Free-radical oxidation of organic phosphonic acid salts in water using hydrogen peroxide, oxygen, and ultraviolet light

We indude in this review an assessment of the formation, environmental fate, and mammalian and ecotoxicity of CW agent degradation products relevant to environmental and occupational health.These parent CW agents indude several vesicants: sulfur mustards [undistilled sulfur mustard (H), sulfur mustard (HD), and an HD/agent T mixture (HT)]; nitrogen mustards [ethylbis(2-chloroethyl)amine (HN1), methylbis(2-chloroethyl)amine (HN2), tris(2-chloroethyl)amine (HN3)], and Lewisite; four nerve agents {O0ethyl S.[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), tabun (GA), sarin (GB), and soman (GD)}; and the blood agent cyanogen chloride. The degradation processes considered here include hydrolysis, microbial degradation, oxidation, and photolysis. We also briefly address decontamination but not combustion processes. Because CW agents are generally not considered very persistent, certain degradation products of significant persistence, even those that are not particularly toxic, may indicate previous CW agent presence or that degradation has occurred. Of those products for which there are data on both environmental fate and toxicity, only a few are both environmentally persistent and highly toxic. Major degradation products estimated to be of significant persistence (weeks to years) indude thiodiglycol for HD; Lewisite oxide for Lewisite; and ethyl methyl phosphonic acid, methyl phosphonic acid, and possibly S.(2-diisopropylaminoethyl) methylphosphonothioic acid (EA 2192) for VX. Methyl phosphonic acid is also the ultimate hydrolysis product of both GB and GD. The GB product, isopropyl methylphosphonic acid, and a dosely related contaminant of GB, diisopropyl methylphosphonate, are also persistent. Of all of these compounds, only Lewisite oxide and EA 2192 possess high mammalian toxicity. Unlike other CW agents, suifur mustard agents (e.g., HD) are somewhat persistent; therefore, sites or conditions involving potential HD contamination should include an evaluation of both the agent and thiodiglycol.

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“…MPA can be oxidized to phosphoric acid, carbon dioxide, and water in the presence of hydrogen peroxide, oxygen, and UV light (265). No (266).…”

Section: Gdmentioning

confidence: 99%

“…IMPA and MPA can be oxidized to phosphoric acid, carbon dioxide, and water in the presence of hydrogen peroxide, oxygen, and UV light (265). Mill and Gould (265) found no intermediates in the oxidation of MPA, but acetone, acetic acid, and MPA were formed in the oxidation of IMPA. (Table 15).…”

Section: Gamentioning

confidence: 99%

The sources, fate, and toxicity of chemical warfare agent degradation products.

Munro

Talmage

Griffin

et al. 1999

Environ Health Perspect

532

501

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“…EMPA is resistant to hydrolysis, but will slowly hydrolyze to MPA. MPA can be oxidized to phosphoric acid, carbon dioxide and water in the presence of hydrogen peroxide, oxygen, and ultraviolet light [42]. No intermediates were formed in the case of MPA under this sequence.…”

Section: Decontaminationmentioning

confidence: 90%

Chemical Warfare Agent Degradation and Decontamination

Talmage¹,

Watson²,

Hauschild³

et al. 2007

COC

117

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The decontamination of chemical warfare agents (CWA) from structures, environmental media, and even personnel has become an area of particular interest in recent years due to increased homeland security concerns. In addition to terrorist attacks, scenarios such as accidental releases of CWA from U.S. stockpile sites or from historic, buried munitions are also subjects for response planning. To facilitate rapid identification of practical and effective decontamination approaches, this paper reviews pathways of CWA degradation by natural means as well as those resulting from deliberately applied solutions and technologies; these pathways and technologies are compared and contrasted. We then review various technologies, both traditional and recent, with some emphasis on decontamination materials used for surfaces that are difficult to clean. Discussion is limited to the major threat CWA, namely sulfur mustard (HD, bis[2-chloroethyl]sulfide), VX (O-ethyl S-[2-diisopropylaminoethyl] methylphosphonothioate), and the Gseries nerve agents. The principal G-agents are GA (tabun, ethyl N,N-dimethylphosphoramidocyanidate), GB (sarin, isopropyl methylphosphonofluoridate), and GD (soman, pinacolyl methylphosphonofluoridate). The chemical decontamination pathways of each agent are outlined, with some discussion of intermediate and final degradation product toxicity. In all cases, and regardless of the CWA degradation pathway chosen for decontamination, it will be necessary to collect and analyze pertinent environmental samples during the treatment phase to confirm attainment of clearance levels.

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“…The kinetic constants increase because H 2 O 2 produces highly reactive hydroxyl radical HO when H 2 O 2 directly absorbs LP/UV light. The kinetic constants decrease because hydrogen peroxide combines hydroxyl radicals to form less reactive hydroperoxyl radicals (equation 1) [15]. Hydrogen peroxide has been found to consume hydroxyl radicals according to the following equations.…”

Section: Lp/uv Light Intensitymentioning

confidence: 99%

Hydrogen peroxide-assisted low pressure UV photodegradation of atrazine in aqueous solution

Li¹,

Gao²,

Wang³

et al. 2012

International Journal of Environmental Studies

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Aqueous solutions of atrazine (ATZ, 2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-triazine) were photolysed (λ = 254 nm) by low pressure UV/H 2 O 2 process (LP/UV/H 2 O 2 ) under a variety of parameters including hydrogen peroxide, the initial concentration of ATZ, pH, and humic acid. The results show that the most favourable reaction condition appears to be a moderate concentration of H 2 O 2 from 100 mg/L to 120 mg/L. The presence of humic acid in the solution has a negative impact on the LP/UV/H 2 O 2 treatment because of scavenging effects. Ninety percent of ATZ is destroyed in one hour under the optimum conditions. In this study, LP/UV/ H 2 O 2 treatment of ATZ yielded several organic by products which are identified, including DIA, DEA, OHDIA, OHDEA, DAA and OAAT. They are quantified over the range of treatment tested and the ATZ degradation scheme is proposed combined with by products information.

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Free-radical oxidation of organic phosphonic acid salts in water using hydrogen peroxide, oxygen, and ultraviolet light

Cited by 18 publications

References 7 publications

The sources, fate, and toxicity of chemical warfare agent degradation products.

The sources, fate, and toxicity of chemical warfare agent degradation products.

Chemical Warfare Agent Degradation and Decontamination

Hydrogen peroxide-assisted low pressure UV photodegradation of atrazine in aqueous solution

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