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Almost 90% of the leather produced globally uses basic chromium sulfate (BCS) as a tanning agent for permanent stabilization of collagen protein that is produced by reducing hexavalent chromium into trivalent chromium using either organic or inorganic reducing agents. Even though organic reduction using molasses paves a greenway toward BCS manufacture, the quantum of molasses available is insufficient for BCS production to meet global needs. On the other hand, India generates approximately 500 million tonnes of agricultural waste every year, majorly comprising crop residues of rice and wheat that are burned every year to battle surplus amounts of waste. Herein, we report a new method for BCS production using polysaccharide-rich wheat bran (WB) as a reducing agent, making it a facile method to tackle molasses non-availability and burning surplus crop residues. The offer level of WB required for BCS production was optimized to match BIS norms, and the prepared product was evaluated as a tanning agent in leather production. The mechanism of chromium reduction by WB studied using IR and NMR techniques revealed polysaccharide oxidation into aldehyde and carboxylic acid following a classic redox reaction. Additionally, a method for the synthesis of metal complexes of definite morphology using agro-industrial wastes as templates is also proposed in this work. The calculated product cost also confirmed that using WB as a reducing agent in BCS production is economically feasible. [ABSTRACT FROM AUTHOR]

A painted wooden shield from the 16th century, commonly traced back to the famous Lepanto Battle (1571), was investigated by a multi‐analytical approach to identify its manufacturing process and shed light on its cultural provenance. The typology is coherent with both the Christian and Ottoman armies and does not allow for an attribution. Radiocarbon dated the shield to two time intervals (1470–1525, 1580–1625, at 68% level of probability), compatible with the date of the Battle of Lepanto. Optical and Scanning Electron Microscopy, Attenuated Total Reflectance, External Reflection Fourier Transform Infrared, micro‐Raman and Energy Dispersive X‐ray Spectroscopy, and histochemical and shrinking temperature tests were used to characterize the artefact. The shield resulted to be made of softwood panels, covered by a stratigraphy of flax fibres, cattle skin, and a painting preparation layer of hydromagnesite. Adhesion was ensured by bone glue. Oblique, red, and cinnabar stripes alternating on the white preparation are visible on the front of the shield, whereas a homogeneous dark paint covers the back. None of the raw materials was informative by themselves, but the unusual presence of the hydromagnesite could be crossed with the geographical context, resulting in a promising outcome for future isotopic and trace element studies. [ABSTRACT FROM AUTHOR]

Tanneries generate copious amounts of potentially toxic sludge and effluent from the processing of skins and hides to leather. The effluent requires remediation before discharge to protect the receiving environment. A range of physicochemical methods are used for pre- and post-treatment, but biological secondary remediation remains the most popular choice for the reduction of the organic and macronutrient fraction of tannery effluent. This review provides an update and critical discussion of biological systems used to remediate tannery effluent. While the conventional activated sludge process and similar technologies are widely used by tanneries, they have inherent problems related to poor sludge settling, low removal efficiencies, and high energy requirements. Treatment wetlands are recommended for the passive polishing step of beamhouse effluent. Hybrid systems that incorporate anoxic and/or anaerobic zones with sludge and/or effluent recycling have been shown to be effective for the removal of organics and nitrogenous species at laboratory scale, and some have been piloted. Novel systems have also been proposed for the removal and recovery of elemental sulfur and/or energy and/or process water in support of a circular economy. Full-scale studies showing successful long-term operation of such systems are now required to convince tanneries to modernize and invest in new infrastructure. [ABSTRACT FROM AUTHOR]

For commercial leather processing, chrome tanning is the most used approach but it significantly contributes to environmental pollution. Vegetable tannins, which are large polyphenolic compounds, form strong interactions with proteins and carbohydrates, thereby enhancing the adaptability and value of vegetable-tanned leather as well as reducing environmental impact. In this study, vegetable tannins were extracted from the leaves of Guava plants (Psidium guajava) using ethanol as the solvent, facilitated by ultrasound. Extracted tannins were quantified using the Folin–Ciocâlteu reagent with ultraviolet-visible spectroscopic method. Ultrasound enhanced the extraction process producing a high yield in less time due to its mechanical, thermal, and cavitation impacts. The extracted tannins were characterized by a variety of spectroscopic techniques, including Proton (1H) Nuclear magnetic resonance, Fourier-transform infrared, and ultraviolet-visible spectroscopy. The effect of various process variables, such as temperature, solid-liquid ratio, ultrasonic power, extraction period, and powder fineness, were also investigated to optimize the extraction process. Finally, the extracted tannins were employed in leather tanning processes to assess their potential as tanning agents. The extracted tannins ensured uniform diffusion of tannins, improved thermal stability and reduced the number of tannins in effluent by 68% making it an environmentally friendly leather tanning process.

Environmental pollution caused by wastes generated from chrome tan is a major concern nowadays. This study aimed to develop an eco-friendly alternative tanning agent using graphene oxide (GO) based nanocomposite materials. GO was synthesized by a new approach with modification of the Hummers method. Two types of GO-based nanocomposites, GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were prepared by adding TiO2 nanoparticles and polyethylene glycol (PEG) as surface modifiers. They were successfully applied to leather tanning processes at different concentrations (2%, 4%, and 6%). Both synthesized GO, GO-nanocomposites, and the resulting tanned leathers were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Fourier-transform Infrared Spectroscopy (FT-IR). Different physico-mechanical properties of leathers tanned with nanocomposites were evaluated and the results were compared with chrome-tanned leathers. The tensile strength of chrome-tanned leather was 223 (kg/cm) whereas the maximum tensile strength was found at 228 (kg/cm) and 233 (kg/cm) in 6% GO-TiO2 and GO-TiO2-PEG tanned leathers respectively. The environmental pollution impact of the effluents generated by the new tanning process was assessed. The COD of effluents generated from chrome tanning was 4800 ppm which was significantly reduced to 2400-1440 ppm and 2880-1920 ppm when GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were applied in leather tanning respectively. The TDS and BOD were found at 183.8 and 200 ppm in conventional chrome-tanned wastewater which were significantly reduced to the range of 47.5-18.3 and 100-50 ppm respectively in liquid wastes obtained from the GO-composite tanning process. The maximum reduction of COD, BOD, TDS, and TSS in leather waste liquid was found with the application of 2% GO-nanocomposites in tanning. The results revealed that leathers tanned with nanocomposites possess characteristic properties which were very similar to those observed in chrome-tanned leathers whereas the new tanning agents drastically reduced the intensity of pollutants in leather effluents. The application of new nanocomposites in the leather tanning process is an innovative effort. This new nanocomposite-tanning method showed minimal consequences regarding environmental pollution with the generation of less toxic effluents from the respective tanning process.

Objective: Sexual minority men experience disproportionately elevated rates of skin cancers, likely driven by excess ultraviolet radiation exposure--namely through tanning behaviors. However, limited integrated theoretical models exist to explain sexual minority men's elevated skin cancer risk. The aim of the current study is to further test and refine an integrated theory of skin cancer risk behaviors among sexual minority men by incorporating minority stress into the integrated health behavior model of tanning. Method: The study employed a parallel mixed methods design, with a Phase 1 qualitative stage (N =30) and a Phase 2 quantitative stage (Model 1: N =320; Model 2: N = 319). In both phases, participants were sexual minority men, equally stratified as those with versus without recent tanning exposure and were recruited from across the United States. Results: Qualitative and quantitative data supported the overall integrated model, with some quantitative paths varying depending on the tanning behavior outcome. Overall, appearance-related motives to tan and beliefs that tanning regulates affect emerged as the most consistent proximal predictors. Minority stress significantly predicted holding more positive attitudes toward tanning as an effective affect regulation strategy. Conclusions: The results from this mixed methods study support the inclusion of minority stressors into the adapted integrative health behavior model of tanning. Replication within prospective designs would strengthen the evidence for this model, which may be helpful in guiding future skin cancer prevention programs tailored to sexual minority men. [ABSTRACT FROM AUTHOR]

The aim was to evaluate the quality of the sheep skin of different sex classes submitted to different levels of feed restriction. Sheep without defined racial pattern of different sex classes (15 non-castrated males, 15 castrated males and 15 females), with initial body weight of 18.1 ± 0.4 kg and mean age of 90 days were distributed in a factorial 3 × 3, with three sex classes and 3 levels of feed restriction (ad libitum intake and restricted intake at 70 and 80%), with 5 repetitions. After slaughter, the skins were collected for physical–mechanical tests. The effect of the sex classes x levels of dietary restriction interaction was observed for transverse thickness and longitudinal rupture elongation (p < 0.05). Animals fed ad libitum had greater longitudinal transverse thickness (p < 0.05). Animals fed ad libitum and 70% feed restriction showed greater transverse elongation at break (p < 0.05). As for the difference between sex classes in the transverse thickness variable for tearing strength, the interaction sex classes x levels of feed restriction for transverse thickness, longitudinal thickness, transverse tearing strength and longitudinal tearing strength occurred (p < 0.05). Feed restriction reduces the physical quality of the skin of sheep of different sex classes, and the use of castrated male sheep in positive energy balance is recommended to obtain leather with greater thickness, longitudinal rupture elongation and transverse tear strength. [ABSTRACT FROM AUTHOR]

This study explored the potential application of polyphenols from Pinus halepensis bark in leather tanning. The primary objective was to characterize these polyphenols. The extraction and atomization processes proved efficient, reducing moisture content to 7.4%, increasing tannin content from 26.2% to 45.1%, and reducing insoluble substances by 77.5%. High-performance liquid chromatography (HPLC) coupled with mass spectrometry identified and quantified various polyphenolic compounds, including (+)-catechin, (+)-taxifolin, protocatechuic acid, and procyanidin B2. Notably, tannic catechin dimers were detected. Lignin was effectively removed through filtration. Concentrations of protocatechuic acid, (+)-catechin, (+)-taxifolin, (−)-epicatechin, and procyanidin B1 were significantly higher in the extract than in the powder, with the extract showing 1214.3 mg/kg of protocatechuic acid, 2098.0 mg/kg of (+)-catechin, 4017.0 mg/kg of (+)-taxifolin, 2163.0 mg/kg of (−)-epicatechin, and 917.0 mg/kg of procyanidin B1. [ABSTRACT FROM AUTHOR]

Industries play a substantial role in contaminating the freshwater sources. This study was performed to appraise the potential of biochar activated with 85% phosphoric acid was used as chemisorbent for the removal of Chromium III and VI (Cr III and VI)) and desorbed chromium was utilized for replacing the conventional basic chromium sulfate to ensure circular economy. In our previous studies, the factors for biosorption of Cr were optimized through Box–Behnken model under Response Surface Methodology. Batch adsorption studies revealed that the optimum conditions for maximum Cr (VI) biosorption by activated biochar is pH = 2, biosorbent dose: 1%, biosorbent size: 1 mm, solute concentration: 985 mg L−1 and reaction time 35 h. Based on these results a column experiments were carried out and flow rate was optimized as 0.5 ml m−1 where prominent "S" shaped breakthrough curves were noticed. The predicted values under Thomas model for the adsorption of Cr was 3827.2 µg g−1, which was in close agreement with experimental value of 3566.1 µg g−1. The percent Cr sorption varied from 70.05 to 88.75% in first cycle and showed decreasing trend in the subsequent cycles. The elutant 0.5 M H2SO4 desorbed 89.56% of chromium furthermore eluted chromium was utilized for leather tanning. Reusing of recovered chromium for tanning experiments does not alter the leather Tensile (240.82 kg cm−2) and tear strengths (32.41 kg mm−1). This study suggested that recovered chromium from biosorbent can be well utilized for leather tanning to attain the leather of equivalent qualities as that of conventional methods which could save 20–22% of the production cost besides defending the environment from Cr contamination. [ABSTRACT FROM AUTHOR]

Cross-linking, also called tanning, improves mechanical properties of leather and also increases its enzymatic and thermal stability. As a final product, leather has an ultimate tensile strength (σ) of 8–25 MPa and an elongation at break (ε) of >30 %. Mycelium-based materials are a sustainable alternative to leather. Here, the effect of cross-linkers was assessed on mechanical properties of Schizophyllum commune mycelium sheets. To this end, glutaraldehyde and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) were used as well as extracts of Ligustrum vulgare leaves, and bark of Acacia mearnsii and Caesalpinia spinosa. Untanned sheets had a σ of 7.8 MPa and an ε of 15.2 %, while the best overall combination of strength and elasticity was obtained with 0.1 % glutaraldehyde with a σ of 11.1 MPa and an ε of 14.6 %. Cross-linking also increased enzymatic stability and reduced mycelial water absorption but did not result in increased thermal stability. Fourier transform infrared spectroscopy (FTIR), 1D nuclear magnetic resonance spectroscopy (NMR), and amino acid analysis showed that glutaraldehyde bound both protein amino groups and polysaccharide hydroxyl groups by forming Schiff bases and acetals, respectively. Together, synthetic and vegetable cross-linkers can be used to obtain mycelium materials with leather-like tensile strength.

Leather tanning can be done by soaking the skin in pits or rotating in tannery drums. Technical soaking of rotate movement and static soaking affects the skin microstructure matrix. This study aims to compare the quality of wet blue leather tanned by static soaking in a vessel and rotating in a tannery drum, particularly in terms of chrome uptake and thermal stability. The penetration time in the soaking experiment varied from 8, 16, 24, 32, 40, 48, and 56 hours. Meanwhile, the control was processed in a small-scale tannery drum with two hours of penetration time. Then, each sample was subjected to basification using HCOONa and NaHCO3. The results showed that all samples increased in weight and thickness after tanning. After penetration, wet blue leather tanned in a tannery drum performed better blue-green colour evenness compared with the soaked ones. Tannery drum leather also showed better chromium uptake, shrinkage temperature, and thermal stability. When the drum rotates, the pickled pelt gets mechanical action, such as being stretched, bent, and slammed, helping the collagen fibre open and the chromium penetrates deeper and faster. This study revealed that darker wet blue leather indicates higher thermal stability and chromium uptake.

Illegal wildlife trade is currently on the rise, and it is becoming one of the most lucrative crime sectors. The rarer the species, the higher the demand. Wildlife trade falls under international regulations, such as the CITES convention. Proving that this convention has been violated is a complex process and can be very difficult to do. DNA analysis methods remain (in many cases) the only way to determine whether a certain specimen originated from a protected animal species, a specific individual, or a species in which it is legal to trade. Tanned animal hides are a specific type of specimen. With this type of biological material, obtaining amplifiable DNA is often difficult. This pilot study aimed to map the effect of the chemicals used in the tanning process on the degradation of the DNA yielded from such samples. The DNA was quantified using two different approaches: qPCR and Qubit fluorometry. The degree of DNA fragmentation was assessed by determining the degradation index. The results indicate that reagents containing chromium have the greatest influence on DNA degradation. However, by using the presented protocol, enough amplifiable DNA can be obtained from hides treated with aluminum-based reagents. [ABSTRACT FROM AUTHOR]

This study was conducted to examine the adsorption of Cr (VI) metal using Spirulina sp (inactive) biomass and its application in leather tannery wastewater. The treatment was carried out to determine the influence of independent variables on Cr (VI) adsorption with variations in pH, contact time, and metal solution concentration. The values of the solution pH, adsorption time, and concentration of the best metal solution were used to determine the center points of the optimization variables through Response Surface Methodology (RSM). The results showed that based on the FTIR test, macromolecules present in Spirulina sp biomass included amino, carboxylate, and hydroxy groups. The combination of factor variables that produced the optimum response was at pH 3.165, contact time of 66.58 minutes, and Cr (VI) metal ion solution concentration of 22.9 mg/L, resulting in a Cr (VI) adsorption efficiency of 69.66%. The adsorption pattern was included in the Freundlich adsorption isotherm, and the application of Spirulina sp biomass adsorbent to tannery waste reduced the concentration of Cr (VI) from 3.9 g/L to an undetectable level at

Abstract Herewith waste collagen was processed using a deep eutectic solvent (DES) obtained by the complexation between choline chloride (ChCl) and ethylene glycol 1:2 (ChCl:2EG) to form a material with properties similar to leather. The material generated using the waste tanned collagen processed with ChCl:2EG followed by mechanical extrusion was found to show characteristics similar to the one obtained from the material using animal hide powder. However, the tensile strength of extruded collagen was substantially higher (7.56 MPa vs. 0.23 MPa). The improved strength and structure may be due in part to traces of iron imparted into the material during extrusion of the acidic collagen sample. Nevertheless, the material thus generated was found to have a lower degree of crystallinity compared to commercial leather samples. Overall, the process demonstrates a facile method preparing a useful material out of waste collagen by the intervention of DESs. Graphical Abstract

Acacia xanthophloea is a tree in the Fabaceae family with wide distribution mainly around Laikipia in Central Kenya and major parts of the Rift Valley town of Naivasha, Kenya. A number of trees under the Fabaceae family are renowned as sources of vegetable tannins for leather processing. Despite recent advances in research, locally available vegetable tanning materials have not been widely exploited in Kenya for commercial tanning purposes. This study aimed to evaluate the mechanical properties of goat leather tanned with crude extracts of Acacia xanthophloea from Naivasha, Kenya. Crude extracts of Acacia xanthophloea combined with pre-tanning and tanning procedures were used to produce leather. The commercial mimosa was used as a control. The leather tanned with crude extracts of Acacia xanthophloea had a thickness of 0.81 ± 0.11 mm, tearing strength of 37.87 ± 2.09 N, tensile strength of 27.50 ± 7.51 N/mm2, percentage elongation of 18.00 ± 6.67, grain crack of 6.19 ± 0.20 mm and grain burst of 7.10 ± 0.27 mm. The crude extracts of Acacia xanthophloea confer good tanning and give the leather a reddish tinge, whereas some mechanical properties attenuated, compare favourably with the control (mimosa). Acacia xanthophloea which is abundantly available in Kenya with scarce use can potentially be cultivated and refined as a commercial source of tannins.

Insect cuticle is an apical extracellular matrix produced by the epidermis, tracheal, hind‐ and foregut epithelia during embryogenesis and renewed during molting and metamorphosis. However, the underlying regulatory mechanism for embryonic cuticle formation remains largely unclear. Here, we investigate the function of the transcription factor POUM2 in the embryonic cuticular formation in Bombyx mori, a model lepidopteran insect. Clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR‐associated protein‐9‐mediated knockout of POUM2 resulted in the defect of cuticular deposition, pigmentation, and sclerotization in the embryos. Differentially expressed transcripts analysis of 7‐d‐old embryos identified 174 up‐ or downregulated cuticular protein transcripts, 8 upregulated chitin degradation transcripts, 2 downregulated chitin synthesis transcripts and 48 up‐ or downregulated transcription factor transcripts in the POUM2−/− embryos. The expression levels of the key factors of the tyrosine metabolic pathway, such as tyrosine hydroxylase (Th), Dopa decarboxylase (DDC), and arylalkylamine N‐acetyltransferase (aaNAT), were significantly decreased in the POUM2−/− embryos. POUM2 isoform POUM2‐L specifically bound the POU cis‐regulatory element (CRE) in the Th promoter and increased the transcription of Th, whereas POUM2‐S could not bind the POU CRE, although it also increased the transcription of Th. Heterogeneous nuclear ribonucleoprotein Squid‐1 directly bound the POUM2 pre‐mRNA (messenger RNA) and inhibited the alternative splicing of POUM2‐L to POUM2‐S mRNA. These results suggest that POUM2 participates in the cuticular formation by regulating the chitin and cuticular protein synthesis and metabolism, and the cuticular pigmentation and sclerotization by regulating tyrosine metabolism during embryogenesis. This study provides new insights into novel function of POUM2 in embryogenesis. [ABSTRACT FROM AUTHOR]

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Wastewater production is a major environmental issue for the leather and textile industries: in a modern plant, several synthetic dyes are used in separated coloring batches whose wastewaters are usually mixed, diluted with other process water streams, and sent to a unique wastewater treatment plant. This includes specific physical and biochemical tertiary treatments to remove dyes efficiently. One of the main difficulties of these processes is the presence of multiple dyes, which cannot be treated with the same efficiency as a "wide-spectrum" process. This work explores the possibility of using conventional granular activated carbon (GAC) and a new polyurethane foam (PUF) for the adsorption of an acid red dye in the wastewater of a specific coloring batch of the tanning industry. The aim of this work is twofold: on the one hand, we aim to explore the performance of the new PUF sorbent; on the other hand, we aim to explore the possibility of using adsorption as an optimized pre-treatment for single-dye batches, which may take advantage of the presence of a single type of target dye and its higher concentration. The effluent is then sent to the wastewater treatment plant for further depuration. [ABSTRACT FROM AUTHOR]

Extensive use of water in different industries particularly leather tanning has drawn attention in recent years. In this research, a new approach has been developed to reduce water consumption in the tanning industry. Four different experiments were carried out on raw goat skins by using various quantities of water which were much lower than the influx of water consumed in the conventional leather tanning processes. One control experiment was conducted in which the volume of water was used as 100% of the conventional method (37 m3/ton) in every step of leather processing. The experiments showed a reduction of 15%, 25%, 35%, and 50% in water consumption respectively from the control method used in the processing of raw leathers. The resulting goat leathers were examined with various physical tests such as tensile strength, percentage of elongation, stitch, tongue tear strengths etc. The results showed the presence of all significant qualities. The processed leathers were thermally stable and exhibited percentages of elongations in the range of 40.94% to 50.85% which were considerably higher than those (38.1%) observed with the conventional method. Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA), and Fourier transform infrared (FT-IR) studies confirmed identical morphological and structural characteristics of all processed leathers. These methods of leather processing are environmentally friendly and suitable for large-scale industrial production. Efficient reduction of water use in raw leather processing may significantly decrease the toxic liquid waste and tannery pollution.

Micro-fined leather buffing dust is an airborne pollutant. In this study, clay was mixed with leather buffing dust fly ash (LBDFA) in various proportions (0 %, 4 %, 8 %, 12 %, 16 %, and 20 %), fabricated brick, dried, and burned in the brickfield at 1000 °C. Results suggested that 12 % LBDFA incorporated brick exhibited weight loss on ignition (5.65 %), area shrinkage (3.96 %), water absorption (15.63 %), compressive strength (16.74 N/mm2), and efflorescence (nil). SEM micrographs depicted composite's micro-fibrous structure creating lightweight brick. The NEN 7345 leaching showed leached metals within standard range. LBDFA in brick production is an alternative option for managing solid waste in tannery.

Writing a book on a primitive technology in today’s fast-paced society, fueled by the internet and instant gratification by observing a skill through video, is a risky endeavor. Adding to this risk is the fact that there are many books about brain tanning already on the market. Two of these are classics of the two most common methods; Jim Riggs, “Blue Mountain Buckskin” (dry –scrape method) and Matt Richards, “Deerskins into Buckskins” (wet- scrape method), which are regarded by most as recommended reading for a hide tanning course. Despite these risks, Markus Klek rose to the challenge and wrote an excellent book about leather tanning.