Palladium-Catalyzed Destruction of Nitro Aromatic-Contaminated Groundwater
Master's thesis Sep 2001-Mar 2003
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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Of the over 17,000 DoD sites that potentially require remediation, sites containing soil and groundwater contaminated by energetic compounds are prevalent Larson et al., 2001. Production of energetics such as 2,4,6-trinitrotoluene TNT, hexahydro-1,3,5 - trinitro- 1,3,5 -triazine RDX, and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrasocine HMX for use in munitions has created a DoD-wide problem due to improper disposal techniques Price et al., 2001, Nitro aromatic compounds NACs similar to those used in explosives can also be found in insecticides, herbicides, pharmaceuticals, dyes, plastics, and many other commonly used products. The natural breakdown of these contaminants creates byproducts such as amines, which are known neurotoxins and carcinogens. The focus of this study was to determine the effectiveness of using a palladium Pd catalyst to reductively destroy NAC-contaminated groundwater under various conditions and to assess the feasibility of using a catalytic reactor in a horizontal flow treatment well HFTW system. Experimental results indicate reaction rates are dependent on both pH and reductant concentration in all experimental catalystreductant systems. Catalyst poisoning was seen at high contaminant concentrations in systems where molecular hydrogen was used as a reductant at low concentrations. However, no such effect was seen when using formate as a reductant and it was also observed that destruction rates were greater when formate, rather than hydrogen, was used as a reductant. Based on experimentally determined reaction rates and removal efficiencies, it appears there is promise for in-well use of Pd catalysis with a formate reductant as part of an HFTW system.
- Water Pollution and Control