Enhanced stability of hydrogen peroxide in the presence of subsurface solids

• Published in: Journal of contaminant hydrology Vol. 91; no. 3; pp. 312 - 326
• Main Authors: Watts, Richard J., Finn, Dennis D., Cutler, Lynn M., Schmidt, Jeremy T., Teel, Amy L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 14.05.2007; Elsevier Science
• Subjects: Catalyzed H 2O 2 propagations (CHP); catalyzed H2O2 propagations; Citrate; citrates; Citrates - chemistry; Earth sciences; Earth, ocean, space; Environmental Restoration and Remediation - methods; Exact sciences and technology; Fenton's reagent; Geologic Sediments; half life; hydrogen peroxide; Hydrogen Peroxide - chemistry; Hydrogen peroxide stabilization; Hydrogeology; Hydrology. Hydrogeology; Hydroxyl radical; in situ chemical oxidation; Malonate; Malonates - chemistry; oxidation; Phytate; phytic acid; Phytic Acid - chemistry; pollutants; slurries; Soil Pollutants - chemistry; soil transport processes; subsurface solids; Superoxide; superoxide anion; Superoxides - chemistry; United States; United States; Phytate; Fenton's reagent; Citrate; Catalyzed H 2O 2 propagations (CHP); Malonate; Superoxide; Hydrogen peroxide stabilization; Hydroxyl radical; stabilization; hydrogen peroxide; oxidation; concentration; transport; in situ; Catalyzed H2O2 propagations (CHP); propagation; oxygen; reagents; stability
• ISSN: 0169-7722; 1873-6009
• DOI: 10.1016/j.jconhyd.2006.11.004

The stabilization of hydrogen peroxide was investigated as a basis for enhancing its downgradient transport and contact with contaminants during catalyzed H 2O 2 propagations (CHP) in situ chemical oxidation (ISCO). Stabilization of hydrogen peroxide was investigated in slurries containing four characterized subsurface solids using phytate, citrate, and malonate as stabilizing agents after screening ten potential stabilizers. The extent of hydrogen peroxide stabilization and the most effective stabilizer were solid-specific; however, phytate was usually the most effective stabilizer, increasing the hydrogen peroxide half-life to as much as 50 times. The degree of stabilization was nearly as effective at 10 mM concentrations as at 250 mM or 1 M concentrations. The effect of stabilization on relative rates of hydroxyl radical activity varied between the subsurface solids, but citrate and malonate generally had a greater positive effect than phytate. The effect of phytate, citrate, and malonate on the relative rates of superoxide generation was minimal to somewhat negative, depending on the solid. The results of this research demonstrate that the stabilizers phytate, citrate, and malonate can significantly increase the half-life of hydrogen peroxide in the presence of subsurface solids during CHP reactions while maintaining a significant portion of the reactive oxygen species activity. Use of these stabilizers in the field will likely improve the delivery of hydrogen peroxide and downgradient treatment during CHP ISCO.