Dehalogenation of halogenated aliphatic organic compounds in the presence of the bimetallic system palladized iron

Saturated and unsaturated chlorinated aliphatic hydrocarbons containing one to three carbons are commonly used as industrial solvents. These solvents are often found as contaminants in groundwater through improper disposal and many of them are carcinogenic. Remediation of groundwater containing these chlorinated compounds is of obvious importance. Methods such as air stripping and carbon adsorption involve the physical transfer of these contaminants onto activated carbon, and that does not diminish their toxicity. Other methods such as U.V. irradiation in the presence of ozone, hydrogen peroxide, or TiO₂, are not cost effective for large volume contamination problems such as polluted lakes, rivers and streams. Elemental iron has been shown to dechlorinate low molecular weight chlorinated aliphatic compounds but the observed end products were still partially chlorinated. We have established that the bimetallic system palladized iron (0.05% Pd) is preferable to elemental iron for the rapid and complete hydrodechlorination of 1- and 2-carbon chlorinated compounds with minimal loss of palladium. The major product observed from the hydrodechlorination of the 2-carbon chlorinated compounds was ethane. Methane was the major product observed from the hydrodechlorination of the 1-carbon chlorinated compounds. The palladized iron bimetallic system is also capable of reducing CFC's, nitro-organic compounds and inorganic species such as nitrate ions