# Catalytic hydrodechlorination of PCDD/Fs from condensed water with Pd/γ-Al2O3.
> Pd/γ-Al2O3触媒を用いた凝縮水中PCDD/Fsの接触水素脱塩素化


## Abstract

A continuous pyrolysis system equipped with air pollution control devices was developed for remediating soil with elevated PCDD/F concentrations. The quench tower generated condensed water containing 16–44 ng I-TEQ/L of PCDD/Fs, requiring further processing. Activated carbon adsorption at a liquid-to-solid ratio of 3:1 met regulatory discharge limits but involved high material costs. Catalytic hydrodechlorination using Pd/Al2O3 was therefore evaluated. Without a reducing agent, 53.21% mass removal was achieved over 180 minutes; adding 5% methanol as a hydrogen donor raised this to 71.86%. When the condensed water was pre-aerated with molecular hydrogen gas prior to palladium-catalyzed hydrodechlorination, removal efficiency reached 97.34% within the same timeframe, demonstrating the superior performance of molecular hydrogen compared with conventional hydrogen donors in this catalytic dechlorination process.

### Mechanism

Molecular hydrogen adsorbed on palladium catalyst sites reductively cleaves carbon-chlorine bonds in PCDD/Fs, enabling efficient dechlorination that surpasses methanol-based hydrogen donor systems.

## Bibliographic

- **Authors**: Liu M, Chang SH, Chang MB
- **Journal**: Chemosphere
- **Year**: 2016
- **PMID**: [27088535](https://pubmed.ncbi.nlm.nih.gov/27088535/)
- **DOI**: [10.1016/j.chemosphere.2016.03.135](https://doi.org/10.1016/j.chemosphere.2016.03.135)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: positive

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 27088535. https://h2-papers.org/en/papers/27088535
> **Source**: PubMed PMID [27088535](https://pubmed.ncbi.nlm.nih.gov/27088535/)