How is air used to remove bromine from a dilute solution?

In the industrial extraction of bromine from dilute solutions, such as seawater, the element is first liberated from bromides through chemical displacement using chlorine in the presence of sulfuric acid.12

Once the bromine is released, a current of air is blown through the solution to remove it, resulting in a very dilute mixture of bromine and air. This gaseous mixture is then processed to concentrate the bromine. Depending on the specific industrial method, the bromine may be absorbed in sodium carbonate or mixed with sulfur dioxide and passed through a tower of trickling water to produce a solution significantly richer in bromide ions than the original source. Subsequent treatment with chlorine then allows for the collection of the bromine in a much more concentrated form.12