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Mention de date : 11-12/2000
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Determination of trace chromium (VI) ion chrome tanning agents by flow injection / Zhang Xinshen in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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[article]
Titre : Determination of trace chromium (VI) ion chrome tanning agents by flow injection Type de document : texte imprimé Auteurs : Zhang Xinshen, Auteur ; Xiaoping Jiang, Auteur ; Minghua Liu, Auteur ; Yun Den, Auteur Année de publication : 2000 Article en page(s) : p. 255-257 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adsorption
Agents de tannage -- Analyse
Analyse par injection en flux continuL’analyse par injection en flux continu (Flow Injection Analysis FIA) consiste, dans son principe le plus simple, en l’injection d’un petit volume (µL) d’une solution échantillon dans un fluide en mouvement ; ce liquide transporteur, qui se déplace de façon continue, n’est pas segmenté, et la zone formée par l’injection répétée de l’échantillon est ainsi transportée vers un détecteur afin d’enregistrer les variations d’un paramètre physique ou physico-chimique caractéristique de l’échantillon ou, le plus souvent, de l’un de ses éléments constitutifs.
Chélates
Chrome hexavalent
Chrome trivalent
Ions chrome
Oxyde de magnésiumL'oxyde de magnésium, communément appelé magnésie, a pour formule MgO et se présente sous la forme de poudre blanche très fortement basique absorbant l'eau et le dioxyde de carbone présents dans l'atmosphère.
STRUCTURE : L'oxyde de magnésium est un cristal ionique. L'oxyde de magnésium a une structure comparable à celle du chlorure de sodium7. Cela se traduit par
Un réseau d'anion oxygène formant une structure de type cubique à faces centrées
Un réseau de cation magnésium occupant l'ensemble des sites octaèdriques.
L'oxyde de magnésium est un matériau modèle des cristaux ioniques car la faible électronégativité du magnésium, et la forte électronégativité de l’oxygène font que la structure de l’oxyde de magnésium peut s’expliquer quasi uniquement grâce à des interactions entre des particules ponctuelles chargées 10.
La surface de l'oxyde de magnésium la plus stable dans le vide est obtenue en réalisant une coupe selon le plan cristallographique (100). Les particules d'oxyde de magnésium produites par combustion du magnésium métallique présentent d'ailleurs une forme cubique révélatrice de la présence de ces plans. Néanmoins, en présence d'eau, la surface de l'oxyde de magnésium est couverte d'ions hydroxyles qui stabilisent les plans (111)
PRODUCTION : La majeure partie de l'oxyde de magnésium est actuellement obtenue soit à partir de carbonate de magnésium MgCO3 qui constitue certains minéraux tels que la magnésite, soit à partir de chlorure de magnésium que l'on extrait de l'eau de mer ou de saumures souterraines.
Précipitation (chimie)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A large amount of Cr3+ ion can significantly interfere with the determination of trace amounts of Chromium (VI) ion in chrome tanning agents. Therefore, two new preparation methods of precipitation and adsorption are put forward here to eliminate the interference of Cr3+ ion.
According to the experiments, magnesium oxide (MgO) was chosen as the best precipitating agent for Cr3+ ion, the adsorption efficiency of the chelating resin was better than any other resin.
The content of chromium (VI) ion was determined by flow injection analysis (FIA). In order to assess the feasibility of two preparation methods, tests of precision and recovery were conducted. The results show that the variation coefficient is less than 1.6 percent with the recoveries ranging from 95.0 % to 102 %. Therefore, the precipitation and adsorption are feasible for the preparation of Cr (VI) samples in chrome tanning agents. Moreover, they have such advantages as simple and convenient preparation.Note de contenu : - EXPERIMENTAL : Chemical reagents - Instrumentation - Preparation of stock solutions - Pretreatment of the samples - Precipitation treatment - Adsorption treatment - Preparation of the reaction solution - Analytical procedure
- RESULTS AND DISCUSSION : Tests of linearity and precision - Choice ofprecipitating agent - Choice offactors affecting the precipitation treatment - Choice of the adsorption resins - Choice of factors affecting the adsorption treatment - Detection limit - Recovery tests
- ANALYSIS OF THE SAMPLESEn ligne : https://drive.google.com/file/d/1Rxu4MjoIN0mg-byfKDmx2YmGGGSRKiz2/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40814
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000) . - p. 255-257[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Oxidising degradation of Valonia extract and utilisation of the products. Part 1. Oxidising degradation of Valonia extract and characterisation of the products / Bi Shi in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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Titre : Oxidising degradation of Valonia extract and utilisation of the products. Part 1. Oxidising degradation of Valonia extract and characterisation of the products Type de document : texte imprimé Auteurs : Bi Shi, Auteur ; Ying Di, Auteur ; Youjie He, Auteur ; Lijiang Song, Auteur ; Yu Zhao, Auteur Année de publication : 2000 Article en page(s) : p. 258-262 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aluminium trivalent
Chrome trivalent
Complexation (chimie)
Couleur
Extraits de plantes
Oxydation
Peroxyde d'hydrogèneLe peroxyde d'hydrogène (H2O2), communément appelé eau oxygénée ou encore perhydrol (appellation industrielle), est un composé chimique liquide et visqueux, aux puissantes propriétés oxydantes (il est aussi réducteur). C'est donc un agent blanchissant efficace qui sert de désinfectant et (à haute concentration) d'oxydant ou monergol dans les fusées spatiales.
Poids moléculaires
Résistance chimique
Tanins végétaux
Valonia et constituantsValonia est un genre d'algues vertes de la famille des Valoniaceae. La taille d'une seule cellule pluri-nucléée peut atteindre 2 cm chez certaines espèces. (Wikipedia)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Oxidation using H2O2 brings about degradation of valonia extract. Three typical products with novel properties were obtained when 20%, 40% and 60% H2O2 (conc. 50%) were used. Determinations indicated that the oxidising reaction leads to lowering of molecular weight, lightening of colour, improving of acid and salting-out resistances and increasing of hydrophilic groups, carboxyl in particular. The more interesting results are that penetrating rates of the degraded products in pelt are markedly accelerated and that the alkali resistance of complex compounds of the products and Cr(III) or Al(III) is considerably increased. The effects above are enhanced with increasing offer of H20.The conditions for oxidising degradation are described and the potentials of utilising the products are discussed. Note de contenu : - EXPERIMENTAL PROCEDURES : Oxidising degradation of valonia extract - Determination of molecular weight distribution - Colour determination - Characterisation of structure - Acid resistance and salting-out effect determinations - Determination of tanning property - Complexing characteristics with Al(III) and Cr (III)
- RESULTS AND DISCUSSION
- Table 1 : Molecular weight distributions of oxidised degradation products of valonia extracts
- Table 2 : The colour of valonia extract and its oxidised degradation products
- Table 3 : Precipitate ratios (%) of valonia extract and its oxidised degradation products at different pH*
- Table 4 : Precipitate ratios (%) of valonia extract and its oxidised degradation products in NaC1 solution
- Table 5 : The tanning properties of valonia extract and its oxidised degradation products*
- Table 6 : Precipitating pH of complex solutions of oxidised degradation products and Cr(III)
- Table 7 : Precipitating pH of complex solutions of oxidised degradation products and Al(III)En ligne : https://drive.google.com/file/d/1MNgqR-q-yGLMFjML87uHVZ7aRinbwt3x/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40815
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000) . - p. 258-262[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Thermal properties of leather and their relation to structural mechanical and handle characteristics in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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Titre : Thermal properties of leather and their relation to structural mechanical and handle characteristics Type de document : texte imprimé Année de publication : 2000 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux -- Propriétés thermiques
ToucherIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Research has been carried out to investigate the relationship of both static and dynamic thermal properties of leather with structural (thickness, apparent density), mechanical (creep index, bagginess index, compression) and handle characteristics (softness, stiffness). Eighteen leathers of different origin, application and characteristics were evaluated. Note de contenu :
- Table 1 : Origin, application and characteristics of the 18 leathers studied
- Table 2 : Values of thickness, apparent density, compression and bagginess index
- Table 3 : Values of softness, creep Index and the subjective assessment of softness and stiffness
- Table 4 : Variable weights of "component 1" and "component 2"
- Table 5 : Values of thermal resistance and thermal penetration coefficient
- Table 6 : Analysis of Correlation between the thermal properties and
"component 1", "component 2"En ligne : Analysis of Correlation between the thermal properties and “Coinpoiient I”, [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40816
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000)[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Removal by an adsorbent resin of non-ionic surfactants used in tannery processes / A. Rozzi in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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Titre : Removal by an adsorbent resin of non-ionic surfactants used in tannery processes Type de document : texte imprimé Auteurs : A. Rozzi, Auteur ; M. Antonelli, Auteur ; C. Angeretti, Auteur ; R. Mantovani, Auteur ; E. Scaglia, Auteur Année de publication : 2000 Article en page(s) : p. 266-270 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorbants et adsorbants
Déchets industriels -- Elimination
Eaux usées -- Décontamination
Eaux usées -- Teneur en surfactants
SurfactantsIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A new process to remove non-ionic surfactants from tannery wastewater, using a bed of adsorbent synthetic resin, has been investigated at laboratory and pilot scale.
A small pilot column (V=2 litres) has been tested at a tannery in Northern Italy. The wastewater was filtered on a sand-bed and then fed to the adsorbent resin. The column operated at very short nominal residence time, lower than 7 minutes.
Non-ionic surfactants were monitored in the column influent and effluent. Two regeneration procedures were tested : hot water with soda nd solvent extraction by acetone. Only the latter was quite successful and allowed a complete recovery of the absorbate. More basic experiments were carried out at laboratory scale using synthetic solutions made of tap water and a non-ionic surfactant industrial product to evaluate equilibrium isotherms and adsorption kinetics. A first approximation economical evaluation of the process was also carried out.
The experimental results indicate that the removal of non-ionic surfactants from industrial wastewater (tannery effluent) by adsorbent resin is feasible and economically competitive.Note de contenu : - MATERIALS AND METHODS : Wastewater - Synthetic solution - Adsorbent resin - Adsorption column - Kinetic tests and equilibrium iso therms
- RESULTS AND DISCUSSION : Adsorption tests on pilot column
- Batch regeneration with soda
- Batch regeneration with acetone
- Kinetic tests and equilibrium isotherms
- Cost evaluation
- Table 1 : Main characteristics of the tannery WWTP effluent
- Table 2 : Main characteristics of the RMO2O resin
- Table 3 : Main operating parameters of adsorbent column during the two cycles
- Table 4 : Characteristics of the eluate and wash water for NaOH regneration
- Table 5 : Main results of acetone regeneration procedure on two samples of resin
- Table 6 : Values of kinetic constants K for the two resin granulometry fractions and for 30mg/l Sandozine initial concentration and correlation coefficient R2En ligne : https://drive.google.com/file/d/1zo480kXIyIH5FbluBImWv715v-jI2_mw/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40817
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000) . - p. 266-270[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Using ashes from incineration of chromium sulphate tanned leather scrap - Part 1 : Characterization of ashes and chromium extraction in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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Titre : Using ashes from incineration of chromium sulphate tanned leather scrap - Part 1 : Characterization of ashes and chromium extraction Type de document : texte imprimé Année de publication : 2000 Article en page(s) : p. 271-275 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation
Cendres -- Teneur en chrome
Chrome hexavalent
Cuirs et peaux -- Déchets -- Recyclage
Extraction (chimie)
Incinération
Récupération (Déchets, etc.)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chromium is the basis of leather manufacture and its extractable reserves are limited in distribution, mainly in South Africa, Zimbabwe and ex-USSR countries. Almost 20% of the metal is used by the chemical industry where one third of it goes into leather production as chromium sulphate tanning agent.
The European Union depends on chromium imports.
After burning leather scrap—tanned with chromium sulphate-the resulting very rich chromium ashes may present chromium (VI) in such a concentration that it becomes a hazardous waste and needs careful handling.
Thus, both economic and environmental reasons suggest the use of these ashes. This paper mainly summarizes some of the conclusions of the research carried out during the execution of CRAFT project BRST-CT96-5085, where leather incineration ashes generated by two different pilot combustion systems, respectively a fixed grill incinerator (FGI) and a fluidized bed incinerator (FBI) were characterized and chromium was leached using a mixed pyrometallurgical and hydrometallurgical route as well as a full hydrometallurgical route.Note de contenu : - EXPERIMENTAL PROCEDURES : Methods and procedure
- RESULTS AND DISCUSSION : Characteristics of ashes - Chromium extraction from ashes by a hydrometallurgical route - Chromium extraction from ashes by a pyrometallurgical and hydrometallurgical route - Silica leaching from the ashes
- Table 1 : XRF results of the FGI and FBI ash analyses
- Table 2 : Influence of acid concentration, grinding, temperature and time on chromium recovered from FGI ashesEn ligne : https://drive.google.com/file/d/1CbRiDpse_L8eNNFYuP0Qvf6_lsRNlsmM/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40818
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000) . - p. 271-275[article]Exemplaires
Code-barres Cote Support Localisation Section Disponibilité aucun exemplaire Development of a leather processing method in narrow pH profile : Part 1. Standardisation of dehairing process / Palanisamy Thanikaivelan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 84, N° 6 (11-12/2000)
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Titre : Development of a leather processing method in narrow pH profile : Part 1. Standardisation of dehairing process Type de document : texte imprimé Auteurs : Palanisamy Thanikaivelan, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur Année de publication : 2000 Article en page(s) : p. 276-284 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux
Epilage enzymatique
Essais dynamiquesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : An attempt has been made to develop a method for processing leathers in a narrow range of pH viz., 4.0 8.0. A process for dehairing at a pH of around 8.0 has been explored. This has been achieved by employing a commerical enzyme in combination with small quantifies of sodium sulphide. A method for applying the dehairing formulation on the grain side was established. Hair removal was shown to be complete using scanning electron microscopy (SEM ) and cystine content analysis. Potential grain damage by the enzyme formulation was avoided through process control measures and the effectiveness of such methods was established by investigation by scanning electron micrographs. Strength and bulk properties of the experimental leathers appear to show some improvement as compared to the leathers made using conventional processes. The process enjoys an environmental benefit by significantly reducing the COD load in the effluent. Improved chrome content in the grain surface of the butt region adds an additional benefit to the dehairing process developed. Note de contenu : - EXPERIMENTAL PROCEDURE : Standardisation of dehairing process - Comparison of effectiveness of the developed process with a conventional unhairing process
- RESULTS AND DISCUSSION : Standardisation of dehairing system - Developed dehairing process vs conventional dehairing process
- Table 1 : Composition of paste for determination of depilatory mixture
- Table 2 : Composition of paste for different methods of application
- Table 3 : Composition of paste for optimisation of depilatory mixture
- Table 4 : Physical testing of control and experimental leathers
- Table 5 : Stratigraphic distribution of chromium
- Table 6 : Composite liquor analysisEn ligne : https://drive.google.com/file/d/1UYGono16nGaXlpW4eI3EptAUIpd2gY6A/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40819
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 84, N° 6 (11-12/2000) . - p. 276-284[article]Exemplaires
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