A filtration material is provided for incorporation in a gas filter that includes an Activated Carbon, Impregnated with Copper, Silver, Zinc, Molybdenum, and Triethlyenediamine (ASZM-TEDA) medium and a macrocyclic organic material. The material is impregnated into the medium in proportions of between 1% and 5% of the medium. The material consists of molecules, each with a binding pocket for binding a metal ion. Also, a method is provided for impregnating porphyrin into a medium of ASZM-TEDA for incorporation in a gas filter. The method includes mixing porphyrin and ASZM-TEDA in a first ratio-by-weight of 1:4 of porphyrin to ASZM-TEDA as a mixture in a container; adding dichloromethane to the mixture in a second ratio-by-weight of 1:133 of porphyrin to dichloromethane as a solution in the container; stirring and refluxing the solution under nitrogen, filtering said mixture from the solution as a carbon residue; and drying the residue.