You are here:
EFFECT OF PITTING CORROSION PROMOTERS ON THE TREATMENT OF WATERS CONTAMINATED WITH A NITROAROMATIC COMPOUNDS USING INTEGRATED REDUCTIVE/OXIDATIVE PROCESSES
Impact/Purpose:
ed formed of corrosion Which causes continuous metal oxidation via the creation of acidic micro-environments within the metallic species. Steady metal oxidation in this case, translates into the continuous generation of electrons that react with the adsorbed species on the metal surface. It is also proposed that bi-metallic species of iron/manganese could be synthesized with the capability to reduce and oxidize nitro and amino aromatic compounds. This type of metallic species could transformed NACs into non-toxic low molecular weight organic and inorganic compounds in one single treatment step, reducing significantly capital and operating treatment costs. ed formed of corrosion Which causes continuous metal oxidation via the creation of acidic micro-environments within the metallic species. Steady metal oxidation in this case, translates into the continuous generation of electrons that react with the adsorbed species on the metal surface. It is also proposed that bi-metallic species of iron/manganese could be synthesized with the capability to reduce and oxidize nitro and amino aromatic compounds. This type of metallic species could transformed NACs into non-toxic low molecular weight organic and inorganic compounds in one single treatment step, reducing significantly capital and operating treatment costs.
Contamination with nitroaromatic compounds (NACs) such as 2.4,6-trinitrotoluene (TNT), 2,4 dinitrotoluene, 2,6-dinitrotoluene, and nitrobenzene is prevalent around United States Department of Defense (DoD) ammunition production facilities employed to support military activities. Past improper wastewater disposal techniques, such as direct discharges into drainage ditches, local streams, and settling lagoons have created soil, sediment, surface water, and groundwater contamination around these manufacturing facilities. Gulf Coast States such as Alabama, Louisiana, and Texas have ammunition production facilities listed on the Superfund National Priority List (NPL). Surface and groundwater contaminants of concern at these sites include TNT, 2,4 dinitrotoluene, 2,6-dinitrotoluene, nitrobenzene, and other nitroaromatic explosives. Treatment techniques, such as advanced oxidation processes (AOPs), which rely on the strong oxidation capability of the hydroxyl radical ( OH· ), as well as anaerobic and aerobic biodegradation, have been investigated for the treatment of NACs contaminated waters. However, these techniques are not cost effective as stand-alone treatment processes due to the generation of recalcitrant and/or regulated reaction by-products.
It is proposed that the integration of zero-valent metallic (ZVM) species followed by AOPs can mineralize and/or transformed NACs into low molecular weight non-toxic compounds. The aromatic amines formed during the reduction reaction with zero-valent iron are more oxidizable than the parent compound. In order to minimize the deactivation of the metal caused by the adsorbed amine by-products, it is proposed to add pitting corrosion promoters (for example, NaCl) to the contaminated water prior to the ZVM step. Pitting is a localiz
Description:
All the reaction mechanisms developed during the proposed research activities will provide essential information during risk assessment and evaluation of remediation strategies of NACs contamination. The concept of integrated reductive/oxidative technologies. experimental procedures, rate expressions, and design calculations that will be evaluated and developed during the proposed research could be applied for the treatment of waters containing organic pollutants with structural, chemical, and physical properties similar to NACs. Such as azo dyes and some pesticides. Additionally, the novel concept of hyphenated technologies and bimetallic reduction agents could potentially be applied for the treatment of other recalcitrant organic contaminants such as polycyclic aromatic hydrocarbons and polychlorinated biphenyls. These contaminants are included in the Environmental Protection Agency list of priority pollutants.