The sulphide challenge / Jens Fennen in LEATHER INTERNATIONAL, Vol. 215, N° 4836 (11-12/2013)  

[article]  inLEATHER INTERNATIONAL > Vol. 215, N° 4836 (11-12/2013) . - p. 25-27 Titre : The sulphide challenge Type de document : texte imprimé Auteurs : Jens Fennen, Auteur ; Daniel Herta, Auteur ; Jan-Tiest Pelckmans, Auteur ; Jürgen Christner, Auteur Année de publication : 2013 Article en page(s) : p. 25-27 Langues : Anglais (eng) Catégories : Atmosphère -- Pollution Cuirs et peaux -- Industrie -- Aspect de l'environnement Industrie -- Pollution -- Lutte contre Odeurs -- Lutte contre Sulfure d'hydrogène Sulfures Travail de rivière (cuir) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanneries are often associated with the characteristic and obnoxious "sulfide smell", which is in fact caused by low concentrations of sulfhydric gas, also known as hydrogen sulfide. Levels as low as 0.2 ppm of H2S are already unpleasant for humans and a concentration of 20 ppm is unbearable. As a result, tanneries might be forced to close down beamhouse operations or are forced to re-locate away from populated areas. As beamhouse and tanning are often done in the same facility, smell is actually the lesser problem. Through human errors, this always holds the danger of mixing acidic floats with the sulfide containing beamhouse float and releasing higher amounts of H2S. At a level of 500 ppm all olfactory receptors are blocked and the gas, therefore, becomes unnoticeable and an exposure for 30 min results in a life threatening intoxication. At a concentration of 5,000 ppm (0.5%), the toxicity is so pronounced that a single breath is enough to cause immediate death within seconds. Despite all these problems and risks, sulphide has been the preferred chemical for unhairing for more than a century. This can be attributed to unavailable workable alternatives: the use of organic sulphides has shown to be practicable but not really accepted due to the extra costs involved. Unhairing solely by proteolytic and keratolytic enzymes has been tried over and over again but for the lack of selectiveness was difficult in practice to control. A lot of work has also been invested in oxidative unhairing, but until today it is very limited in its use as it is hard to get consistent results. Note de contenu : - The unhairing process - Soaking is a key factor for efficient unhairing - Low sulphide enzymatic assisted unhairing - A low sulphide, low time hair safe process En ligne : https://drive.google.com/file/d/1LagW96JfoonNNG_1joIQYOLE8LsGPvj2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=20450 [article]

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