Sequential electrolytic oxidation and reduction of aqueous phase energetic compounds

Area of Science:

• Environmental Engineering
• Electrochemistry
• Remediation Technologies

Background:

• Soils and groundwater are often contaminated with energetic compounds from ammunition manufacturing.
• Conventional remediation strategies solely using oxidation or reduction have limitations.
• Electrolytic degradation offers a promising alternative for managing these contaminants.

Purpose of the Study:

• To evaluate the transformation of RDX and TNT in aqueous solutions using an electrolytic permeable reactive barrier (e-barrier).
• To investigate the effectiveness of sequential oxidation-reduction and reduction-oxidation processes.
• To assess the feasibility of an in-situ electrolytic approach for groundwater remediation.

Main Methods:

• Laboratory experiments using flow-through electrolytic reactors with porous media and mixed-metal oxide electrodes.
• Testing of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) transformation.
• Varying electrode sequences and including no-voltage control columns.

Main Results:

• Sequential oxidation-reduction achieved over 97% TNT and 93% RDX transformation.
• Sequential reduction-oxidation resulted in approximately 90% TNT and 40% RDX removal.
• No significant accumulation of known degradation intermediates was observed under sequential oxidation-reduction.

Conclusions:

• Electrolytic degradation using e-barriers is highly effective for RDX and TNT transformation.
• Sequential oxidation-reduction shows superior performance for these contaminants.
• The low power requirements suggest a cost-practical in-situ remediation solution.