Effect of soil pH on thermally enhanced desorption of m-xylene by zero-valent iron particles under an electromagnetic field.

Journal of hazardous materials · 2023 · Benefit · Insufficient evidence

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BenefitInsufficient evidencePaper 5725

Study snapshot

PublicationJournal of hazardous materials · 2023

Study typeother

Reported directionBenefit

Evidence ratingInsufficient

Abstract

This study, for the first time, evaluates a novel method for the desorption of contaminants from soil that uses the heat generated by zero-valent iron (ZVI) under low-frequency electromagnetic fields (EMF), and elucidates the specific effects of soil pH upon the process. It was found that the temperature of soil mixed with ZVI could reach up to ∼60 °C within 20 min under the applied EMF, and after 60 min the residual fraction of m-xylene in soil decreased by 86.4% compared to no-ZVI soil. The most efficient desorption of m-xylene occurred at a soil of pH 5. Desorption was related to the net heating capacity of the ZVI particles, which was defined by pH-dependent formation of surface corrosion products. The preservation of metal iron and formation of Fe(II) species was favored for heat generation. Soil pH also affected m-xylene retention and the local thermal conduction from ZVI to m-xylene by regulating the surface properties of fulvic acid and ZVI. This study provides valuable information regarding the impact of pH on the thermal desorption of soil contaminants by ZVI coupled with EMF and illustrates the potential of the method in the remediation of contaminated sites.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionbenefit

PopulationNot supplied

Sample sizeNot supplied

ExposureELF · 20 min; 60 min

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Soil mixed with zero-valent iron (ZVI) reached approximately 60°C within 20 minutes under the applied low-frequency EMF. After 60 minutes, the residual fraction of m-xylene in soil decreased by 86.4% compared with no-ZVI soil, with the most efficient desorption at soil pH 5. Desorption was linked to pH-dependent ZVI surface corrosion products affecting heating capacity and thermal conduction to m-xylene.

Outcomes measured

Soil temperature increase with ZVI under low-frequency EMF
Residual fraction / desorption of m-xylene from soil
Effect of soil pH on desorption efficiency
Formation of ZVI corrosion products (Fe(II) species) related to heat generation
m-xylene retention and local thermal conduction influenced by pH via fulvic acid/ZVI surface properties

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "20 min; 60 min"
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Soil temperature increase with ZVI under low-frequency EMF",
    "Residual fraction / desorption of m-xylene from soil",
    "Effect of soil pH on desorption efficiency",
    "Formation of ZVI corrosion products (Fe(II) species) related to heat generation",
    "m-xylene retention and local thermal conduction influenced by pH via fulvic acid/ZVI surface properties"
  ],
  "main_findings": "Soil mixed with zero-valent iron (ZVI) reached approximately 60°C within 20 minutes under the applied low-frequency EMF. After 60 minutes, the residual fraction of m-xylene in soil decreased by 86.4% compared with no-ZVI soil, with the most efficient desorption at soil pH 5. Desorption was linked to pH-dependent ZVI surface corrosion products affecting heating capacity and thermal conduction to m-xylene.",
  "effect_direction": "benefit",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "low-frequency electromagnetic field",
    "EMF",
    "zero-valent iron",
    "ZVI",
    "soil remediation",
    "thermal desorption",
    "m-xylene",
    "soil pH",
    "corrosion products",
    "Fe(II)",
    "fulvic acid"
  ],
  "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: 10.1016/j.jhazmat.2022.130019
PubMed: 36166910

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