Substitution of PFOS for use in nondecorative hard chrome plating

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The laboratory experiments were carried out by IPU and the large scale
testing was carried out at a.h. nichro Haardchrom A/S. FORCE Technology
was responsible for the chromium emission measurement during the large
scale testing.
Main conclusions
The main conclusions of the project are:
A non-PFOS mist suppressant chemical alternative was found (at
large scale testing) to be useful as an alternative to PFOS. The
effectiveness, the durability, and the price level were similar to that of
PFOS. The non-PFOS alternative is an environmental improvement
as it is less persistent, less bioaccumulative, and less toxic than PFOS.
A non-fluorinated mist suppressant chemical alternative was found
and might be a promising substitute for PFOS. However, as
continuously addition of the mist suppressant is needed, the usefulness
of the alternative seems to be limited for automated hard chrome
processes and must be assessed in each case.
A physical alternative – in the form of PTFE coated balls – does not
seem to lower the chromium emissions from the chrome bath. Quite
the contrary, the chromium emissions seem to increase compared to
using no mist suppressant at all.
A physical alternative – in the form of a mesh or blanket solution –
could be suitable for large scale series plating of uniform products.
However, this kind of alternative was not investigated further in this
project.
Finally, the laboratory results of this project showed that the Cr 6+
emission can be reduced radically by avoiding air convection. This
indicates that large scale tests of a physical method that prevents air
convection could turn out to be an alternative to PFOS. Such method
would be a suitable alternative to PFOS in mass production systems.
However, in plating system for frequently varying productions, it will
be more difficult to establish a closed system because of the flexibility
required to such systems. However, this alternative solution was not
investigated further in this project, but would be a very interesting
solution to investigate further.
Project results
Survey of the Danish and global use of PFOS in the chrome plating industry
A survey of the Danish use of PFOS in the chrome plating industry showed
that the annually use of PFOS in the Danish chrome plating industry is
between 10 to 28 kg (calculated as pure PFOS). This number was found by
contact to the Danish hard chrome platers and suppliers of PFOS as mist
suppressants to the Danish market.
The global use of PFOS in the chrome plating industry was estimated to be
around 32 to 40.7 tons of PFOS (calculated as pure PFOS). This number
was derived by contact to various global suppliers of PFOS as well as an
Internet search after various sources to this kind of information. Most
literature does not distinguish between the amount of PFOS used for non-