An effective and harmless recycling technology for hazardous chrome-tanned leather wastes / Minghui Li in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 108, N° 2 (03-04/2024)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 108, N° 2 (03-04/2024) . - p. 67-77 Titre : An effective and harmless recycling technology for hazardous chrome-tanned leather wastes Type de document : texte imprimé Auteurs : Minghui Li, Auteur ; Xu Zhang, Auteur ; Honghong Chen, Auteur ; Sadaqat Ali Chattha, Auteur ; Xin Yan, Auteur ; Biyu Peng, Auteur Année de publication : 2024 Article en page(s) : p. 67-77 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents de tannage Chimie analytique Chrome -- Recyclage Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Déchets -- Recyclage Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés physiques Déchromage Hydrolysat de collagène Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Utilizing leather production waste to create raw materials for leather chemicals, and reintroducing it into the leather making processing, represents an ideal approach to achieving an “internal circular economy” within the leather industry. This study focuses on the reutilization of dechromed collagen fibres, obtained from chromium shavings, to generate a retanning filling. The effects of hydrolysis conditions on the viscosity, and gel strength of the dechromed collagen hydrolysates were investigated. The application effectiveness of the collagen hydrolysates with different particle sizes in the leather retanning filling process was also compared. The findings indicate that alkali hydrolysis is more conducive to producing collagen hydrolysates with a relatively higher proportion of medium and low molecular weight components, while acid hydrolysis favours the production of collagen hydrolysates rich in high molecular weight components. Additionally, collagen hydrolysates with an average particle size of 162.8 nm exhibit the best filling efficacy, imparting favorable organoleptic and physical properties to the leather. Herein, a method for preparing protein fillers, using chrome shavings as raw materials, was established, i.e., the dechromed collagen fibres (with a chromium content of approximately 33.6 mg/kg) were mixed with 2000% of water and adjusted to pH 3.0 with a small amount of sulfuric acid, and heated at 60°C with continuous stirring for 11 hours. After hydrolysis, the pH was adjusted appropriately to reuse it in the wet blue retanning filling process. The research outcomes have significant guiding implications for promoting the "internal circular economy" and sustainable development within the leather industry. Note de contenu : - EXPERIMENTS AND METHODS : Experimental materials - Dechroming of chrome shavings - Hydrolysis of dechromed collagen fibres - Performance of collagen hydrolysate as a retanning agent - Analysis and testing - RESULTS AND DISCUSSION : Preparation and performance analysis of dechromed collagen fibres materials - Influence of hydrolysis conditions on the fundamental characteristics of collagen hydrolysates - Correlation between the particle size of collagen hydrolysates and filling efficiency - Table 1 : Properties of the collagen hydrolysates - Table 2 : Physical and mechanical properties of the crust leather En ligne : https://drive.google.com/file/d/1hD0IMUh9EOcTIH7DeQDo-eDaYvoQEeci/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40933 [article]

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A novel recycling technology for chrome shavings : Application of non-swelling acids during dechroming process / Sadaqat Ali Chattha in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIX, N° 8 (08/2024)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIX, N° 8 (08/2024) . - p. 360-368 Titre : A novel recycling technology for chrome shavings : Application of non-swelling acids during dechroming process Type de document : texte imprimé Auteurs : Sadaqat Ali Chattha, Auteur ; Minghui Li, Auteur ; Xu Zhang, Auteur ; Piyu Peng, Auteur ; Chunxiao Zhang, Auteur Année de publication : 2024 Article en page(s) : p. 360-368 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie analytique Chrome -- Recyclage Cuirs et peaux -- Déchets -- Recyclage Déchromage Extraction (chimie) Récupération (Déchets, etc.) Sulfoniques, Acides Sulfurique, Acide Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : To separate and recycle collagen fibers and chromium from chrome shavings is important for the sustainable development of leather industry. However, the requirement of chromium content for a wide range of industrial applications of the recycled collagen fibers is limited to 50 mg/kg, which is challenging for the current dechroming methods. Hence, the goal of this work was to establish an efficient dechroming method to address this problem based on the OH-replacement and non-swelling acid application principles. In this study, the types of aromatic sulfonic acids and the parameters of the dechroming processes were optimized, and the tanning performance of the recycled chromium was investigated. The results indicated that disposal of the alkali treated chrome shavings with a mixed acids exhibited high dechroming extent and low extent of collagen hydrolysis, and the optimal ratio of sulfuric acid (20%) to optimized non- swelling acid-sulfone sulfonic acid was 7:1 at pH 1.0 and 25°C. The resultant collagen fibers retained their fiber structure and had a maximum hydrolysis extent of 10.6%, with a chromium content of 39.9 mg/kg. Additionally, the chromium in the dechroming filter liquor displayed good alkali precipitation property, and the chromium concentration of the precipitate’s supernatant satisfied the requirements for direct discharge, approximately 1.05 mg/L, and the recovered chromium exhibited good tanning performance. Therefore, the newly developed salt free chrome shavings treatment method is a promising resource recycling technology and may be helpful for the sustainable development of the leather industry. Note de contenu : - MATERIALS AND METHODS : Materials - Methods - Exploring the tanning performance of recycled chrome tanning agent - Analysis and testing - Scanning electron microscope analysis - RESULTS AND DISCUSSION : Chromium extraction - Utilization of products - Utilization of dechromed collagen fibers - Table 1 : Effect of acid types on filtration performance (min), moisture content (%) and dechroming extent (%) - Table 2 : Effect of sulfuric acid (20%, w/w) and SDPSA (50%, w/w) on filtration performance, moisture content, dechroming extent and extent of collagen hydrolysis DOI : https://doi.org/10.34314/brrhvf02 En ligne : https://drive.google.com/file/d/18NEdU3a_YjuWL6e-dbTQ9139bBWJRSSM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=41289 [article]

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