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Bioremediation of tannery effluents and chromium containing wastes using cyanobacterial species / V. Shashirekha in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 11 (11/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 11 (11/2005) . - p. 419-426 Titre : Bioremediation of tannery effluents and chromium containing wastes using cyanobacterial species Type de document : texte imprimé Auteurs : V. Shashirekha, Auteur ; Mahadeswara Swany, Auteur ; M. Pandi, Auteur Année de publication : 2005 Article en page(s) : p. 419-426 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Heavy metal pollution of ground and surface waters by industrial effluents has become a serious threat to the environment especially in developing countries. One example of heavy metal pollution is the high chromium containing liquid effluents discharged from tanneries. Though many conventional physico-chemical methods are currently being practiced, biotechnological methods are becoming attractive alternatives, as they are economical and eco-friendly. In this context, the search for innovative and eco-friendly biotechnologies to remove toxicants from effluents has focused attention on the detoxification capacity of a variety of microbes especially cyanobacteria. In the present work, preliminary studies were carried out using two species of cyanobacteria for the treatment of tannery effluents with special reference to trivalent chromium. The effects of different concentrations of chromium on the growth response of these species in terms of biomass and chlorophyll-a were studied in addition to their capacity to accumulate chromium. These species were very effective in removal of trivalent chromium (95 - 100%) besides reducing BOD and COD of the effluent. SDS-PAGE and FTIR studies indicated the formation of a complex with protein. Better performance of the species in the field conditions gives positive indication of their usefulness in treatment of tannery effluent. En ligne : https://drive.google.com/file/d/1lgUZNM0K6BUwAl-msQNb-3Q-dQ9g9Inm/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4050 [article]

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Oxidative dehairing by sodium percabonate / William N. Marmer in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 11 (11/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 11 (11/2005) . - p. 427-431 Titre : Oxidative dehairing by sodium percabonate Type de document : texte imprimé Auteurs : William N. Marmer, Auteur ; Robert L. Dudley, Auteur Année de publication : 2005 Article en page(s) : p. 427-431 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The dehairing of cattle hides generates large quantities of waste that are of environmental concern as they have a large biological and chemical oxygen demand. We had demonstrated that the traditional dehairing agent, sodium sulfide, can be replaced by an oxidative dehairing agent, sodium perborate, thereby reducing the amount of hazardous chemical in the waste stream. The by-product of perborate is borate, however, which is suspected to accelerate the degradation of wooden dehairing drums. In this paper we report the results of a study that uses sodium percarbonate as the dehairing agent. Although oxidatively dehaired hides exhibit a slight resistance to acid dye uptake, leather produced from percarbonate-dehaired hides in all other studied aspects -- shrinkage temperature, chromium uptake, elongation at break, toughness index -- compared favorably to leather from sulfide-dehaired hides. En ligne : https://drive.google.com/file/d/1glaNJAqIP6k3QpRMjNZpC2rdWmGVtcWZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4051 [article]

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Mechanism of vegetable tannin-aldehyde combination tannage / Zhongbing Lu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 11 (11/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 11 (11/2005) . - p. 432-437 Titre : Mechanism of vegetable tannin-aldehyde combination tannage Type de document : texte imprimé Auteurs : Zhongbing Lu, Auteur ; Bi Shi, Auteur ; Yi Tao, Auteur ; Wenhua Zhang, Auteur ; Xuepin Liao, Auteur Année de publication : 2005 Article en page(s) : p. 432-437 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Using (+)-Catechin and (+)-gallocatechin as models for condensed vegetable tannins, the reaction mechanism between the flavonoid ring structure and aldehyde was elucidated based on the density functional theory (DFT) calculation. The results show that A-ring of the flavonoid structure is the nucleophilic center, according to the atomic charges and the distribution of highest occupied molecular orbital (HOMO), which implies that A-ring is more reactive to aldehydes. As to (+)-catechin, C-6 and C-8 positions are of equal reactivity to aldehydes, according to the energy transformations in the reaction. C-8 of (+)-gallocatechin is more reactive than C-6 in the same molecule. The difference of B-rings between (+)-catechin and (+)-gallocatechin influences the distribution of HOMO in molecules and consequently leads to difference of relative reactivity between C-6 and C-8-positions in flavonoid structures, in agreement with the NMR observations. The difference of HOMO distributions of (+)-catechin and (+)-gallocatechin imply that gallocatechin-based tannins, such as mimosa tannins, have higher reactivity to aldehyde, and are more suitable for tannin-aldehyde combination tannage. En ligne : https://drive.google.com/file/d/1cHECt3xPcyyVPCDBd_-Ovu9K6dDC2bPD/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4052 [article]

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Nondestructive testing using rotational acoustic emission sensors / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 11 (11/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 11 (11/2005) . - p. 438-446 Titre : Nondestructive testing using rotational acoustic emission sensors Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Gary L. DiMaio, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2005 Article en page(s) : p. 438-446 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : At the present time, testing the mechanical properties of leather is a destructive process, wherein cutouts are taken off the tannery floor for mechanical testing. Under a cooperative R&D agreement (CRADA), we recently investigated the feasibility of using the acoustic emission (AE) technique to dynamically and nondestructively measure the mechanical properties of leather. The long-range goal of this collaborative effort is the production of an AE instrument, which will provide the leather industry with a nondestructive way in which to monitor the quality of leather at each of the leather-making stages. In this investigation, a rotational acoustic sensor was rolled across the leather samples to collect their AE quantities such as waveforms, frequency, hits, counts and energy. The software AE-Win was utilized to capture and record the data, and the neural network software NOESIS was subsequently used for data analysis. Observations showed an excellent correlation between the softness of leather and the corresponding cumulative acoustic counts. We also used this dynamic method to characterize the grain break of leather. Results showed that the difference in grain break could be determined from the amount of acoustic energy collected from moving the AE sensor over a leather sample laid inside a half pipe. The grain break decreased as the AE energy increased. The higher AE energy is an indication of stiffer leather; therefore, the results revealed that stiffer leather is prone to bad grain break. Data also demonstrated that the thicker samples tended to have poorer grain break. We derived a predictive model that could be very useful for nondestructively testing grain break using the AE method described in this report. Results also showed a close relationship between the tensile strength and AE energy or duration obtained from testing. In short, this study demonstrated that the softness, tensile strength and grain break could be nondestructively determined by measuring the acoustic quantities with a rotational sensor rolling over the leather. En ligne : https://drive.google.com/file/d/15RHf9eqh8X2vejs8JmB1U64JD3Z-Jemg/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4053 [article]

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