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Preparation and optimisation of a novel modified bioflocculant for removal of nitrogen in tannery wastewater in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 1 (01-02/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 1 (01-02/2022) . - p. 1-6 Titre : Preparation and optimisation of a novel modified bioflocculant for removal of nitrogen in tannery wastewater Type de document : texte imprimé Année de publication : 2022 Article en page(s) : p. 1-6 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biofloculant Cuirs et peaux -- Industrie -- Aspect de l'environnement Eau -- Épuration -- Élimination des composés organiques Eaux usées -- Epuration Eaux usées -- Teneur en azote total Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this work, a modified bioflocculant was successfully prepared involving HM-636 amphoteric starch measuring the effect of the removal of total nitrogen from tannery wastewater as its optimisation index. Specifically, the effects of the modified bioflocculant on the removal of total nitrogen from tannery wastewater were investigated by the single-factor optimisation experiment and orthogonal optimization experiment, and the conclusions obtained were that the optimum factors were: amphoteric starch 0.2g/L, bioflocculant 3.5g/L, initiator (0.02mol/L) 2.5mL, reaction time of the second stage 28 minutes, rotation speed of mixing 270r/min, reaction temperature 35°C, and reaction system pH5.0. The total nitrogen removal rate of 79.81% could be obtained under these optimal reaction conditions. In other words, the modified bioflocculant has an improved effect on the removal of total nitrogen. Note de contenu : - EXPERIMENTAL PROCEDURE : Materials - Preparation of seed solution - Preparation of bioflocculant - Preparation of modified bioflocculant - Preparation of simulated tannery wastewater - The removal of total nitrogen from tannery wastewater - RESULTS AND DISCUSSION : Single-factor optimisation - The orthogonal optimisation - Table 1 : Factor level table for preparation of HM-636 modified bioflocculant - Table 2 : Experimental design and range analysis of modified bioflocculant - Table 3 : Variance anlaysis of HM-636 modified bioflocculant En ligne : https://drive.google.com/file/d/1niVbC7EEr59iygXSHwBiXztIud9j7LDr/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36967 [article]

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In-depth understanding of the leather fatliquoring process : A review / M. A. Habib in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 1 (01-02/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 1 (01-02/2022) . - p. 13-19 Titre : In-depth understanding of the leather fatliquoring process : A review Type de document : texte imprimé Auteurs : M. A. Habib, Auteur Année de publication : 2022 Article en page(s) : p. 13-19 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Collagène -- Structure Emulsification Emulsions Huiles et graisses Produits de nourriture du cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanning involves economic and environmental benefits, it transfers low-value by-products (animal hide and skin) into value-added products (natural leather). Introducing fatty matter into the inter-spaces of tanned leather (stiff and unusable) — fatliquoring, restores the fat removed in tanning and restores flexibility to the leather. This article provides an in-depth understanding of the process. Previous chemical treatment and building of a fatliquor emulsion are the watershed points in the process and the main factor affecting the efficiency of the process is the arriva) of the fatty substance to the collagen fibrils which are thus coated with a thin layer of fats that promote sliding of fibrils and prevent adhesion. Successful fatliquoring is achieved through using an emulsion of specific particle size to enable the oil droplets to penetrate the leather reaching to fibril level. Note de contenu : - Collagen protein structure - Fibril bundles and fatliquor mechanism - Emulsifying of fatty matter and emulsion efficiency - Types of fatliquor emulsion - Modified natural oil and fat used in fatliquoring En ligne : https://drive.google.com/file/d/1D3rKpsxbZyVW-TQFEarRV5giierkoamK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36968 [article]

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Evaluation of a mixture of castor oil and polyvinylpyrrolidone for the lubrication of dry / Gomaa Abdel-Maksoud in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 1 (01-02/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 1 (01-02/2022) . - p. 20-31 Titre : Evaluation of a mixture of castor oil and polyvinylpyrrolidone for the lubrication of dry Type de document : texte imprimé Auteurs : Gomaa Abdel-Maksoud, Auteur ; Nareman Mahmoud Hussien, Auteur ; Nadeen Al-Arif, Auteur ; Asmaa Gouda, Auteur ; Wael S. Mohamed, Auteur ; Medhat Ibrahim, Auteur Année de publication : 2022 Article en page(s) : p. 20-31 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chimie analytique Cuirs et peaux -- Propriétés mécaniques Evaluation Huile de ricin et constituants Mélanges (chimie) Polyvinylpyrrolidone Produits de nourriture du cuir Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Leather artifacts are to be found in varied archaeological and historical places (museums, storages, libraries, excavation areas). Improper environmental conditions (such as relative humidity, temperature, excess light, pollution etc.) and poor handling can affect such artifacts and lead to their increased hardness and dryness. This study aims to evaluate castor oil and polyvinylpyrrolidone (PVP) as individual materials and as a mixture at different concentrations for the lubrication of vegetable-tanned leathers. Accelerated heat ageing at different temperatures was used. The analytical techniques used for the evaluation process were digital light microscopy, scanning electron microscope (SEM), change of colour, attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR), and mechanical properties (tensile strength and elongation). Investigation of the surface morphology by microscopy proved that a low concentration of castor oil in the mixture gave good fibre distribution and the grain surface pattern was established for the treated and aged treated samples. The colour value and total colour difference of the treated and aged treated samples with a low concentration of castor oil were better than at a high concentration. ATR-FTIR proved that the castor oil and PVP mixture protects leather from deterioration as no free radicals were observed in the spectra. Mechanical property values proved that the use of the lubricant protected leather from accelerated heat ageing. It is recommended that, a mixture of castor oil and PVP with a ratio of 10:90 could be applied for the lubrication of dry vegetable-tanned leather artifacts. Note de contenu : - MATERIALS AND METHODS : Materials - Methods - RESULTS AND DISCUSSION : Digital light microscope investigation - Investigation of the surface morphology by SEM - Measurement of colour change - ATR-FTIR analysis of the treated leather with the mixture of castor oil and PVP - Measurement of mechanical properties (tensile strength and elongation) - Table 1 : Change of colour of vegetable-tanned leather samples treated with the mixture of castor oit and polyvinyl pyrrolidone before and after accelerated heat ageing - Table 2 : Tensile strength and elongation of vegetable-tanned leather samples treated with the mixture of castor oil and polyvinylpyrrolidone at different concentrations before and after accelerated heat ageing En ligne : https://drive.google.com/file/d/1e9xcGT62rjdFLdc7QkeAc98_0_EYUg-W/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36969 [article]

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Tannases and other fungal enzymes applicable to the transformation of tannins and their potential for bioremediation of effluents from the leather industry / Lorena V. Cortizo in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 1 (01-02/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 1 (01-02/2022) . - p. 32-41 Titre : Tannases and other fungal enzymes applicable to the transformation of tannins and their potential for bioremediation of effluents from the leather industry Type de document : texte imprimé Auteurs : Lorena V. Cortizo, Auteur ; Laura M. I. Lopez, Auteur ; N. Saparrat, Auteur Année de publication : 2022 Article en page(s) : p. 32-41 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bioremédiation Déchets industriels -- Elimination Eaux usées -- Epuration Enzymes fongiques Tanins Tannases Les tannases constituent une classe d'enzymes, de référence EC EC 3.1.1.20), qui catalysent les réactions chimiques : digallate + H2O ⇌ {\displaystyle \rightleftharpoons } \rightleftharpoons 2 gallate Les deux substrats de cette enzyme sont donc l'digallate et l'H2O, et son produit de réaction est le gallate. Cette enzyme appartient à la famille des hydrolases et plus spécifiquement à ceux qui agissent sur les liaisons ester carboxyliques. Le nom de cet classe d'enzyme est acylhydrolase tannique. Parmi les autres noms en vigueur, on trouve tannase S et acetylhydrolase tannique. En plus de catalyser l'hydrolyse de la liaison ester centrale entre les deux anneaux aromatiques du digallate (activité de dépsidase), les tannases peuvent aussi avoir une activité d'estérase (hydrolyse de la fonction ester terminale attachée à une des deux anneaux aromatiques). Les tannases sont des enzymes clé dans la dégradation des gallotanins, un type de tanins hydrolysables. On les trouve dans divers groupes de microorganisme, incluant les bactéries de la panse. Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The use of fungal enzymes, such as tannases and oxidative enzymes, in the tannin bioconversion process offers great advantages over other biological and chemical technologies in terms of safety, re-use, and better control of process parameters, and is also a profitable and environmentally friendly method. Some reports have shown that different fungi can remove tannins from effluents, transforming them and/or detoxifying them, and using them, in some cases, as their only source of carbon. By means of different enzymes, these fungi trigger reactions that lead to the elimination of water-soluble tannins, which are the cause of toxicity in surface water bodies. Thus, these microorganisms are attractive to obtain enzyme cocktails applicable to the bioremediation of effluents rich in tannins, such as those derived from the leather industry. This review aims to provide updated information on fungal sources of enzymes able to transform tannins, with emphasis on tannases, and to show alternatives to culture tannase-producing fungi and obtain the enzymes and their activity in immobilization matrices. The inducible nature of the fungal synthesis of tannases reveals the importance of acquiring basic knowledge about the physiology of tannase-producing fungi and the need for studies in different culture and scaling systems. Note de contenu : - Tannins as targets of fungal enzymes - Potential of fungal enzymes to remove tannins : Tannases - Oxidative enzymes - Fungal tannase production methodologies : Solid-state fermentation (SSF) - Submerged fermentation (SMF) - Fungi and their activity in the removal and/or detoxification of tannins present ineffluents from the leather industry - Fig. 1 : Main mechanical structures of tannins - Fig. 2 : Possible mechanisms involved in tannin removal by fungi - Table 1 : Production of tannases from fungal culture systems under solid state-fermentation conditions (SSF) by using natural substrates - Table 2 : Fungal culture systems under submerged fermentation (SMF) for tannase production En ligne : https://drive.google.com/file/d/1n9kFXj5bJpWHkYr0JY6KpK4cgxxUU52m/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36970 [article]

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