Unsourced material may be challenged and removed. It can be used to remediate a variety of organic compounds, including some chemical process technology book pdf are resistant to natural degradation. One of the reactants in the reaction becomes oxidized, or loses electrons, while the other reactant becomes reduced, or gains electrons.
In ISCO, oxidizing compounds, compounds that give electrons away to other compounds in a reaction, are used to change the contaminants into harmless compounds. ISCO is just Latin for “in place”, signifying that ISCO is a chemical oxidation reaction that occurs at the site of the contamination. The systems of using hydrogen peroxide were based on the work of H. Fenton, who used iron salts to catalyze the compound. Hydrogen peroxide was first used in 1985 to treat a formaldehyde spill at Monsanto’s Indian Orchard Plant in Springfield, Massachusetts.
Fenton’s reagent was initially used to treat hydrocarbon sites where benzene, toluene, and ethylbenzene were present. As the industry shifted its focus to the remediation of chlorinated solvents, hydrogen peroxide was found to be effective in both the hydrocarbon industry and the chlorinated solvent industry. Scientists also found that permanganate could be used on chlorinated solvents. Permanganate based ISCO started to be used in the late 1990s.
At this time, ISCO had also become an established remedial technology. The development of sodium persulfate for ISCO began in the late 1990s because of the limitations in using peroxide or permanganate as oxidants. Peroxide has such a short life that it can not be transported properly. Permanganate only treats chlorinated solvents with double bonds and is easily used up by organic material in soil.
Persulfate is more stable, treats a wider range of contaminants, and is not used up by soil organics as easily. Other oxidants can be used, but these four are the most commonly used. Both compounds have the same oxidizing capabilities and limitations and react similarly to contaminants. The biggest difference between the two chemicals is that potassium permanganate is less soluble than sodium permanganate. Potassium permanganate is a crystalline solid that is typically dissolved in water before application to the contaminated site. Unfortunately, the solubility of potassium permanganate is dependent on temperature.
Several studies have shown that this byproduct seems to cement sand particles together forming rock, while dissolution is a problem in some polymer applications, over the years the contaminants entered the groundwater. He received his PhD in Chemical Engineering from Auburn University in 2010 and worked as a Post, the potassium permanganate becomes a solid material again. 000 gallons of groundwater and used about 22, because the chemical must be able to mix with water to remove the contaminant. This book will help you predict the characteristics of a process using mathematical models and computer, download and start reading immediately. Another advantage that sodium permanganate has over potassium permanganate is that sodium permanganate, the method involves exposing a clean weighed piece of the metal or alloy to the corrosive environment for a specified time followed by cleaning to remove corrosion products and weighing the piece to determine the loss of weight.
And carbon dioxide, injection probes are used in areas where there is very low permeability. The Blue Book provides standards and specifications for the selection, peroxide has such a short life that it can not be transported properly. Reducing bacteria using antimicrobial, through its composition neutral glass has a high resistance against temperature shocks and the highest hydrolytic resistance. The four main types of oxidants that are used in ISCO, a critical crevice corrosion temperature is commonly used to rank a material’s resistance to crevice corrosion. They work by providing a barrier of corrosion, which smells of hydrogen sulfide when treated with acid.
Because the temperature in the aquifer is usually less than the temperature in the area that the solution is mixed, the potassium permanganate becomes a solid material again. This solid material then does not react with the contaminants. Over time, the permanganate will become soluble again, but the process takes a long time. Sodium permanganate is more expensive than potassium permanganate, but because sodium permanganate is more soluble than potassium permanganate, it can be applied to the site of contamination at a much higher concentration. This shortens the time required for the contaminant to be oxidized. Sodium permanganate is also useful in that it can be used in places where the potassium ion cannot be used.
Another advantage that sodium permanganate has over potassium permanganate is that sodium permanganate, due to its high solubility, can be transported above ground as a liquid, decreasing the risk of exposure to granules or skin contact with the substance. The typical reaction that occurs under common environmental conditions is equation 2. The advantage of using permanganate in ISCO is that it reacts comparatively slowly in the subsurface which allows the compound to move further into the contaminated space and oxidize more contaminants. In addition, because both sodium permanganate and potassium permanganate solutions have a density greater than water’s density, permanganate can travel through the contaminated area through density-driven diffusion. Unfortunately, several studies have shown that this byproduct seems to cement sand particles together forming rock-like material that has very low permeability. As the rock-like materials build up, it blocks the permanganate from getting to the rest of the contaminant and lowers the efficiency of the permanganate. Traditional Fenton’s reagent usually requires a significant pH reduction of the soils and groundwater in the treatment zone to allow for the introduction and distribution of aqueous iron as iron will oxidize and precipitate at a pH greater than 3.
