Biodegradability of wastewater from enzymatic soaking and unhairing processes in leather Manufacture / Qiang He in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 6 (06/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 6 (06/2006) . - p. 217-222 Titre : Biodegradability of wastewater from enzymatic soaking and unhairing processes in leather Manufacture Type de document : texte imprimé Auteurs : Qiang He, Auteur ; Bi Shi, Auteur ; Danhong Sun, Auteur ; Kai Yao, Auteur Année de publication : 2006 Article en page(s) : p. 217-222 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Enzyme-treating processes in leather making are usually considered as 'clean technology' in terms of the reduction of pollutants in wastewater. The objective of this study is to investigate the biodegradability of the wastewater collected from enzyme-treating processes. It is of great significance to characterize the pollution properties of this kind of wastewater, and to provide a reference for the biological treatment of such wastewater in effluent treating yard of tannery. The research was typified by enzymatic soaking and unhairing (ESU) processes which are encouraged to be used in leather manufacture for reducing environmental impact. The biodegradability of ESU wastewater before and after settling treatment was investigated, in comparison with that of wastewater collected from conventional soaking and unhairing (CSU) processes. It was found that ESU wastewater had better biodegradability than CSU wastewater. The biodegradation extent of ESU and CSU wastewaters reached 58.5% and 37.7% respectively in 20 days of naturally biodegrading process. Moreover, it was found that, in the presence of activated sludge, 65.5% of the total oxygen-consuming materials in ESU wastewater is biodegradable, while the value of CSU wastewater is 58.2%. En ligne : https://drive.google.com/file/d/1jZAGItlsni_ZwfJIUXM0-ZesKVySf49O/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3998 [article]

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Environmental impact evaluation of typical beamhouse processes in leather manufacture based on wastewater settleability / Qiang He in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 12 (12/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 12 (12/2005) . - p. 473-480 Titre : Environmental impact evaluation of typical beamhouse processes in leather manufacture based on wastewater settleability Type de document : texte imprimé Auteurs : Qiang He, Auteur ; Bi Shi, Auteur ; Danhong Sun, Auteur ; Kai Yao, Auteur Année de publication : 2005 Article en page(s) : p. 473-480 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The traditional leather industry is far from sustainable. Therefore, many new leather-making processes, so called 'cleaner technologies', have been proposed to reduce the levels of pollutant emission. The objective of this study is to make an environmental impact evaluation of such processes not only based on the quantity of wastes generated but also on the wastewater treatability. This paper is mainly concerned with the settleability of wastewater. Such an evaluation might be of great significance due to the enormous amount of wastewater and increased treatment costs. The research is typified by enzyme assisted soaking and unhairing (ESU) processes that are encouraged in beamhouse processes for protecting the environment. The chemical sedimentation behavior of ESU wastewater and the wastewater generated by conventional soaking and unhairing (CSU) processes are described and compared with each other. It was found that ESU wastewater showed better sedimentation property than CSU wastewater, indicating that the enzyme assisted soaking and unhairing processes have environmental friendliness in terms of wastewater settleability. En ligne : https://drive.google.com/file/d/1_0dJjyfAM62grW4AZU5geeIACbJLIbEa/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4048 [article]

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Evaluation of environmental impact of typical leather chemicals. Part 2 : Biodegradability of organic tanning agents by activated sludge / Danhong Sun in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 2 (03-04/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 2 (03-04/2008) . - p. 59-64 Titre : Evaluation of environmental impact of typical leather chemicals. Part 2 : Biodegradability of organic tanning agents by activated sludge Type de document : texte imprimé Auteurs : Danhong Sun, Auteur ; Qiang He, Auteur ; Zhang Wenjun, Auteur ; Yulu Wang, Auteur ; Bi Shi, Auteur Année de publication : 2008 Article en page(s) : p. 59-64 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acrylique Agents de tannage Aldéhydes Un aldéhyde est un composé organique, faisant partie de la famille des composés carbonylés, dont l'un des atomes de carbone primaire (relié au plus à 1 atome de carbone) de la chaîne carbonée porte un groupement carbonyle. L'aldéhyde le plus simple est le formaldéhyde (ou méthanal), aussi appelé formol lorsqu'il est en solution aqueuse. Un aldéhyde dérive formellement d'un alcool primaire (oxydation) dont le groupement hydroxyde -OH est en bout de chaîne et se forme suite à l'enlèvement de deux atomes H d'où le nom "alcool déshydrogéné" ou aldéhyde. Biodégradation Boues résiduaires -- Analyse Composés aromatiques Composés organiques Cuirs et peaux -- Industrie -- Aspect de l'environnement Environnement -- Etudes d'impact Evaluation Syntans Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The biodegradability of typical organic tanning agents, including aromatic syntans, aldehydic tanning agents and acrylic tanning agents, were investigated. The results showed that the biodegradation behaviours of these leather chemicals are closely associated with their chemical structures, molecular weights and compositions. Therefore, different organic tanning agents might result in different environmental impacts even though they belong to the same type of tanning agent. The four aromatic syntans tested exhibited low biodegradability in general. Among them, a phenol-based syntan was not biodegradable and the phenol-sulphone based syntan produced a strong inhibitory effect on respiration of activated sludge. Comparatively, the naphthalene-based syntan was somewhat easier to biodegrade than other aromatic syntans. In the cases of aldehydic tanning agents, both formaldehyde and glutaraldehyde were not biodegradable and were toxic to organisms in activated sludge. Thus, they are potential inhibitors to biodegradation of other organic compounds in wastewater. However, an aliphatic aldehydic tanning agent was biodegradable and showed no toxicity to microorganisms in activated sludge. As for acrylic tanning agents, results indicated that commercial anionic products do not have any negative effect on biodegradation activity of activated sludge but they themselves were hardly biodegraded. Whereas, cationic acrylic tanning agents have the potential to inhibit the activated sludge process when presented at a high concentration. Note de contenu : - Biodegradability of aromatic syntans - Biodegradability of aldehydic tanning agents - Biodegradability of acrylic tanning agents - Table 1 : The types and main properties of organic tanning agents used in experiments - Table 2 : BOD5 /COD values of aromatic syntans - Table 3 : BOD5 /COD values of aldehydic tanning agents En ligne : https://drive.google.com/file/d/1O2b7myavpoCSbVBi0--SckW-RKh98-ca/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38931 [article]

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Evaluation of environmental impact of typical leather chemicals. Part 3 : Biodegradability of vegetable tannin extracts by activated sludge / Qiang He in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 103-106 Titre : Evaluation of environmental impact of typical leather chemicals. Part 3 : Biodegradability of vegetable tannin extracts by activated sludge Type de document : texte imprimé Auteurs : Qiang He, Auteur ; Danhong Sun, Auteur ; Xin Liu, Auteur ; Lin Wei, Auteur ; Bi Shi, Auteur Année de publication : 2008 Article en page(s) : p. 103-106 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biodégradation Boues résiduaires -- Analyse Cuirs et peaux -- Industrie -- Aspect de l'environnement Déchets industriels -- Elimination Environnement -- Etudes d'impact Tanins végétaux Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The short-term (5 day) and long-term (30 day) biodegradation behaviours of black wattle, bayberry, valonia and chestnut tannin extracts were systematically investigated in this paper. The results indicated that all of these four vegetable tannin extracts are biodegradable although they might retard the biodegradation process to some extent owing to the inhibitory effect of tannins on the activated sludge process. Short-term biodegradabilities of the four tannin extracts were concentration-dependent. These tannin extracts could be effectively biodegraded in 5 days at concentrations of 0.25g/L, but the biodegradation process was retarded remarkably when the concentrations were increased to 5.00g/L. In general, short-term biodegradabilities of the four tannin extracts follow the sequence of valonia tannin>chestnut tannin>bayberry tannin>wattle tannin, implying that the hydrolysable tannins are easier to biodegrade than the condensed tannins. The results of long-term biodegradation showed that all of the four vegetable tannin extracts can be completely biodegraded by prolonging the activated sludge process, even if they are present at high concentration. Therefore, the encouraging findings in this research suggest that vegetable tannin extracts are environmentally friendly leather chemicals. Note de contenu : - BOD5/COD values of vegetable tannin extracts - Respiration of activatedslud ge in the presence of vegetable tannin extracts - COD removals of vegetable tannin extracts by the activatedslud ge process - COD removals (%) of vegetable tannin extracts at different concentrations - Table 1 : Type andtannin content of vegetable tannin extracts tested in experiments - Table 2 : BOD5 /COD values of vegetable tannin extracts at different concentrations En ligne : https://drive.google.com/file/d/1rkdcAB3YoMjEm3urqqTf-HjnXnzkK-x3/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38954 [article]

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Further investigations of oxidative unhairing using hydrogen peroxide / Bi Shi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 5 (05/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 5 (05/2003) . - p. 185-192 Titre : Further investigations of oxidative unhairing using hydrogen peroxide Type de document : texte imprimé Auteurs : Bi Shi, Auteur ; Xingfang Lu, Auteur ; Danhong Sun, Auteur Année de publication : 2003 Article en page(s) : p. 185-192 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The research includes details of hair removal from hide and the influence of hydrogen peroxide on hide/collagen during unhairing process. The results showed that destruction of hair was led by cooperative effect of hydrogen peroxide and sodium hydroxide. The dissolution of hair first happened at hair root, which favors implementation of hair saving system. It was also found that the oxidative effect of H2O2 causes slight protection function of collagen in alkaline medium ( probably, due to cross-linking reaction of collagen induced by H2O2), which is one of the reasons leading to higher tensile strength and lower elongation rate of resultant leather. Isoelectric point of the hide unhaired with H2O2 was lower than that using conventional Na2S unhairing process, due to that more carboxyl or anionic groups were probably derived. Therefore, the chrome tanned leather employing H2O2 unhairing process exhibited higher Cr2O3 content. Based on these observations, the optimal conditions for undertaking H2O2 unhairing, including hair dissolution and hair recovery processes, were presented. En ligne : https://drive.google.com/file/d/1YYxeEr5GHZge4SAz8ObHIq79u9iPWkDk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4121 [article]

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Oxidative dechroming of leather shavings under ultrasound / Danhong Sun in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 3 (05-06/2003)  

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