Cyclic dechroming process for chrome shavings by coordination substitution reaction and photocatalysis / Yuling Tang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 11 (11/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 11 (11/2014) . - p. 380-388 Titre : Cyclic dechroming process for chrome shavings by coordination substitution reaction and photocatalysis Type de document : texte imprimé Auteurs : Yuling Tang, Auteur ; Hu Zaiyin, Auteur ; Huitun Liu, Auteur ; Hu Wei, Auteur ; Wang Ru, Auteur Année de publication : 2014 Article en page(s) : p. 380-388 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chrome Déchets industriels -- Elimination Déchromage Ethylène diamine tétra acétique L'EDTA (Ethylène Diamine Tétra Acétique), ou acide éthylène diamine tétraacétique, est un acide diaminotétracarboxylique de formule C10H16N2O8. L'EDTA comporte six sites basiques, quatre correspondant aux bases conjuguées (carboxylates) des fonctions carboxyliques et deux correspondant aux fonctions amines. Ces sites basiques sont également des centres ligands, faisant de l'EDTA un ligand hexadentate (ou parfois tétradentate, lorsque seuls les sites carboxyliques sont utilisés). C'est d'ailleurs sa principale caractéristique, son fort pouvoir chélatant (ou complexant) par lequel il forme des complexes métalliques très stables, ce qui en fait un traitement en cas d'intoxication aux métaux lourds comme le plomb, avec une concentration adaptée (Voir Applications et chélation). Dans les complexes, l'EDTA est lié aux cations métalliques sous la forme d'une de ses bases conjuguées9. Extraction (chimie) Photocatalyse Sulfurique, Acide Tannage -- Déchets Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The cyclic dechroming process for chrome shaving by method of coordination substitution reaction and photocatalysis was investigated. Using EDTA (ethylene diamine tetraacetic acid) as dechroming agent and NaOH as recovery agent, the process conditions were optimized through the orthogonal tests. The removal efficiency of chrome from chrome saving was 98,88% when dechroming was undertaken in 0.03mol/L EDTA solution at 50°C and pH 6.0 for 14 days with stirrung and then treated in the same solution under ultraviolet (145 W, 254 nm) for 8 days, and the loss of collagen was 5.31%. The chrome was separated from the dechroming solution as Cr(OH)? precipitate by adding NaOH into the dechroming solution (conc. og NaOH=1.00mol/L) and stirring at 70°C for 1d. The solution containing EDTA was reused for dechroming again after filtering and adjusting pH to 6.0 by sulfuric acid and the removal efficiencies of chrome were all more than 97% in triplicate trials. The structure of collagen after chrome extraction was characterized by SEM and FT-IR. The results indicated that the triple helix structure of collagen was well preserved. The thermal stability of collagen after chrome extraction was characterized by DSC; the results indicating that it was in conformity with rawhide. The dechroming process without strong acid and alkali can prevent collagen from hydrolisis. A certain amount of Cr(VI) appeared by adding alkali in precipitating Cr and recovering EDTA. However, Cr(VI) was reduced to Cr(III) when pH of recovered EDTA solution was ajusted to 6.0 by adding sulfuric acid. This kind of closed recycling dechroming technology can reuse dechroming process. Note de contenu : - EXPERIMENTAL : Materials and chemicals - Equipment - Experimental procedure. Dechroming through coordination substitution reaction and photocatalysis - Observation of structural change of collagen - Optimization of dechroming process by orthogonal test - Recovery of EDTA in dechroming Solution - Cyclic dechroming experiment - Analysis method - RESULTS AND DISCUSSION : EDTA dechroming through coordination substitution reaction and photocathalysis - Physico-chemical characteristics of collagen before and after dechroming - Observation of structural change of collagen - The thermostability change of collagen thermal stability - Mechanism of EDTA Dechroming through coordination substitution reaction and photocatalysis - Optimization of dechroming process by orthogonal test - Recovery of EDTA in dechroming solution - Cyclic dechroming experiment En ligne : https://drive.google.com/file/d/1B6mJIpCCQa2dDv83UJ9qOnrAijAY3qKI/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22279 [article]

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Effect of leather chemicals on Cr(III) removal from post tanning wastewater / Yuling Tang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 3 (03/2018)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIII, N° 3 (03/2018) . - p. 74-80 Titre : Effect of leather chemicals on Cr(III) removal from post tanning wastewater Type de document : texte imprimé Auteurs : Yuling Tang, Auteur ; Jianfei Zhou, Auteur ; Yunhang Zeng, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2018 Article en page(s) : p. 74-80 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Coagulation Composés complexes Cuirs et peaux Déchets industriels -- Elimination Eaux usées -- Epuration Eaux usées -- Teneur en chrome trivalent Polyacryliques Produits chimiques Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The effect of typical leather chemicals on removal of Cr(III) from tannery post tanning wastewater by PAC coagulation was investigated. It was found that all the leather chemicals investigated could form complexes with Cr(III) through their anionic hydrophilic groups. The determinations of fluorescence quenching titration indicated that the Cr(III)-complexing ability of these anionic hydrophilic groups was in the sequence of phenolic hydroxyl of vegetable tannins and syntans > carboxyl of acrylic resins > sulfonic acid group of fatliquors and dyes. The complexes formed had higher hydrophobicity because a part of anionic hydrophilic groups of leather chemicals were blocked. The Cr(III) complexes with vegetable tannins, syntans and dyes were in the form of hydrophobic colloid or particle due to both the blocking effect of hydrophilic groups and the strong hydrophobicity of benzene ring, which favored the removal of Cr(III) from post tanning wastewater by coagulation (removal extent 82%-99%). But the Cr(III) complexes with acrylic resins existed as water-soluble pieces, probably because a part of free carboxyl group still kept on the polymer chain at reaction equilibrium, and acrylic resins had no structure/group with hydrophobicity as strong as benzene ring. As a result, Cr(III) was difficult to be removed from wastewater when acrylic resins existed (removal extent <60%). That is, the formation of Cr(III)-acrylic resin complexes is the major obstacle in removing Cr(III) effectively from post tanning wastewater. Note de contenu : - EXPERIMENTAL : Materials - Preparation of simulated post tanning wastewater - Removal of Cr(III) and TOC from the simulated post tanning wastewater by coagulation - Analysis of Cr(III)-binding ability of model post tanning chemicals - RESULTS AND DISCUSSION : Effect of status of Cr(III) complexes on removal of Cr(III) from wastewater - Cr(III)-binding abilities of model post tanning chemicals En ligne : https://drive.google.com/file/d/1U4KjsYPeV6p_gmwFNhu_sKQ9PlhYvsev/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30273 [article]

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Synthesis and urea-loading of a novel biosuperabsorbent polymer based on leather waste / Hu Zaiyin in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 2 (03-04/2015)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 99, N° 2 (03-04/2015) . - p. 51-57 Titre : Synthesis and urea-loading of a novel biosuperabsorbent polymer based on leather waste Type de document : texte imprimé Auteurs : Hu Zaiyin, Auteur ; Yi Shouhong, Auteur ; Hu Wei, Auteur ; Yuling Tang, Auteur ; Wang Ru, Auteur Année de publication : 2015 Article en page(s) : p. 51-57 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorbants et adsorbants Copolymère acide acrylique acrylamide Copolymères -- Synthèse Cuirs et peaux -- Déchets -- Recyclage Greffage (chimie) Humidité -- Absorption:Eau -- Absorption Urée Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In order to develop an eco-friendly polymer, a novel superabsorbent polymer was synthesized by grafting the alkaline hydrolysis product of Leather waste (LW) to a copolymer of acrylic acid (AA) and acrylamide (Afv1)(PLW-g-(AA-co-AM) with microwave method assistance. The morphology of the samples was examined by scanning electron microscopy (SEM). Through a single factor experiment, various factors were explored which may affect the water absorption of such a superabsorbent polymer du ring preparation. The results showed that the optimum technological conditions of synthesizing PLW-g-(AA-co-AM) were : dosage of LW 15wt.% of total monomer mass, cross-linking agent 0.06wt.°/0 of monomer mass, neutralization degree 75%, AA: AM= 6 :1, initiator 0.6wt.% of monomer mass. According to this procedure, the PLW-g-(AA-co-AM) with a water-absorbency of 1191.5g/g and salt-absorbency of 94.4g/g was obtained. The product was used as adsorbant for urea, the urea load rate reached 87.76% when the concentration of urea was 10g/L. Meanwhile, the release of urea from the loaded PLW-g-(AA-co-AM) in deionized water exhibited specific release properties. Note de contenu : - EXPERIMENTAL PROCEDURE : Materials - Swelling measurements : Tea-bag method - Instrumental analysis - RESULTS AND DISCUSSIONS : Optimization of the grafting conditions - Loading and release of urea En ligne : https://drive.google.com/file/d/1PiVWaSmKFsQTY_zL8lgdvGzkXTi9x7V3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23741 [article]

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Tannery wastewater treatment : conventional and promising processes, an updated 20-year review / Jun Zhao in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 4 (Année 2022)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 4 (Année 2022) . - 22 p. Titre : Tannery wastewater treatment : conventional and promising processes, an updated 20-year review Type de document : texte imprimé Auteurs : Jun Zhao, Auteur ; Qinglian Wu, Auteur ; Yuling Tang, Auteur ; Jianfei Zhou, Auteur ; Hongguang Guo, Auteur Année de publication : 2022 Article en page(s) : 22 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adsorption Coagulation Cuirs et peaux -- Industrie -- Aspect de l'environnement Eau -- Epuration -- Traitement biologique Eaux usées -- Analyse Eaux usées -- Décontamination Eaux usées -- Recyclage Electrochimie Filtration Floculation Oxydation Tannage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Mismanagement of various wastes especially waste water produced by tanning processes has caused serious environmental problems and ultimately impaired human health. Constant efforts have been making to alleviate the pollution of tannery wastewater (TWW), yet terminal treatment still takes dominance. In this review, research on TWW treatment from 2000 to 2021 was summarized, and main methods such as coagulation and flocculation, adsorption, biological treatment, membrane filtration, advanced oxidation process were briefly discussed. More detailed introduction was given to the method of electrochemical treatment since it has excellent performance such as environmental friendliness and high efficiency, hence attracting more and more research attention in recent years. In view of the harsh physi-chemical conditions of TWW, integrated or combined treatment methods are accordingly recommended with better performance and multi-function, however comprehensive studies on optimization of methods combination and cost-effectiveness are needed. The certain issues that the residue Cr in treatment sludge and high salinity in effluent still remain were put forward in this work and potential solutions were provided. Moreover, this review proposed the perspective that realizing multi-function, recycling, and intensification should be the developing direction for future TWW treatment. This review is expected to provide a general guide for researchers who aspire to ameliorate TWW pollution problems and understand various methods utilized in this field. Note de contenu : - CHARACTERISTICS OF TANNERY WASTEWATER - TREATMENT FOR TANNERY WASTEWATER : Flocculation and coagulation - Biological treatment - Membrane filtration - Advanced oxidation processes - Electrochemical treatment - Adsorption - Integrated methods - PROBLEMS TO BE SOLVED AND POTENTIAL SOLUTIONS - TWW TREATMENT FOR THE FUTURE - Table 1 Direct discharge standard of treated TWW in different countries - Table 2 Qualitative comparisons of all TWW treatment methods - Table 3 Selected reports (2010–2020) related to combined/integrated methods to treat real or synthetic TWW DOI : https://doi.org/10.1186/s42825-022-00082-7 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-022-00082-7.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37577 [article]

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