Articles - Leather Technology Magazine Nº74
Formation of hexavalent chromium in
leather associated to chromium supply
and fat liquoring
Authors: Wagner F. Fuck, Mariliz Gutterres
Universidad Federal de Rio Grande do Sul, Chemical
Engineering Department, Laboratory for Leather and
Environmental Studies (LACUORO)
R. Eng. Luis Englert, s/n. Campus Central. CEP: 90040-
040 - Porto Alegre - RS - BRAZIL,
e-mail: mariliz@enq.ufrgs.br |
Formation of hexavalent chromium in
leather associated to chromium supply
and fat liquoring
Key words: hexavalent chromium, chrome tanning, fat
liquoring, rechroming
ABSTRACT
The growing importance of environmental
concepts and consumers’ awareness of the products being
used are requiring industries and service companies to
adopt a new posture. Given the hazardous or toxic content
of the substances that may be used in manufacturing
processes, it has become necessary to deepen research on
the subject and achieve their technical enhancement. In
this context, discussions have emerged regarding the use
of chromium as a basic constituent in leather, since it can
be oxidized from the trivalent to the hexavalent state with
carcinogenic potential and accumulate in the human body.
This paper contains a study of the influence of the amount
of chrome supplied in leather and the type of fat liquors -
both under normal conditions and after accelerated aging
- over chrome oxidation. In fat-liquored leathers, which
have not undergone an aging process, the presence of
hexavalent chromium was found to be below the detection
limit in all cases. Aging caused the formation of hexavalent
chromium. Sulfited and fish fat liquors showed higher
levels of hexavalent chromium formation in aged leather
samples, but not in synthetic fat liquor. The concentration
of hexavalent chromium did not show significant variations
on account of higher chrome supply in tanning, but it
increased in chrome retanning.
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