Open AccessWater adsorption and dynamics on kerosene soot under atmospheric conditions
Author(s) -
Ferry D.,
Suzanne J.,
Nitsche S.,
Popovitcheva O. B.,
Shonija N. K.
Publication year - 2002
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jd002459
Subject(s) - soot , adsorption , materials science , saturation (graph theory) , kerosene , nucleation , chemical engineering , chemical physics , chemistry , organic chemistry , combustion , mathematics , combinatorics , engineering
Morphology, microstructure and surface chemistry of laboratory made kerosene soot used as an aircraft soot surrogate have been studied to establish the correlation between the porosity and the mechanism of water adsorption on the soot surface. The quasielastic neutron scattering (QENS) technique has been used to characterize the dynamics of water confined in the soot pores network. Spectra above and below the water triple point T m describe the translational and rotational diffusion of water molecules adsorbed in 0.5 nm micropores, 2 nm supermicropores and ≥2 nm mesopores. Below T m an appreciable amount of liquid water exists in the soot micropores down to the lowest tropospheric temperatures. The depression in freezing temperature is related to the pore dimension. Water confined in the micropores appears to freeze completely only at T below 200 K showing that the nucleation process depends on the specific microporosity. At the saturation plume conditions ≅30% of adsorbed water has been transformed into ice. These results show that, in the upper troposphere, soot particles presenting the above‐mentioned properties will contain stable water/ice components inside the pores with 25% of unfrozen water.