Cr(VI) Formation in leather during post-tanning processes / D. Chaudhuri in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 85, N° 6 (11-12/2001)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 85, N° 6 (11-12/2001) . - p. 211-216 Titre : Cr(VI) Formation in leather during post-tanning processes Type de document : texte imprimé Auteurs : D. Chaudhuri, Auteur ; S. K. Sarkar, Auteur Année de publication : 2001 Article en page(s) : p. 211-216 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ammoniac Analyse quantitative (chimie) Bicarbonate de sodium Cuir -- Teneur en chrome hexavalent Cuirs et peaux -- Analyse Déshydratation Neutralisation (chimie) Post-tannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Experiments have been conducted to examine the influence of three parameters, namely, degree of neutralisation. intensity of acidification towards the end of fatliquoring and drying condition, on the development of Cr(VI) in soft leathers such as utility gloving which require very strong deacidification. Chrome tanned cow hide pieces have been neutralised, fatliquored, dried and eventually analysed quantitatively for Cr(VI) using EN420, a colorimetric method based on diphenyl carazide (DPC). Experiments have also been carried out to identify the processing stages at which Cr(VI) can be detected in leather. In this case, samples of leather have been drawn during processing at the end of different unit operations, namely, neutralisation, fatliquoring and drying with or without sunlight and all these samples have been analysed for Cr(VI) immediately using the same analytical method. The results of all these experiments are presented here. The results show that a high degree of neutralisation when combined with total absence of acidification in the final stage of fatliquoring and sun-drying, results in leather containing large amounts of Cr(VI). Therefore, the results of the experiments conducted in the present study clearly indicate that coversion of Cr(Ill) to Cr(VI) takes place during processing of chrome tanned hide specially for soft leathers such as garment and utility gloving. Note de contenu : - Possible Sources of Cr(Vl) - Quantitative analysis of leather for Cr(Vl) - Experimental - Analytical methods - Limitations of the Work - Appendix 1 - Table 1 : Cr( Vl) content of leather neutralised with varying percentage of sodium bicarbonate - Table 2 : Influence of ammonia treatment on Cr(VI) level - Table 3 : Influence of a combined treatment of sodium bicarbonate and ammonia on Cr(VI) content of leather - Table 4 : Combined influence of end pH and degree of neutralisation on Cr(VI) level - Table 5 : Effect of sundrying on Cr(Vl) level in leather En ligne : https://drive.google.com/file/d/1TyR8jWoSKDAIavpNCkgruLbhW4nEk_TA/view?usp=drive [...] Format de la ressource électronique : pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40216 [article]

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