The Chemistry of Drying an Aqueous Solution of Salts

The fate of salts in drying aqueous solution was investigated. In the drying of acidic solutions, weak acid ions and chloride ions combine with protons and evaporate, depending oil the proton concentration. In the drying of alkaline solutions, weak acid ions evaporate or remain as salts depending oil the ratio of the concentrations of excess nonvolatile cations (the difference between concentrations of nonvolatile cation and nonvolatile anion) to volatile anions defined as Delta CA. Under neutral and alkaline conditions, the fate of nitrite depends not only oil Delta CA but also on the drying speed. Nitrite is converted to N(2), which is formed by reacting nitrite with ammonium (denitrification), NO and NO(2), HONO and salts. In urban areas, nitrite and ammonium can appear in high concentrations in dew. HONO in the atmosphere affects the ozone concentration, but dew formation decreases the concentration of HONO. If chemical denitrification occurs, nitrogen species will decrease in the environment, and as a result, the ozone concentration could decrease. Ozone levels show an ozone depression when dew formed, and a Box model simulation showed an ozone depression by decreasing HONO levels.