Characterization of oil sands naphthenic acids treated with ultraviolet and microwave radiation by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry.

Rapid communications in mass spectrometry : RCM · 2010 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 6501

Study snapshot

PublicationRapid communications in mass spectrometry : RCM · 2010

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

Naphthenic acids (NAs) are concentrated in oil sand process water (OSPW) as a result of caustic oil sands extraction processes. There is considerable interest in methods for treatment of NAs in OSPW. Earlier work has shown that the combination of ultraviolet (UV) and microwave treatments in the laboratory was effective in reducing the concentration of classical NAs. Here we apply Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to further characterize NAs treated with (a) UV (254 nm) in the presence of TiO(2) catalyst; and/or (b) microwave irradiation (2.45 GHz). FT-ICR MS was used to characterize the NA fraction before and after treatment. Acidic oxygen-containing classes were most abundant in all samples whereas other heteroatomic classes were least abundant or not present in some samples. For example, the SO(2)-containing species were absent in UV- or combined UV- and microwave-treated samples. The O(2) class was dominant in all samples, indicative of NAs. However, samples treated with UV and microwave radiation have a lower relative abundance of other heteroatomic classes. We observed O(2), S(1)O(2), O(3), S(1)O(3), O(4), O(5), and O(6) classes, whereas the species with relatively high O(n) content, namely, the O(3), O(5), and O(6) classes, were present only in UV- and microwave-treated samples. The relatively high O(n) content is consistent with oxidation of the parent acids in treated samples. There may thus be potential implications for environmental forensics. For example, the monitoring of the ratio of SO(2):O(2) or tracking the relative abundances of O(2), O(3), O(4), O(5), and O(6) classes may provide insights for distinguishing naturally derived oil sands components from those that are process-related in aquatic environments.

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AI evidence extraction

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Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave · 2450 MHz

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

FT-ICR MS characterization showed acidic oxygen-containing classes were most abundant in all samples, with O2 dominant. SO2-containing species were absent in UV- or combined UV+microwave-treated samples, and UV+microwave-treated samples showed lower relative abundance of other heteroatomic classes. Higher O(n) classes (O3, O5, O6) were reported only in UV- and microwave-treated samples, consistent with oxidation of parent acids.

Outcomes measured

Chemical composition/class distribution of naphthenic acids (NA fraction) in oil sands process water assessed by negative ion electrospray FT-ICR MS
Presence/absence and relative abundance of heteroatomic classes (e.g., O2, O3, O4, O5, O6; S1O2; S1O3; SO2-containing species) after UV and/or microwave treatment

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "microwave",
    "source": "laboratory microwave irradiation (treatment)",
    "frequency_mhz": 2450,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Chemical composition/class distribution of naphthenic acids (NA fraction) in oil sands process water assessed by negative ion electrospray FT-ICR MS",
    "Presence/absence and relative abundance of heteroatomic classes (e.g., O2, O3, O4, O5, O6; S1O2; S1O3; SO2-containing species) after UV and/or microwave treatment"
  ],
  "main_findings": "FT-ICR MS characterization showed acidic oxygen-containing classes were most abundant in all samples, with O2 dominant. SO2-containing species were absent in UV- or combined UV+microwave-treated samples, and UV+microwave-treated samples showed lower relative abundance of other heteroatomic classes. Higher O(n) classes (O3, O5, O6) were reported only in UV- and microwave-treated samples, consistent with oxidation of parent acids.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "naphthenic acids",
    "oil sands process water",
    "ultraviolet (254 nm)",
    "TiO2 photocatalyst",
    "microwave irradiation",
    "2.45 GHz",
    "FT-ICR MS",
    "negative ion electrospray",
    "heteroatomic classes",
    "oxidation",
    "environmental forensics"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/rcm.4754
PubMed: 20941758

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