90%. The particle size growth factor at this relative humidity is 2.12. Thus the 1 fxm diameter drop at 50% RH will grow to become a drop of (2.12/1.48) (1) = 1.43 /xm at 90% RH. 

FIGURE 9.15 Equilibrium vapor pressure of H2SO4 in a mixture with water over a flat surface as a function of composition and temperature. 

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The most convenient method for representation of enthalpy data for binary J solutions is by enthalpy/ concentration (Hx) diagrams. These diagrams are graphs T of the enthalpy plotted as a function of composition (mole fraction or mass fraction of one species) with temperature as parameter. The pressure is a constants and is usually 1 atmosphere. Figure 13.10 shows a partial diagram for the H2SO4/H2O system. 

Figure 3. Calculated S 0 ratio (left hand axis), as well as weight percentage of sulfuric acid (right hand axis), for the H2SO4/H2O system measured as a function of sample temperature, with a constant water partial pressure of 1 x lO" and 3 x Kf Torr, represented by solid and open circles respectively. Also shown are the theoretically predicted bulk values for both, 1 x lO" Torr (solid line) and, 3 x 10 Torr (dotted line) calculated from (70).

V. INFLUENCE OF IONIC EQUILIBRIUM IN THE C11SO4-H2SO4-H2O SYSTEM ON THE FORMATION OF IRREGULAR ELECTRODEPOSITS OF COPPER... 

The most suitable way to analyze the ionic equilibrium in the CUSO4-H2SO4-H2O system was the examination of electrodeposition processes at overpotentials outside the plateau of the... 

The liquid-vapour equilibrium in the HF-H2SO4-H2O system at 22 °C has been determined by a dynamic method for the range of pressure 7.0—348.2 Torr. The extraction of HF into di-isoamyl methylphosphonate from the HF-HCl-HjO system increases as the HF content rises on the other hand, the extraction of HCl decreases as the HF content rises. 

PRZ/WIS] Przepiera, A., Wisniewski, M., Dabrowski, W., Jablonski, M., Enthalpy of solution and effect of temperature on activity coefficients in the MSO4-H2SO4-H2O system, J. Therm. Anal, 50, (1993), 1139-1143. Cited on pages 191, 425, 426. 

FIGURE 10.10 Free energy of cluster formation, AG(nA, B), for binary nucleation. (a) Schematic diagram of saddle point in the AG surface, (b) AG surface for H2SO4-H2O system at 298 K. 

Nikolic ND, Pavlovic LjJ, Krstic SB, Pavlovic MG, Popov KI (2008) Influence of ionic equilibrium in the CUSO4-H2SO4-H2O system on the formatimi of irregular electrodeposits of copper. Chem Eng Sci 63 2824-2828... 

Due to the ionic equilibrium of the species in the CUSO4-H2SO4-H2O system (the most often employed electrolytes for the electrodepositiOTi of copper are sulfate ones), the shape of powder particles depends on CUSO4 and H2SO4 concentrations [32-34]. For a constant H2SO4 concentration, the ion concentration decreases with increasing Cu concentration that is manifested by the change of shape of powder particles from the cauliflower-like to dendritic (Mies. 

Due to the ionic equilibrium of the species in the CUSO4-H2SO4-H2O system (Fig. 3.2), the quantities of evolved hydrogen and hence morphologies of powdered copper deposits depend strongly on the... 

Reardon E. J. and Beckie R. D. (1987) Modelling chemical equilibria of acid-mine drainage the FeS04—H2SO4-H2O system. Geochim. Cosmochim. Acta 51, 2355—2368. 

With the possible exception of the HCIO4—H2O system, higher acidities than that of 100 per cent H2SO4 can be obtained only in non-aqueous systems, and these may be somewhat arbitrarily... 

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