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Transformation of sulphur in advanced integrated wastewater pond system treating tannery effluent / I. Tadesse in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 6 (06/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 6 (06/2003) . - p. 203-215 Titre : Transformation of sulphur in advanced integrated wastewater pond system treating tannery effluent Type de document : texte imprimé Auteurs : I. Tadesse, Auteur ; F. B. Green, Auteur ; J. A. Puhakka, Auteur ; S. A. Isoaho, Auteur Année de publication : 2003 Article en page(s) : p. 203-215 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : An outdoor experiment was conducted to study the fate and transformation of sulphur in tannery wastewater being treated by a novel pond-based wastewater treatment technology known as the Advanced Integrated Wastewater Pond System® or AIWPS®. The experiment used a research-scale AIWPS® consisting of a primary Advanced Facultative Pond (AFP) with submerged Fermentation Pit (FP), Secondary Facultative Pond (SFP) and Maturation Pond (MP) all arranged in series. Screening and settling were included as sequential pretreatments. The sulphate and sulphide concentrations of the raw tannery wastewater varied between 150 and 3,500 mg/l and 100 and 800 mg/l, respectively. In a three-phased experiment, the AIWPS® facility was subjected to increasing organic and sulphate loadings. With sulphate loading rates of 78-244 g/m3-d over the experiment phases, the AFP with the FP attained a total sulphur (SO4=-S + S=-S) removal of 67-79%. Dissimilar sulphate reduction in the submerged FP followed by photosynthetic sulphide oxidation into elemental sulphur in the solar illuminated upper water layers was the major sulphur removal mechanism in the AFP. The overall organics removal performance of the AFP was not adversely affected by increased organics and sulphate loading rates. With an increase of sulphate loading from 78 g/m3-d during phase 1 to 122 g/m3-d during phase 2 and a corresponding COD loading increase from 560 to 1480 g/m3-d, COD removal efficiency in the AFP dropped by only 4%. Some process instability with inhibition of methane fermentation in the AFP and domination of microalgae by photosynthetic sulphur bacteria in the SFP were observed during phase 3 when the AFP was subjected to extreme sulphate and COD loading rates of 244 and 1,860 g/m3-d, respectively. The extreme loading rates decreased the COD removal efficiency of the AFP by only 25%. Odour free operations and high organics and sulphur removal performances of the AFP were due to the proliferations of microbial morphotypes similar to genera: Thiocystis, Rhodobacter, Rhodopseudomonas and Rhodospirillum. A sulphur scum with purity of up to 35% sulphur was recovered from the AFP water surface. Gentle mixing in the upper water layers of the SFP remedied the unwanted domination of algae by pink sulphur bacteria. En ligne : https://drive.google.com/file/d/1bcPItbM77wUkVCS2nSykHJKjzyrCEyrC/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4138 [article]

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Rapid oxidative unhairing with alkaline calcium peroxide / Andrew G. Gehring in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 6 (06/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 6 (06/2003) . - p. 216-223 Titre : Rapid oxidative unhairing with alkaline calcium peroxide Type de document : texte imprimé Auteurs : Andrew G. Gehring, Auteur ; David G. Bailey, Auteur ; Gary L. DiMaio, Auteur ; Robert L. Dudley, Auteur ; William N. Marmer, Auteur ; Chad E. Mazenko, Auteur Année de publication : 2003 Article en page(s) : p. 216-223 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Sodium sulfide is frequently used to remove hair from animal hides during tanning operations. However, since sodium sulfide is an environmental pollutant that is quickly converted to highly toxic hydrogen sulfide gas if accidentally exposed to acid, an alternative unhairing agent is desired. We have observed that calcium peroxide may be used to rapidly unhair cattle hides with efficiency similar to that of sodium sulfide. Under alkaline conditions (pH ~13), 5-15 % (w/w) calcium peroxide mixture applied in two back-to-back applications, afforded either complete or nearly complete unhairing within 10 minutes of total reaction time at a reaction temperature of ~45°C. Most of the removed hair was essentially broken down or dissolved in this rapid oxidative hairburn process. Alternatively, intact, long strands of hair could be removed and recovered (hairsave) with a single application of the calcium peroxide solution (solids removed) followed by rapid adjustment of the hair solids to an approximately neutral pH. However, hair stubble remained on the hide after subjected to this latter hairsave process. The alkaline calcium peroxide hairburn and hairsave processes were studied using hide pieces (laboratory-scale experiments) and matched sides (pilot-scale experiments) and compared to conventional hairburn with sodium sulfide. The studies revealed that shrinkage temperature, physical testing, dye shading, dye levelness and grain appearance were comparable. In addition, several commercially available non-sulfide sharpening agents, added during reliming of hide pieces, were demonstrated to remove residual hair stubble that remained after rapid oxidative hairburn. En ligne : https://drive.google.com/file/d/1IHk1VAMX6HZM61vQsuat_uami76ko9cI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4139 [article]

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Physicochemical properties of collagen isolated from calf limed splits / Guoxing Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 6 (06/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 6 (06/2003) . - p. 224-229 Titre : Physicochemical properties of collagen isolated from calf limed splits Type de document : texte imprimé Auteurs : Guoxing Li, Auteur ; Fumio Nakamura, Auteur ; Kazuaki Takenouchi, Auteur ; Shigeharu Fukunaga, Auteur Année de publication : 2003 Article en page(s) : p. 224-229 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Samples of collagen extracted from calf limed splits by three different methods (acetic acid, pepsin, and alkali treatments) were characterized with respect to their thermal stability, subunit composition, and morphology of fibril network. Differential scanning calorimetry showed that the denaturation temperature of pepsin-treated collagen was very similar to that of commercial type I collagen but much higher than those of acetic acid-treated collagen and alkali-treated collagen. Analysis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting revealed that the subunit composition in collagen solution samples appeared to be major type I collagen and minor type III collagen. Scanning electron microscopy showed that acetic acid-treated collagen had a porous fibrillar network structure, while pepsin-treated collagen and alkali-treated collagen had membranous networks resembling that of commercial type I collagen. En ligne : https://drive.google.com/file/d/1YPgwRFcvcyJxXyujPauXtD8w83jXMoyz/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4140 [article]

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Diffusion rate enhancement in leather dyeing with power ultrasound / Venkatasubramanian Sivakumar in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 6 (06/2003)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 6 (06/2003) . - p. 230-273 Titre : Diffusion rate enhancement in leather dyeing with power ultrasound Type de document : texte imprimé Auteurs : Venkatasubramanian Sivakumar, Auteur ; P. G. Rao, Auteur Année de publication : 2003 Article en page(s) : p. 230-273 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Use of power ultrasound as a non-polluting method for accelerating/performing chemical as well as physical processes is gaining importance. The effect of power ultrasound in the dyeing of full chrome cow crust leather is compared with dyeing in the absence of ultrasound as a control experiment both in a stationary as well as conventional drumming condition. Ultrasonic probe (20 kHz, 0-400 W) was used for the experiments. Experiments were carried out with Acid red dye. The effect of ultrasonic output power has been studied and optimized. The influence of non-ionic surfactant or air bubbles in dye bath for ultrasonic assisted dyeing has been studied and found to be beneficial. The effect of ultrasonic pulse mode to get more benefits has also been studied. The diffusion coefficient has been calculated for dyeing with and without ultrasound and about 14 times improvement has been obtained from 80 W of ultrasound. En ligne : https://drive.google.com/file/d/1vCyssZwF-5FgptfXlTrM9Vr_VgLkmOwF/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4141 [article]

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