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A panoramic overview of the leather world market is given. The industrial tanning process is schematically
explained giving a general outline of how an animal skin is transformed into a durable material having many
different characteristics according to its specific future use. All the tanning industrial steps are overviewed starting
from soaking,...
Context in source publication
Context 1
... (29%), keratin (2%), elastin (0.3%) while non-struc- tural proteins are albumins, globulins (1%), mucins, mucoids (0.7%). As minor components, fats (2%) and other substances (0.5% inorganic components, 0.5 % pigments, etc.) are contained in the skin [6]. In Table 2 are reported the average amino acid composition of collagen and keratin (see also Fig. 1). The process, albeit its complexity, is very flexible and adaptable to the raw materials and the charac- teristics of the final products wanted. In Scheme 1 are reported only the tanning steps involving rele- vant chemical transformations of collagen; mechan- ical treatments such as fleshing or splitting are dis- cussed only in the ...
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Reasons to adopt Corporate Social Responsibility reporting by leather tanning companies must primarily be sought in the specific nature of the industry, where leather is a material from renewable sources, however part of its manufacture process might pose one of the gravest environmental hazards in the world. The tanning industry appears, therefore...
The leather industry transforms raw hides and skins into high-performance leather products. This transformation requires a high usage of chemicals. About 90% of all leather products are tanned by basic chromium sulphate tanning agents. The use of large quantities of tanning agent causes elevated chromium and sulphate concentrations in the wastewate...
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Citations
... The graphical representations for the pseudo-first-order and pseudo-second-order kinetics were used to derive the k 1, k 2 , q e , and correlation coefficients (R 2 ) [40]. At 25, 50, 75, (6) q e = K T ln a T + K T ln C e (7) ln q e − q t = ln q e − K 1 t and 100 ppm, a pseudo-first-order reaction rate was observed for the adsorption of Cr (VI). The model was evaluated by plotting ln (q e − q t ) against time which was shown in Fig. 13a. ...
In this study, a biodegradable spherical adsorbent bead was developed from eggshell (ES) and Bijoypur clay (BC) for the removal of hexavalent chromium from synthetic tannery wastewater. This Eggshell–Clay polymer composite (ES–BC) was made by incorporating them with PVA and alginate. To analyze the morphology and chemical composition of the adsorbent before and after the chromium adsorption, SEM, FTIR, XRD, and EDX were used. The impact of adsorption parameters such as adsorbent dosage (0.67–2.23 g/L), pH of the solution (1.5–9), contact time (10–240 min), initial Cr (VI) concentration (25–100 ppm), and solution temperature (25–65 °C), percentage clay in ES-BC adsorbent (0–40%) for Cr (VI) adsorption were investigated. The optimum value for adsorbent dosage, pH, contact time, initial Cr concentration, temperature, and clay to eggshell ratio was found 1.17 g/L, 1.5, 150 min, 58.2 ppm, 25 °C, and 80/20% respectively. The isotherm model was well-fitted to the Freundlich isotherm suggesting heterogeneous adsorption in multilayer on surface. The adsorption kinetics followed pseudo-second-order kinetics supporting the chemisorption process. Moreover, a decrease in enthalpy (H°) and negative Gibbs free energy (G°) with increased temperature indicated exothermic and spontaneous reaction. Therefore, this research investigated that the composite may serve as a viable option for treating Cr (VI) containing tannery effluent.
... Te pH then lowers, indicating the release of acid. Te ionization of neutral carboxyls, the ionization of positively charged amino (−NH 3+ ) groups, or even the hydrolysis of chrome itself may be the sources of this acid [19]. Neutralization, a crucial step in the production of leather, eliminates the leather's acidity and helps dyes penetrate the leather matrix. ...
... Neutralization, a crucial step in the production of leather, eliminates the leather's acidity and helps dyes penetrate the leather matrix. Sodium carbonate and sodium bicarbonate are among the chemicals used to assist the neutralization process and the pH of the foat is adjusted between 5.4 and 6.5 [19,20]. ...
Bio-based leather substitutes are an emerging class of ethically and environmentally responsible natural fabrics that are increasingly exceeding consumer aesthetic and functional expectations as an alternative to bovine and synthetic leathers. This literature review creates a clear and elaborative overview of conventional leather processing along with innovative potential bio-leather substitutes. Plant-driven, fungal-origin, bacterial-driven, and animal-origin bio-leathers are the current innovative research advances addressed in this literature. While traditional leather and its alternatives are sourced from animals and synthetic polymers, these renewable and sustainable leather substitutes are gained from bacterial cellulose, mycelium, plant cellulose, and animal cells using tissue engineering and other eco-friendly techniques. In conclusion, bio-based leather alternatives are eco-friendly, non-toxic, and sustainable and ultimately can substitute natural leather made by conventional processing.
... Currently, the world's biggest leather producers are located in Asia, with China being the leader of all prominent countries in the leather industry, followed by India and Hong Kong. . Among the EU countries, Italy is the leader in this sector, followed by France, while Germany, as the biggest importer of the EU, imports mostly from Turkey, China, and India [2,3]. The commercially used leather mostly comes from bovine hides with a substantial addition of goat hide and sheepskins. ...
... The high solubility causes rapid change in isoelectric point (swelling) and causing damage to the collagen and its side chains (Covington, 2009). Also, the use of sodium hydroxide (NaOH) cause swelling which is not reversible completely as compared to weak alkali such as calcium hydroxide whose solubility is 1.3g/L at 20 0 C (Beghetto et al., 2013). At the end, there was high change in the conformation of the collagen fibers which affect the stability of the collagen and lowering its shrinkage temperature (Nashchekina et al., 2021) The use of hydrogen peroxide causes the destruction of the hierarchical package of the collagen by breaking the (-C-O-C-) bond of galactose and fructose attached to hydroxylysine of collagen ( Figure 5). ...
... The similar wavenumber for amide I and amide II shows that, there were no C=O stretching vibrations for protein amide for amide I and stretching vibrations of C-N and in-plane bending of N-H for protein amide III The significant change of the side chains intensity for oxidative unhaired wet blue 90.83% as compared to raw skin sample 99.67% means that, there was significant destructions of glycoproteins and proteoglycans which form complex network with collagen (Nashchekina et al., 2021), and form hierarchical structure which determine the stability of the collagen, therefore, its destruction affect the physical features of the leather which are associated to the stability of collagen such as tensile strength and tearing strength (Beghetto et al., 2013) ...
Recently, more attention has paid to the reduction of environmental pollution due to leather processing, the beamhouse step especially unhairing part has been named as the one which contribute high pollutants in the total industrial waste. Therefore, different types of unhairing have been studied intending to reduce waste produced by unhairing step, however, no more findings on the influence of those alternatives to the collagen of the skin which determine the features of the leather. This study explores the impacts of those unhairing alternatives to the collagen of the skin. The shrinkage temperature values were lower as compared to that of raw skin sample, where oxidative unhaired skin, shows high difference (50.50C) from raw skin sample which was 64.90C. There were no significant differences in the hydroxyproline concentration between unhairing, this was due to triple helix structure of the collagen which make it more stable and not easily destroyed by unhairing chemicals. FT-IR results shows the differences in intensity (percentage) for side chain of collagen, where raw sample was 99.67%, oxidative was 90.83% while for conventional, hair saves and painting were 97.38%, 97.93% and 96.02% respectively. The stretching of N-H bond and bending for C-N bond for amide II, displays vibrations with wavenumber of 1519.20cm-1 for oxidative unhaired wet blue, as compared to other unhaired wet blue and raw skin sample which reads at 1539.20cm-1. The small differences in strength of the leather produced were associated with the change in the side chain intensity and conformation of collagen. The strength properties of the leather do not depend only on the concentration of the collagen but also on the proper packing of the collagen structures. The disturbance occurs to the hierarchical network of the collagen was reflected in the physical properties of the leather.
... The most common preservation systems act by reducing the bacterial activity by means of drying, salting or refrigerating the substrate as soon as possible since flaying. Among these methods, salting techniques are the most viable and, therefore, industrially widespread, although a high load of chloride ion is inevitably released into the waste water (Beghetto et al., 2013).There are developed methods of short-term preservation, which can be divided into physical and chemical (Valeika et al., 2017). Physical methods include: cooling with addition of ice; cooling in vacuum; irradiation or electron beam processing. ...
The study on investigation of the physico-mechanical properties of hide/skin (Sokoto red goat) using gamma ray irradiation as alternatives to salt curing preservation technique aims at converting flayed skin into the state of being resistant to putrefaction and it is accomplished by destroying active bacteria. The leather industry being one of the largest contributors to Nigeria’s economy requires more attention to be given to it. Despite its contribution to the economy of the nation, the methods of processing leather poses serious threat to the environment. The Salt preservation, the conventional method of preserving skin is practiced by most tanners and it employs approximately 40-50% sodium chloride which is subsequently removed into the environment during soaking operation and this pollutes the environment. To overcome the limitation of such method, an eco-friendly method was introduced, which is the irradiation (Gamma ray) method which serves as a safer and ecofriendly alternative technique of preservation. The type of tanning method applied after preservation is the vegetable tanning method using the Divi-divi(Caesalpinia coriaria) pods which is also eco-friendly. From the research carried out, the leather preserved using gamma had 21.878 N/mm2 at 300Gy, 3.27 Kg/cm2 at 300Gy, 0.33mm at 350Gy, 75oC at 200Gy, and 0.537g/cm3 at 150Gy which are the highest values for tensile strength, resistance to compression, indentation index, shrinkage temperature, and apparent density respectively as compared to the salt cured samples which had 23.963 N/mm2, 4.50 Kg/cm2, 0.23 mm 72oC, and 0.515 g/cm3 values for tensile strength, resistance to compression, indentation index...
... In fact, this industry is able to convert a by-product of the food industry into a noble material which otherwise should be disposed into waste. 10 Leather industry has to deal with these challenges and has to assume responsibilities in local and national development. Tannery processes are characterized by the use of significant quantities of chemicals, energy, and water. ...
Reasons to adopt Corporate Social Responsibility reporting by leather tanning companies must primarily be sought in the specific nature of the industry, where leather is a material from renewable sources, however part of its manufacture process might pose one of the gravest environmental hazards in the world. The tanning industry appears, therefore, as a sector compiling CSR reports expected to confirm its environment-friendly actions. The purpose of this research is to examine and understand CSR roles and diffusion in the small and medium enterprises of the leather tanning industry in Catalonia (Spain), especially in relation with the adoption of other management systems. It identifies the most distinguished CSR practices, procedures and metrics and the profiles of companies more prone to adopt them. We used a qualitative approach to fulfill this aim. Results show that leather companies are familiar with CSR practices, but there is further scope for improvement in terms of formalization of CSR procedures and measurement systems. Results show that the majority of socially responsible practices are related to environmental issues and consequently there is a relation between CSR and the application of environmental management systems. The analysis reveals that the management of CSR activities improves with the diffusion of knowledge on CSR practices.
... This is followed by the water-based alkaline solution where calcium hydroxide and copper salts have been dissolved to remove the hair fibres definitively and to give a first exposure to permanent preservative compounds to the hides. However, from treatment to minimise the impact or recovery of alkaline solutions, particular research looks at the economic and environmental advantages of such practices (Beghetto et al., 2013). ...
Para este trabajo se han realizado adaptaciones de las técnicas más destacadas en los antecedentes de tratamientos químicos e hidrotérmicos destinados a la extracción proteica para distintas fuentes derivadas de las faenas alimenticias, a gran escala actualmente; de las cuales se aprovecha las propiedades adherentes basadas principalmente en la queratina, compuesto orgánico con trazas mayores al 90% en plumaje y pelaje animal. Los cuales son procesados químicamente para obtener un aglutinante orgánico dosificado en cuatro mixturas A, B, C y D, en las cuales varía el porcentaje y origen del pegante como también la porción de los áridos minerales residuales pulverizados calcáreos (marmolina) y cerámicos (ladrillo) con los cuales, amasados a mano, se forma una pasta homogénea que se modela en moldes normados para proceder al cálculo de sus propiedades físicas tales como coeficiente de absorción de humedad ambiental, dureza superficial y resistencia mecánica máxima a esfuerzos de compresión y flexión.AbstractFor this work, adaptations have been made of the most outstanding techniques in the history of chemical and hydrothermal treatments aimed at protein extraction for different sources derived from the food industry, on a large scale at present; of which the adhesive properties based mainly on keratin, an organic compound with traces of more than 90% in animal plumage and fur, are taken advantage of. These are chemically processed to obtain an organic binder dosed in four mixtures A, B, C and D, in which the percentage and origin of the glue varies as well as the portion of the residual pulverised calcareous (marble) and ceramic (brick) mineral aggregates with which, The homogeneous paste is then moulded in standard moulds to calculate its physical properties, such as the coefficient of absorption of ambient humidity, surface hardness and maximum mechanical resistance to compressive and flexural stresses.
... Tanned leather can be obtained from different sources, bovine tanning comprising 63% of the total production, followed by sheep (17%) and others, such as goat, pigs, rabbits and reptiles (20%) [3]. The main objective of the tanning process is the stabilization of collagen and other proteins present in animal skins by cross-linking agents, such as metals and/or polyphenols [4]. Chromium salts have special relevance, which have been used as an effective agent to stabilize the degradation of the material and which confers to leather valuable properties for different applications [5]. ...
Collagen-based polymers and their blends have attracted considerable interest for new materials development due to their unique combination of biocompatibility, physical and mechanical properties and durability. Leather, a modified natural biopolymer made from animal rawhide and the first synthetic collagen-based polymer known since the dawn of civilization, combines all these features. Rawhide is transformed into leather by tanning, a process in which the collagen is cross-linked with different agents to make it stronger and more durable and to prevent its decay. Research on the development of environmentally friendly procedures and sustainable materials with higher efficiency and lower costs is a rapidly growing field, and leather industry is not an exemption. Chrome-tanned and vegetable-tanned (chromium-free) shavings from the leather industry present a high content of organic matter, yet they are considered recalcitrant waste to be degraded by microbiological processes like anaerobic digestion (AD), a solid technology to treat organic waste in a circular economy framework. In this technology however, the solubilisation of organic solid substrates is a significant challenge to improving the efficiency of the process. In this context, we have investigated the process of microbial decomposition of leather wastes from the tannery industry to search for the conditions that produce optimal solubilisation of organic matter. Chrome-tanned and chromium-free leather shavings were pre-treated and anaerobically digested under different temperature ranges (thermophilic–55 °C-, intermediate–42 °C- and mesophilic–35 °C) to evaluate the effect on the solubilisation of the organic matter of the wastes. The results showed that the presence of chromium significantly inhibited the solubilization (up to 60%) in the mesophilic and intermediate ranges; this is the fastest and most efficient solubilization reached under thermophilic conditions using the chromium-free leather shaving as substrates. The most suitable temperature for the solubilization was the thermophilic regime (55 °C) for both chromium-free and chrome-tanned shavings. No significant differences were observed in the thermophilic anaerobic digestion of chromium-free shavings when a pre-treatment was applied, since the solubilisation was already high without pre-treatment. However, the pre-treatments significantly improved the solubilisation in the mesophilic and intermediate configurations; the former pre-treatment was better suited in terms of performance and cost-effectiveness compared to the thermophilic range. Thus, the solubilisation of chromium-free tannery solid wastes can be significantly improved by applying appropriate pre-treatments at lower temperature ranges; this is of utter importance when optimizing anaerobic processes of recalcitrant organic wastes, with the added benefit of substantial energy savings in the scaling up of the process in an optimised circular economy scenario.
... The leather industry transforms skins into leather through a series of processes and applying different chemical products [Covington and Wise, 2015]. Tanning is the main process, where collagen in skins is stabilized against heat, enzymatic activity and putrefaction [Beghetto et al., 2013;Zeiner et al., 2011] by a applying a tanning agent. Tanning carried out by applying basic chromium sulfate salts (BCS) is the most used tanning technique worldwide, nearly 90%, as it provides leather with desirable physical-mechanical properties such as excellent hydrothermal stability, better dying capacity and softness [Fei and Liu, Evaluation of Environmental Performance of Chrome-Free Tanning Techniques of Paiche Skins (Arapaima gigas) Jalinee Blas García 1 , Liliana Marrufo Saldaña 2* , Julio Barra Hinojosa 2 2016; Kanagaraj et al., 2008]. ...
The leather production from paiche skins (Arapaima gigas) has recently grown in Peru, as this allows to add value and earnings from this Amazonian aquaculture waste. The development of this process requires that the tanning techniques could preserve environment as these are meant to take place in Amazonian zones. The present study evaluated the environmental performance of two chrome-free tanning techniques of paiche skins compared with traditional chrome tanning technique, developed at pilot scale by CITEccal Lima. The evaluation was carried out using environmental performance indicators (EPI), analyzed and compared using the Grey Clustering method, identifying coefficients (σ) respecting to the stablished classes in the study (λ1: Good, λ2: Regular, λ3: Deficient). As result, the two chrome-free tanning techniques shown a better environmental performance than the traditional chrome tanning technique (σ: 0.54, class λ2). The optimized tanning technique applying phenolic compounds had the best environmental performance (σ: 0.98, class λ1), and its values for each environmental performance indicator per 1000 kg of initial processed paiche skin were: 30.0 m3 for water consumption, 815.0 kg of chemical products applied, 2022.7 kWh for energy consumption, 105.5 kg of solid wastes; and from wastewater characterization: 2780.9 mg/L for BOD, 11682.9 mg/L for COD and non-detectable chromium. Based on these results, its transfer is recommended, including a wastewater treatment system and environmental management measures implementation.
... Обработка кожи включает операции дубления и отделки, в которых, среди прочего, активно используются кислоты, основания, ферменты, соли и красители [5][6][7]. Потенциально химические вещества, используемые в этих процессах, приводят к значительному загрязнению окружающей среды стоками и твердыми отходами, а также делают готовую кожу опасной как для окружающей среды, так и для здоровья человека [8,9]. Уровни концентрации некоторых элементов в коже и изделиях из нее вызывают озабоченность у регулирующих органов здравоохранения и экологов [10][11][12][13]. ...
