Removal of Chlorine Gases from Streams of Air Using Reactive Zirconium Hydroxide Based Filtration Media

Zirconium hydroxide and zirconium hydroxide impregnated with triethylenediamine (TEDA) were evaluated for their ability to remove toxic chlorine gases, namely Cl-2, COCl2, and HCl from streams of air in respirator applications. Zirconium hydroxide displayed a high capacity for the removal of HCl; however, the ability of zirconium hydroxide to remove Cl-2 and COCl2 was relatively low. The removal of Cl-2 and COCl2 greatly improved upon impregnation of zirconium hydroxide with TEDA. The improved performance was attributed to the ability of TEDA to promote the hydrolysis of Cl-2 and COCl2, leading to the formation of HCl which was subsequently removed via reaction with hydroxyl groups associated with zirconium hydroxide. XPS analysis revealed the presence of both terminal and bridging hydroxyl groups associated with zirconium hydroxide, with only the terminal hydroxyl groups participating in the removal of reactant or reaction product HCl.