Grantee Research Project Results

Final Report: A Low-Cost, In-Situ Bimetallic Reduction Prototype System for the Treatment and Remediation of Chlorinated Solvent-Contaminated Ground Waters

EPA Contract Number: 68D98116
Title: A Low-Cost, In-Situ Bimetallic Reduction Prototype System for the Treatment and Remediation of Chlorinated Solvent-Contaminated Ground Waters
Investigators: Loutfy, Raouf O.
Small Business: Materials and Electrochemical Research (MER) Corporation
EPA Contact: Richards, April
Phase: I
Project Period: September 1, 1998 through March 1, 1999
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (1998) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , SBIR - Waste , Small Business Innovation Research (SBIR)

Summary/Accomplishments (Outputs/Outcomes):

The objectives of this EPA-sponsored Phase I program were to design, develop and laboratory test the innovative Pd-C-Fe catalytic reduction system for the successful detoxification of chlorinated solvent-contaminated ground water. The basic process is to use bimetallic system, in which one low cost metal will sacrificially corrode or oxidize to generate sufficient potential on the second metal to evolve hydrogen from the reduction of water. The nacent hydrogen will then reduce halogenated organics to hydrocarbons and chlorides. The most active bimetallic system developed to date was the Pd-Fe system. While this system performs very well in detoxification of waste water, it suffers from significant performance deterioration as a result of loss of contact between the bimetals, the deactivation of the Pd by the oxidation product of Fe, and physical loss of Pd. Furthermore, water contaminates such as sulfur compounds results in permanent passivation of the system. These factors make this system economically unattractive. The Phase I effort, therefore, was focused on developing an advanced system that takes advantage of fast kinetic, low cost feature of the bimetallic system, but eliminates all its disadvantages. In this program, the Pd-C and a number of other catalysts have been synthesized, characterized and evaluated their performance using three different techniques. The catalyst activity of MER Pd-C has been compared with other state-of art catalyst systems such as Fe and Pd-Fe. MER's Pd-C-Fe catalyst system has demonstrated a successful complete dehalogenation of the major categories of ground water organic contaminants. This is a real breakthrough achievement. A pre-pilot test has been conducted using real-world contaminated ground water.

Preliminary performance evaluation and cost analysis have been completed for MER's Pd-C-Fe catalyst and compared to the existing technologies. It has been concluded that the MER Pd-C-Fe system

• Exhibits superior activity compared to the existing Fe or Pd-Fe system. An improvement factor of 2.5 has been observed over the Pd-Fe catalytic system for the dechlorination of chlorophenol.
• Eliminates the catalyst deterioration and Pd loss in the existing Pd-Fe systems, which have been the major obstacles to the commercialization of the Pd-Fe technology. No appreciable activity loss was observed over 12 cycles of catalyst application in the prototype cell and over 200 hours in the pre-pilot test with contaminated ground water.
• Completely detoxifies at a practical rate of a range of the most representative halogenated organic contaminants including TCE, PCE, vinyl chloride, methylene chloride, carbon tetrachloride and nitroethanol. The lifetime of the contaminants range from 5 to 50 minutes at the catalyst to liquid ratio of 8 x 10-3 (w/w).
• Enhances reactivity by 20% when MER porous iron is used as compared to iron powder based system. The porous iron also allows ease of handling and maintenance.
• Demonstrates excellent performance and stability at a level of pre-pilot testing with contaminated ground water over extended period of time.
• Shows the most versatility for ground water remediation of different contaminants.
• Is among the most affordable technologies based on preliminary cost analysis.

The key to MER's innovation is the introduction of a non-consumable, electron conductive phase in the catalyst to separate the precious metal from the electron donor. This arrangement, as has been demonstrated, prevents activity deterioration and loss of the precious metal, which have been the major problems associated with the existing bi-metallic systems.

The preliminary commercialization plan and financial analysis was prepared based on the results obtained in Phase I. The result indicates the viable commercial business can be created after demonstration of this technology in the field. This commercialization can create up to 100 new jobs and up to $20 million in revenue.

The MER Pd-C-Fe system offers an efficient, versatile and yet affordable alternative to ground water remediation and wastewater treatment.

Supplemental Keywords:

RFA, Scientific Discipline, Waste, Water, Economic, Social, & Behavioral Science Research Program, Toxics, Hazardous, National Recommended Water Quality, Remediation, Chemistry, Environmental Chemistry, Engineering, Chemistry, & Physics, Groundwater remediation, Market mechanisms, Hydrology, Drinking Water, Environmental Engineering, Trichloroethylene, hazardous waste treatment, groundwater contamination, cost effective, chemical contaminants, contaminant removal, groundwater, in situ remediation, solvents, drinking water contaminants, chlorinated solvents, TCE