Ammonia nitrogen in tannery wastewater : distribution, origin and prevention / Yanan Wang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 2 (02/2012)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVII, N° 2 (02/2012) . - p. 40-49 Titre : Ammonia nitrogen in tannery wastewater : distribution, origin and prevention Type de document : texte imprimé Auteurs : Yanan Wang, Auteur ; Yunhang Zeng, Auteur ; Xiaowei Chai, Auteur ; Xuepin Liao, Auteur ; Qiang He, Auteur ; Bi Shi, Auteur Année de publication : 2012 Article en page(s) : p. 40-49 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Eaux usées -- Analyse Eaux usées -- Teneur en azote ammoniacal Travail de rivière (cuir) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tannery wastewater usually contains a high content of ammonia nitrogen (NH3-N), which increases the difficulty of wastewater treatment. The objective of this work is to investigate the distribution of NH3-N in wastewaters from beamhouse processes and analyze the origin of NH3-N in each operation, so that the strategies that can reduce NH3-N at the origin could be suggested. Not surprisingly, the results demonstrate that NH3-N mainly concentrates in deliming and bating wastewaters due to the addition of ammonium salts in these two operations. This problem can be solved by using non-ammonia deliming and bating agents. A small quantity of NH3-N arises from washing and soaking processes because of decomposition of proteins by microorganisms. But the NH3-N in washing and soaking wastewaters may considerably increase when skins are badly preserved or the microorganisms in soaking float are not properly inhibited. Therefore, the effective antibacterial measures are important to diminish the production of NH3-N in beamhouse processes. As for unhairing/liming process, NH3-N in wastewater is mainly originated from hydrolysis of proteins, such as keratin and collagen, by strong alkali. Hair-saving unhairing and pelt swelling under milder conditions favor the decrease of NH3-N discharge. In fact, the amount of organic nitrogen released from washing, soaking and liming processes is much more than NH3-N. The experimental results indicate that the organic nitrogen mainly results from non-collagen proteins and their hydrolysates. This means the discharge of organic nitrogen is difficult to be avoided, and it may constitute a threat to end-of-pipe treatment of NH3-N. Note de contenu : - EXPERIMENTAL : Materials - Determination of NH3-N in beamhouse wastewaters - Determination of NH3- content in leather chemicals - Effect of curing time on NH3-N concentration in washing wastewater - Effect of soaking time on NH3-N concentration in soaking wastewater - Analysis of origin of NH3-N in unhairing/liming wastewater - Effect of reliming time on NH3-N concentration in reliming wastewater - Determination of TN and hydroxyproline in beamhouse wastewaters - Analysis of origin of TN in unhairing/liming wastewater - Analysis of origin of TN in deliming wastewater - Analytical methods : Ammonia nitrogen - Total nitrogen - Hydroxyproline - RESULTS AND DISCUSSION : Distribution of NH3-N in wastewaters of pig skin beamhouse processes - Distribution of NH3-N in wastewaters of cattle hide beamhouse processes - Origin of NH3-N in initial washing and soaking wastewaters - Origin of NH3-N in unhairing/liming wastewater - Origin of NH3-N in reliming wastewater - Relationship between TN and NH3-N in beamhouse wastewaters En ligne : https://drive.google.com/file/d/12alRCA2Lr5eBz6sPv3YF4X4vui_ZBxhV/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13569 [article]

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Determination of fatty spew on leather by BG-MS / Yanan Wang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 6 (06/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 6 (06/2011) . - p. 179-183 Titre : Determination of fatty spew on leather by BG-MS Type de document : texte imprimé Auteurs : Yanan Wang, Auteur ; Xuepin Liao, Auteur ; Qiang He, Auteur ; Bi Shi, Auteur Année de publication : 2011 Article en page(s) : p. 179-183 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acides gras Chromatographie en phase gazeuse Cuirs et peaux -- Analyse Esters méthyliques Produits de nourriture du cuir Spectrométrie de masse Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The composition of fatty spew on leather was determined by gas chromatography-mass spectrometry (GC-MS). Meanwhile, the volatile substances in the fogging test of leather were identified by GC-MS. With the combination of all the data obtained, it was found that the predominant components of fatty spew were palmitic acid methyl ester, oleic acid methyl ester and stearic acid methyl ester, and their relative content ratio is approximately 8 : 1 : 1. An interesting phenomenon was that no fatty acids are detected in fatty spew although they are commonly regarded as the origin of this defect. These facts strongly suggest that the fatty acid methyl esters existing in fatliquors are the main origin of fatty spew defect in leather, and also one of the probable contributions to fogging. En ligne : https://drive.google.com/file/d/1mOQWty7kBC3ZCOVw9QEGKzDCKlIoWnBS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11716 [article]

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