TECHNOLOGIES / CHEMICAL OXIDATION / PERSULFATE
CHEMICAL OXIDATION: PERSULFATE
Persulfate-based in-situ chemical oxidation (ISCO) is a powerful remediation technology that uses sodium persulfate (Na2S2O8) to break down a wide range of organic contaminants, including chlorinated solvents (e.g., PCE, TCE) and petroleum hydrocarbons (e.g., BTEX). When activated, persulfate generates sulfate radicals (SO4•–), which are highly reactive oxidizing agents that effectively degrade contaminants in soil and groundwater. With extensive field experience, ISOTEC designs and implements persulfate-based treatment strategies tailored to site-specific conditions, using both injection and soil mixing methods for optimal distribution and effectiveness.
UNDERSTANDING THE PROCESS
Persulfate is a strong oxidant that can be used in its native state or chemically activated to enhance its reactivity. Activating persulfate generates sulfate radicals (SO4•–), which are among the most potent oxidizing agents used in remediation. These radicals drive powerful oxidation reactions that break down contaminants into harmless byproducts. The ability to activate persulfate in multiple ways makes it a highly versatile remediation tool, allowing for treatment in various geochemical conditions.
- Base (Alkaline) Activation: Raises pH to facilitate sulfate radical formation and improve oxidant stability.
- Chelated Iron Activation: Uses chelated Fe2+ to sustain sulfate radical generation while minimizing precipitation.
- Heat Activation: Speeds up reaction rates and promotes radical formation for enhanced contaminant degradation.
- MFR/Peroxide Activation: Produces both hydroxyl and sulfate radicals for aggressive oxidation.
- Carbohydrate Activation: Uses natural organic products to initiate and sustain sulfate radical production under various geochemical conditions.
ISOTEC applies to most suitable activation method based on site-specific conditions to ensure effective contaminant breakdown and optimal oxidant distribution.
COMPARING PERSULFATE ACTIVATION METHODS
KEY ADVANTAGES OF PERSULFATE
- Flexible Activation Options: Can be applied as an unactivated oxidant or enhanced with various activation methods to increase reactivity.
- Powerful Oxidation Potential: Generates sulfate radicals, which effectively break down a wide range of organic contaminants.
- Extended Subsurface Activity: Persists longer than some other oxidants, allowing sustained treatment over weeks to months.
IDEAL APPLICATIONS FOR PERSULFATE
Persulfate is most applicable at sites characterized by:
- Chlorinated solvents (PCE, TCE, DCE, VC)
- Petroleum hydrocarbons and fuel related impacts (BTEX, MTBE, TPH)
- Sites requiring extended oxidant persistence for longer-lasting treatment
- Low-permeability soils where longer oxidant lifespan improves contact with contaminants
ISOTEC has extensive experience implementing persulfate ISCO in diverse site conditions and optimizing treatment strategies to maximize effectiveness and ensure regulatory compliance.