Foundry Odor Removal Using Hypochlorous Acid Aqueous Solution

In this paper, a method to deodorize ammonia and formaldehyde generated in a foundry using an aqueous solution of hypochlorous acid is reported. Air containing ammonia or formaldehyde was absorbed by an aqueous solution of hypochlorous acid, and the concentration of ammonia and formaldehyde before and after absorption, the type of ions in the solution, and the concentration of residual chlorine were measured. The results revealed that ammonia and formaldehyde deodorized upon oxidation in an aqueous solution of hypochlorous acid. However, the oxidation of formaldehyde with hypochlorous acid was only efficient in the presence of an adsorbent. The results have revealed the possibility of reducing foundry odors using a hypochlorous acid solution.