Persulfate activation by glucose for in situ chemical oxidation.

Sodium persulfate has become the most popular oxidant source for the in situ chemical oxidation (ISCO) treatment of organic contaminants in the subsurface. The most common persulfate activators, iron chelates and base, are often ineffective in initiating the generation of reactive oxygen species in field applications. In this study, glucose was investigated as a persulfate activator in systems containing varying concentrations of sodium hydroxide using nitrobenzene as a hydroxyl radical probe and hexachloroethane as a reductant + nucleophile probe.

Mechanism of persulfate activation by phenols.

The activation of persulfate by phenols was investigated to further the understanding of persulfate chemistry for in situ chemical oxidation (ISCO). Phenol (pKa = 10.0) activated persulfate at pH 12 but not at pH 8, suggesting activation occurred only via the phenoxide form.

Oxidized starch solutions for environmentally friendly aircraft deicers.

Deicers currently used for aircraft deicing, including ethylene glycol and propylene glycol, pose significant threats to surface waters, as a result of high biochemical oxygen demand (BOD) and toxicity to aquatic organisms. Oxidized starch may provide a less toxic deicer with lower BOD. The freezing point depression of starch formulations oxidized using hydrogen peroxide and catalysts (i.

Persulfate activation by naturally occurring trace minerals.

The potential for 13 naturally occurring minerals to mediate the decomposition of persulfate and generate a range of reactive oxygen species was investigated to provide fundamental information on activation mechanisms when persulfate is used for in situ chemical oxidation (ISCO). Only four of the minerals (cobaltite, ilmenite, pyrite, and siderite) promoted the decomposition of persulfate more rapidly than persulfate-deionized water control systems. The other nine minerals decomposed persulfate at the same rate or more slowly than the control systems.

Treatment of polychlorinated biphenyls in two surface soils using catalyzed H₂O₂ propagations.

Two surface soils contaminated with polychlorinated biphenyls (PCBs) collected from Superfund sites in the New England region of the United States, Fletcher Paints and Merrimack Industrial Metals, were evaluated for field treatment at the bench level using catalyzed H(2)O(2) propagations (CHP-modified Fenton's reagent). The two soils were first evaluated for the potential for in situ treatment based on two criteria: (1) temperature (< 40 °C after CHP reagent addition), and (2) hydrogen peroxide longevity (> 24h). In situ CHP remediation was more applicable to the Fletcher soil, while the Merrimack soil was better suited to ex situ treatment based on temperature increases and hydrogen peroxide lifetimes.

Hydrogen peroxide stabilization in one-dimensional flow columns.

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H(2)O(2) propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart.

Persulfate activation by subsurface minerals.

Persulfate dynamics in the presence of subsurface minerals was investigated as a basis for understanding persulfate activation for in situ chemical oxidation (ISCO). The mineral-mediated decomposition of persulfate and generation of oxidants and reductants was investigated with four iron and manganese oxides and two clay minerals at both low pH (<7) and high pH (>12). The manganese oxide birnessite was the most effective initiator of persulfate for degrading the oxidant probe nitrobenzene, indicating that oxidants are generated at both low and high pH regimes.