Laserfiche WebLink
i <br /> Chemical Activation: <br /> There are four primary methods of activation of the persulfate. <br /> (1) 100 to 700 mg/L of iron when ferrous sulfate alone is activator. <br /> (2) Same iron concentration as option 1 but also with either an ethylenediamine <br /> tetracetic acid (EDTA) or sodium citrate chelant concentration in the range of <br /> 523 to 7322 mg/L <br /> (3) 0. 14 to 42.8 gams/l, of hydrogen peroxide <br /> (4) Concentrations and quantities of bases such as sodium hydroxide, potassium <br /> hydroxide, and sodium carbonate, as determined by a site-specific titration of <br /> the groundwater, to raise its pH into the range of 10 to 12 <br /> Dosage: <br /> It is recommended that the dosage and details of a Klozur TM application be determined <br /> on a site-specific basis, but for information and planning purposes, the following rules- <br /> of-thumb may be helpful: <br /> • As recommended by FMC, typically 10 to 20% concentration, although <br /> solutions up to 40% may be formulated. The solubility of sodium persulfate <br /> at 25° C is 73% by weight. <br /> • 1 to 20 grams of Kloz1. <br /> ur rm persulfate per liter groundwater 1 to 20 grams of <br /> ozur persu fie pkilogram of soil <br /> • Delivery Methods: Injection using Geoprobe rods (200-600 psi) or 2-inch <br /> diameter well casings (40 psi) . <br /> Based on the high clay content of the soils and recommendations from FMC, AA&A <br /> recommends performing a bench test with the iron EDTA and sodium hydroxide. <br /> Chemical processes at work: FMC indicates that Klozur TM persulfate destroys <br /> contaminants both by direct oxidation and by free radical mechanisms involving sulfate <br /> radicals. It is also indicated that these radicals last longer (a matter of weeks to months) <br /> in the subsurface than do hydroxyl radicals. <br /> Stoichiometry: <br /> FMC indicates that a stoichiometric ratio for radical destruction is rather difficult to <br /> present, but that a ratio for direct oxidation can be shown by example for the complete <br /> mineralization of benzene. The ratio is 15 moles of sodium persulfate [Na2S208] at 238 <br /> grams per mole, to 1 mole of benzene [C6116] at 78 grams per mole. On a weight basis, <br /> 5 <br />