Molecular Dynamics Simulations on Evaporation of Droplets with Dissolved Salts

Abstract

Molecular dynamics simulations are used to study the evaporation of water droplets containing either dissolved LiCl, NaCl or KCl salt in a gaseous surrounding (nitrogen) with a constant high temperature of 600 K. The initial droplet has 298 K temperature and contains 1,120 water molecules, 0, 40, 80 or 120 salt molecules. The effects of the salt type and concentration on the evaporation rate are examined. Three stages with different evaporation rates are observed for all cases. In the initial stage of evaporation, the droplet evaporates slowly due to low droplet temperature and high evaporation latent heat for water, and pure water and aqueous solution have almost the same evaporation rates. In the second stage, evaporation rate is increased significantly, and evaporation is somewhat slower for the aqueous salt-containing droplet than the pure water droplet due to the attracted ion-water interaction and hydration effect. The Li + -water has the strongest interaction and hydration effect, so LiCl aqueous droplets evaporate the slowest, then NaCl and KCl. Higher salt concentration also enhances the ion-water interaction and hydration effect, and hence corresponds to a slower evaporation. In the last stage of evaporation, only a small amount of water molecules are left in the droplet, leading to a significant increase in ion-water interactions, so that the evaporation becomes slower compared to that in the second stage.

Insights into the morphology of multicomponent organic and inorganic aerosols from molecular dynamics simulations

“…S1 of the Supplement of the current study. The SPC/E model (Berendsen et al, 1987) was used for water and a two-site model (Tsolou and Mavrantzas, 2008;Wang et al, 2013) was adopted for treating nitrogen and oxygen molecules. SPC/E is a simple water model with low computational cost and includes a term for the corresponding polarization energy.…”

Insights into the morphology of multicomponent organic/inorganic aerosols from molecular dynamics simulations

“…Additional parameters for MBTCA can be found in the Section S1 of the Supplement 5 of the current study. The SPC/E model (Berendsen et al, 1987) was used for water and a two-site model (Tsolou and Mavrantzas, 2008;Wang et al, 2013) was adopted for treating nitrogen and oxygen molecules. The bond lengths of water, nitrogen and oxygen molecules, and of the bond bending angles of water molecules were kept constant in the simulations using the SHAKE algorithm (Miyamoto and Kollman, 10 1992).…”

Study on CO2 gasification properties of coal gasification wastewater slurry

“…This phenomenon can be understood from the following viewpoint: CGWS is prepared from wastewater that contains many salt ions, and water molecules tend to be regularly arranged around salt ions due to their hydration. In addition, the interaction strength between salt ions and water molecules is higher than the strength of the weak hydrogen bonds between water molecules, so the presence of a large amount of salts slows down the evaporation rate of water molecules in CGWS, 27 and the higher the salt concentration, the slower the evaporation rate 28 …”

“…In addition, the interaction strength between salt ions and water molecules is higher than the strength of the weak hydrogen bonds between water molecules, so the presence of a large amount of salts slows down the evaporation rate of water molecules in CGWS, 27 and the higher the salt concentration, the slower the evaporation rate. 28 In the pyrolysis stage, both CWS and CGWS mainly produce CH 4 and a small amount of CO 2 and CO, but the CH 4 generation rate for CGWS is significantly higher than that for CWS. According to Figure 5, it is found that at the same temperature, CGWS has a faster CH 4 generation rate and also generates C 8 H 16 and C 8 H 18 which CWS does not.…”