1999 Progress Report: Destruction of PCBs, CAHs, CFCs and Organic Nitro/Nitrate Wastes in Soils and Bulk with Ca/NH3 at Ambient TemperatureEPA Grant Number: R826180
Title: Destruction of PCBs, CAHs, CFCs and Organic Nitro/Nitrate Wastes in Soils and Bulk with Ca/NH3 at Ambient Temperature
Investigators: Pittman, Charles U.
Institution: Mississippi State University - Main Campus
EPA Project Officer: Lasat, Mitch
Project Period: February 1, 1998 through January 31, 2001 (Extended to January 31, 2002)
Project Period Covered by this Report: February 1, 1999 through January 31, 2000
Project Amount: $317,027
RFA: Exploratory Research - Environmental Chemistry (1997) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management , Air , Engineering and Environmental Chemistry
Objective:The major objective is to develop basic knowledge on the use of solvated electron chemistry for possible use as a single, multifunctional, portable technology applicable to both onsite in situ and onsite ex situ destruction of PCBs, CAHs, CFCs, munition/explosive residues, discarded propellants, and chemical warfare agents. The immediate objectives include the complete dechlorination of CAHs in Na/NH3 and Ca/NH3 in the presence of increasing quantities of water and learning if the reaction of solvated electron with water competes with dechlorination. Another objective is the destruction (complete dechlorination) of PCBs and CAHs in a variety of wet soils. The key goal is to remediate PCB- and CAH-contaminated soils in the presence of water without excessive consumption of Na or Ca via onsite slurrying of contaminated soil in Na/NH3 or Ca/NH3. Similar reductions of CFCs and nitro compounds?both neat and in soils?are being studied.
Progress Summary:We have demonstrated that soils contaminated with CCl4, CH3Cl3, 1-chlorooctane, and tetrachloroethylene can be readily decontaminated by slurry treatments with Na/NH3. Remarkably, this treatment is successful even when the soils are wet. The amount of Na consumed per chlorine that is mineralized in these treatments has been determined as a function of the concentration of contaminant present. Thus, Na consumptions per chlorine removed have been obtained for contaminant levels ranging from 5,000 ppm to levels of 10-50 ppm and on to below 1 ppm in some cases. The treatments can reduce contaminant levels to sub-ppm levels in sandy, organic, and clay soils and sludges. Environmental soil and sludge samples from a number of contaminated sites have been successfully treated in laboratory scale reactors.
The sodium required to completely dehalogenate a large series of chloro-aromatic, chlorinated phenolic, and chlorinated aliphatic molecules in dry NH3 and in NH3 containing 5, 20, and 50 mole equivalents of H2O per mole of substrate was determined. The sodium consumption increased as the water concentration increased, but the overall increases were modest, leaving the entire process economically feasible.
Laboratory treatments of PCB-contaminated soils with Na/NH3 and Ca/NH3 were successful on soils from Harrisburg, PA; Los Alamos, NM; New York, NY; and Monroe, LA. The PCB levels of the treated soils were below 1 ppm. Dioxin- and PCB-contaminated sludge from New Bedford Harbor were treated to sub-ppm levels with Na/NH3. Oils, highly contaminated with PCBs, were successfully remediated from 100,000 ppm levels to below 1 ppm with Na/NH3. Dioxin-contaminated waste oil from Stockton CA, was remediated from 418,500 ppt (dioxins) and 14,120 ppt (furans) to 2.3 ppt and 1.3 ppt, respectively, using Na/NH3. Decontamination of pesticides (DDT, DDE, and Dieldrin) in soils from Hawaii and Virginia were accompleded to below detectable levels. Finally, progress in decontaminating polynuclear aromatic hydrocarbons (PAHs) and explosives waste in soils (HMX, RDH, 1,2DNB) was made.
Future Activities:More work on aliphatic and aromatic nitro compounds will be performed to see the Na consumptions required for various structures. This should include model compound and soil work. Studies of defluorination (model compounds) and selective defluorination in the presence of other halogens such as chlorine (model compounds) will be conducted. Higher boiling CFCs are candidates for study. Because C-F bonds are hard to break, developing rapid defluorination methods is important. Further work on remediating metal ions, metals, chemical warfare simulants, and PAHs is needed and will be done as time permits.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 22 publications||8 publications in selected types||All 5 journal articles|
||Sun GR, He JB, Zhu HJ, Pittman CU. Cleavage of arylalkylsilanes by sodium amide in liquid ammonia. Synlett. 2000;(5):619-622.||
||Sun GR, He JB, Pittman CU Jr. Destruction of halogenated hydrocarbons with solvated electrons in the presence of water. Chemosphere 2000;41(6):907-916.||