Article

Application of gelatin extracted from chrome shavings for the glazed finishing of leather

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Abstract

The objective of this work was to ascertain the performance of extracted gelatin from dechromed leather shavings as a coating in the finishing of leather. Gelatin is a protein-based material isolated from chrome-tanned collagenic wastes. A comparison between a commercial protein-based product, extracted gelatin and a mixture of extracted gelatin/glycerol was carried out. Based on the results obtained in previous studies, two fixing agents were used to fix the finishing: 5-ethyl-1-aza-3, 7-dioxabicyclo [3,3,0] octane (oxazolidine II) and ethylene glycol diglycidyl ether (EGDE). The mixture gelatin/glycerol (using glycerol as a plasticiser) presented satisfactory results, compared with the commercial product, for the abrasion, gloss and flex resistance, although a poor performance under wet rub fastness (assessment of 1 on the grey scale (ISO 105-A02, A03) and adhesion tests were found due to the hygroscopic nature of glycerol. The formulation for potential further studies was the extracted gelatin fixed with EGDE, which showed the best performance on dry rub fastness (4-5 on the grey scale) and finish adhesion, and a good performance on resistance to abrasion and to flex (low loss of finishing and no cracking observed). The results confirmed the potential for gelatin, obtained from chrome shavings, to be used as a leather finishing agent

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... Dechromed collagen obtained from chrome-containing leather solid wastes have been applied in leather process, such as retanning filling materials [112][113][114] and finishing agents [115,116], papermaking, such as sizing agents, flocculant and surfactant [117,118], agricultural production, such as liquid mulch film, amino acid foliar fertilizer, emulsifier of pesticides [119][120][121] and biomedical field [122][123][124]. ...
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Leather making is the process of converting raw hides into leather. Amounts of solid waste containing hazardous and high value components are generated during this process. Therefore, the elimination of the potential pollution and resource utilization of leather solid waste are the primary research hotspots. Herein, we comprehensively review the recent advances in the resource utilization of leather solid waste generated from chrome tanning including the utilization of tannery hair waste, untanned solid waste, chrome-containing leather solid waste, tannery sludge and finished leather waste, emphasizing on the general and novel utilization approaches. Finally, the remaining challenges and perspectives were summarized, in order to accelerate the development of resource utilization of leather solid waste.
... 52 However, industrial waste such as gelatin recovered from waste leather tanned with chromium is also a noteworthy source. [53][54][55][56][57][58] Films can also be produced with gelatin extracted from fish skin 59,60 and from chicken bones too. 61,62 Films made from corn starch and gelatin were studied, comparing commercial gelatin and gelatin recovered from chrome leather waste, and evaluating the drying conditions used for film production. ...
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... 12 Therefore, other alternatives that deal with wastes generated in this industry should be explored. 10,[13][14][15] Hydrolysis is an alternative method for CTLW use since it allows the extraction of two main fractions from it: protein and chromium. CTLW hydrolysis dates back to the 70's 16 and its broader development started in the 90's. ...
Article
Among the reuse and/or disposal possibilities for chromium tanned leather waste (CTLW), one in particular stands out: hydrolysis. This process not only allows chromium recovery, but also the extraction of its protein, as collagen hydrolysate or as gelatin. CTLW hydrolysis has been performed for decades. However, industrial application of this important alternative has not been widespread. Thus, this review presents how CTLW alkaline hydrolysis has been evolving over the years; how the process can be adjusted to increase protein extraction yield and to produce better quality products. Finally, it reviews in which areas its products have already been tested. Here, researchers may find practical process information that might allow them to focus on the most important current issue for CTLW hydrolysis: how to upgrade this process to an industrial scale.
... The use of products resulting from alkaline hydrolysis has also been studied. The hydrolyzed protein fraction could be used as fatliquour, surfactant and filler for leather manufacture, especially after modification with formaldehyde, glutaraldehyde, acrylic acid, acrylamide derivates, methacrylic acid, polyurethane, enzymes and others [33][34][35][36][37][38]. Also, the hydrolyzates are proposed to prepare fertilizers, animal food, surfactants, adhesives and films [39][40][41][42][43]. ...
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The leather tannery industry produces a significant amount of solid and hazardous wastes. Chromium-containing wastes like tanned shavings used to be incinerated in order to recover energy. The incineration process generates ashes that must be disposed of. This paper is a report on the results of the evaluation of technological properties and environmental compatibility of products made of alumina and ashes from incinerated chrome tanned shavings. The raw materials, tannery ashes and alumina were mixed together in different proportions. The ceramic bodies were molded using a hydraulic press and fired with a heating rate of 100 K/h until 1400 degrees C for 4 h in a muffle furnace. The ceramic specimens were characterized regarding physical, mechanical and thermal properties. Leaching tests, according to Brazilian, German and Dutch regulations, were performed on ceramic bodies containing different additions of ash. Results show that the ceramic materials produced are acceptable for refractory applications.