Crystallization kinetics from mixture Na2SO4/glycerol droplets of Na2SO4 by FTIR-ATR

- The method to calculate nucleation rate of Na2SO4 in mixed Na2SO4/glycerol is proposed by FTIR technology.
- Addition of glycerol affects the nucleation RH of Na2SO4 and delayed the crystallization of Na2SO4.
- The nucleation saturation decreases with the glycerol content.
- The nucleation rate as the function of solute saturation degree has been gained combining the E-AIM with classical theory.

The efflorescence of mixed Na2SO4/glycerol aerosols on the ZnSe substrate with various mole ratios (Na2SO4/glycerol = 1:1, 1:2, 1:4) has been studied in the relative humidity (RH) linearly decline process, using a situ Fourier transform infrared attenuated total reflection (FTIR-ATR) technique. The crystal ratio at a given RH can be gained by the absorbance of the band at 1132 cm−1, which shows the incomplete nucleation for mixed Na2SO4/glycerol aerosols and the decreased amount of the droplets crystallized at the lowest RH with the glycerol increase. Using the volume fraction of droplets that have yet to crystallize, the heterogeneous nucleation kinetics has been gained. By the Extended Aerosol Inorganics Model (E-AIM), the nucleation rate as the function of solute saturation degree has been gained for various mixed Na2SO4/glycerol aerosols.

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