Formation of molecular chlorine in dark condition: Heterogeneous reaction of ozone with sea salt in the presence of ferric ion

Abstract

Uptake coefficients of O 3 on NaCl and synthetic sea salt (SSS) were found to be enhanced from < 10 −5 to ∼ 3.5 × 10 −2 in the presence of water‐soluble Fe 3+ in the Fe/Na weight ratio larger than 0.1%. Cl 2 release was observed without radiation in the reaction of O 3 and a FeCl 3 /NaCl mixture with surface adsorbed water at the yields of 0.48 and 0.28 for Fe/Na ratio of 1.0 and 0.5 weight %, respectively. Only Br 2 release was observed for a FeCl 3 /SSS sample. These results imply that when bromide is deficient in sea salt, Cl 2 would be released from the sea salt with the coexistence of Fe 3+ . The estimate was made to show that the Cl 2 releasing rate can be high enough to explain sporadically observed Cl 2 at nighttime in a coastal area.