Prevent Mercury Loss During Transport and Storage

Use Siltek Surface Treatment on Steel Components

By Gary Barone, Manager, Restek Performance Coatings
  • Rugged—withstands temperatures up to 400°C.
  • Meets system inertness requirements.
  • Eliminates costly retests.

As concerns grow over mercury in the environment, new regulations have been developed to measure, and eventually reduce, mercury emissions from coal-fired electric utilities. For example, the US EPA will require all electric utilities to measure mercury emissions starting on January 1, 2009. The most popular methods of sampling will be based on continuous mercury monitoring systems (CMMS) and sorbent tube samplers. To ensure quantitative storage and transfer, and accurate analysis, of the low levels of mercury in streams sampled from flue stacks, these sampling systems must be inert.

Siltek surface treatment has been used in a wide variety of applications in which an inert surface is of paramount importance. To measure the impact of Siltek treatment on adsorption of mercury during storage, we compared the performances of 304 grade stainless steel gas sampling cylinders (Swagelok, Solon OH) with and without Siltek treatment.

We filled each cylinder with 8µg/m3 of elemental mercury (approximately 1 part per billion) (Spectra Gases, Alpha NJ) and assessed the mercury concentration in each cylinder over time to determine changes in mercury concentration. Detection was achieved by direct interface gas sampling to an atomic adsorption detector. Sample pathway regulator and tubing were Siltek treated to ensure accurate transfer.

The data in Figure 1 demonstrate that Siltek treatment provides a stable surface for elemental mercury, and untreated stainless steel does not. Based on these results, we conclude that Siltek surface treatment for steel or stainless steel components and tubing in CMMS and sorbent tube mercury sampling systems will improve analytical reliability.


Figure 1   Siltek treated gas sampling cylinders show very good inertness toward mercury.

Thank You

Ted Neeme and Steve Mandel from Spectra Gases for their contributions to this work

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