Leather Processing Research Articles

Utilization of Limed Flesh Through Fat Extraction and Soap Preparation

Leather industry is an export oriented industry in Bangladesh and according to the Export Promotion Bureau, in the fiscal year 2017–2018 leather sector earned US$1.03 billion by exporting leather, leather products, and footwear [1] . But it is a matter of great concern that this industry produces lots of pollution which impacts on our environment immensely. Normally thousands of kg raw cattle hide converts into 200kg finished leather [2]. Leather processing (tanning) is a complex procedure comprising of several technological steps to shield the raw hide/skin against microbiological degradation as well as to stabilize collagen with defined tanning agents which produce a significant amount of waste. Wastes originate from all stages of leather manufacturing, such as tiny particles, residues from various tanning stages and reagents from different waste liquors comprising of cuttings of raw hides and skins , trimmings and shavings, fleshing residues, solid hair debris [3]. In this conversion process the amount of total solid waste produces is about 450-550kg. This work is intended to develop a fat extraction method from the limed flashings for soap production. In leather processing, just after washing, following the liming process, swollen pelts (lime treated hide/skin) have to pass through an operation to remove the remaining fat and flesh from the flesh side in order to improve the diffusion of chemicals into pelt is known as fleshing. Generally, fleshings are kept indiscriminately nearly the industrial area as green, which has an adverse effect on the environment including human health. It contains a considerable amount of fat, which could be great source raw materials for soap. The process could be optimized for large scale production, which would be allowed to produce a new product for the commercial use. The approach could also contribute a significant reduction in the environmental impact of inevitable solid waste and decrease the costs associated with disposal.

ROMAN ARMY AND SALT EXPLOITATION IN DACIA

The authors study the connections between salt resources, salt exploitation and Roman army in Dacia. Even though salt resources are attested almost across the entire province of Dacia (excepting perhaps the western part), the eastern part is the richest not only in salt deposits, but also salt springs. Salt was important not only for the troops (food — nutrition and preservation, hide and leather processing, horses’ and other animals’ alimentation), but also for the civilian population. The army needed salt not only for its own purposes, but for distributing it in the rest of the province. However, despite the important role of the army concerning the salt resources’ protection, we have to pay attention also at he other missions the troops were charged with.

OSTRICH BREEDING IN CHINA

Ostrich (Struthio camelus) has become one of the valuable agricultural enterprises in many countries of the world. China has become Asian's number one ostrich species raiser with about 20,000 ostrich bred farms. China started in 1992 to import some ostrich species from South Africa. Ostrich was raised globely since the 1980s for its feathers, meat, egg, hair and bone are all of high economic value. China's progress in producing ostriches has improved it's rank from fifth to the second globely in recent years, due to the following factors: The area of pastures which reached 40% of the area of ​​China.Large amounts of agricultural wasts. China has been producing iron and thus has produced the cheapest agricultural machines, such as irrigation machines, cutting and pressing the feed. China achieved progress in the electronical industries which have enabled it to produce hatchery machines to promote the poultry industry .China is making use of solar energy and producing cheap energy used to irrigate agricultural land and operate farm machinery. Thus, the price of feed is cheap and therefore it costs to feed the ostriches as little as possible.Use of seawater desalination technology and cultivation of saline-tolerant fodder crops such as fodder beat, bonicam and blubank .The use of leather processing tectology and production of the finest leather industries of shoes and bags .China has imported large amounts of ostriches from South Africa and used the best breeding and ostrich production systems in South Africa. The most important factors leading to the success of the ostrich industry in china are limited into three factors. First: Nutrition and cheap feed should be provided by planting enough alfalfa. Using solar energy to irrigate these lands. Sowing saline and drought tolerant genotypes, such as blubanks and bonecam, as well as machines for cutting and making pellet for green feed. Second: Hatching Third: Health.

Benefits and challenges of pastoralism system in Ethiopia

Pastoralism is an important livelihood system practice in most of the dryland areas of the globe.It is a source of income and way of livelihood for hundreds of millions of world population.This research aimed at explaining the benefits of pastoral system, identifying the main challenges the sector faced based on secondary data obtained from different official records such as FAO, CSA (Central Statistical Authority of Ethiopia) and published research article and government reports. Besides this, this research also tried to indicate the possible way outs. Economically it contributes about 10%-40% of national GDP of countries and over 1.3 billion people benefited from the livestock value chain. Ethiopia has the largest livestock population in Africa (first in Africa, and 5th in the world) and 20 % of the national export and 90% of live animal export of the Ethiopian trade, and 80% of annual milk supply to the Ethiopian community resulted directly from the pastoralists. Yet the sectorial contribution has many bottlenecks and the most important one is lack of appropriate policy due to the misconception that the system is economically not feasible and environmentally unfriendly. In addition to this, unexpected, but short period drought and weak market chain, limited access to feed, equipment and information, market chain, animal health (veterinary) are contributing factors to the low contribution of the livestock sector. Ethiopia, with its huge livestock population and the increasing demand of global meat and milk demand, should give attention towards the sectorial development including provision of infrastructure such as milk and milk processing industries, leather and leather processing industries, and focus on Diversification of economic activities inthe pastoral areas. Besides, the government of Ethiopia should give an emphasis on developing policies and strategies to increase productivity of livestock and maintain the development of the sector. Furthermore, the government should devise mechanisms to control the illegal inter-boarder live animal export and way of measuring unaccounted (nonmarketable) values of livestock pastoral contributions.

Recent use of selected phytochemistry to mitigate environmental challenges facing leather tanning industry: a review

Leather tanning technology impacts negatively on the environment as a result of chemicals in the tannery effluents that increases the concentrations of chemical oxygen demand, Biological oxygen demand, total dissolved solids, total Kjeldahl Nitrogen and formation of Cr(VI) among others in the environment. This has led to the profiling of the industry by legislative bodies as a major source of pollution and hence urgent cleaner and eco-friendly innovative technologies are required that will mitigate the environmental pollution. Many studies have recommended green chemistry tanning protocols and systems involving plants since are non-carcinogenic, non-toxic, biodegradable, agro-renewable, sustainable and economical. Numerous studies have evaluated the potential of phytochemistry in leather tanning processes. However, these studies only focused on individual processes or individual plant phytochemicals. Hence this review compiles the selected plants, their phytochemical screening results, their applications in tanning process and their potential for leather tanning. The review has shown enormous capacity of plants and their phytochemicals that can replace synthetic inorganic materials in leather processing and guarantee quality. Plants have a greater applicability in this industry since they have multiple beneficial actions during processing and the final processed leather. Some plants can be used at all tanning processes due to wide variety of important phytochemicals and the final leather is more superior quality to the conventionally processed leather. Other studies have alluded to the possibility of some plant products that have the potential in the industry but yet to be utilized. Further studies have been recommended.

Wastewater from leather tanning and processing in Palestine: Characterization and management aspects

Leather manufacturing industry has major environmental impacts. Characterization of tannery's wastewater (WW) is a key step in the management of wastewater released from various processes. This study presents some physicochemical characteristics measured in wastewater. It compares the pollution loads released from both goat and cow hides processing. The main pollution characteristics of wastewater released from two local tanneries were determined experimentally, through analyzing real samples of industrial discharges. These include chemical oxygen demand (COD), total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), pH, and the concentrations of chloride, ammonia (NH3) and chromium in both states, Cr (III) and Cr (VI). Characterization of such processes effluents assists in identifying waste generation rates and discharges, and then in recommending cleaner production options. The results shows that the amount of WW produced in the local Palestinian tanneries is much lower than tanneries worldwide, whereas it is more concentrated with pollutants. Liming process has the highest COD and the highest pH value, where tanning process releases WW highly concentrated with chromium. Real process measurements and mass balance calculations indicated that the chromium uptake efficiency is only 46.6%. Such a low efficiency indicates that cleaner production measures are essential in local tanneries.

Extraction of elastin from tannery wastes: A cleaner technology for tannery waste management

Abstract During leather processing, most of the trimmed raw skins/hides are thrown as wastes which require solid waste management. In the present study, raw hide trimming wastes have been used as the source for extracting elastin. Elastin is extracted from raw trimming wastes through thermo-chemical treatment method using alkali pre-treatments. The physical characterization using differential scanning calorimetry showed the melting point at 104 °C. Elastin has shown higher denaturation temperature above 275 °C and thermal gravimetric shows six mass loss steps. Through thermo-chemical extraction method, 90% of yield has obtained. From various characterization results, it is observed that extracted elastin is chemically confined with its physicochemical properties. Moreover, biocompatibility studies also confirm that the enhancement of cell proliferations in the presence of elastin, which makes it more non-toxic and biocompatible which makes it feasible for tissue engineering applications. The study provides an insight into tapping unused high-value products from tannery wastes.

Improved chlorine and chromium ion removal from leather processing wastewater by biocharcoal-based capacitive deionization

Red oak biocharcoal, a novel electrode material that is inexpensive and highly conductive, was used for capacitive deionization (CDI) to simultaneously remove Cl− and Cr3+ from leather processing wastewater. The results showed that both the carbonization temperature and time played important roles in reducing the resistivity (ρ) of biocharcoal. Additionally, at 1000 °C and 3 h, the ρ value was reduced from 4.68 to 1.19 Ω·cm after the addition of Fe2O3. KOH impregnation enhanced the desalination capacity of the biocharcoal electrodes by increasing the specific surface area and hydrophilicity. Under the optimal operating parameters (voltage of 1.8 V, flow rate of 10 ml/min and electrode spacing of 2 mm), the KOBC15 electrode exhibited a maximum adsorption capacity of 13.79 mg/g. After 10 cycles of CDI system operation, the removal rates of Cl− and Cr3+ reached 86.7% and 100%, respectively, in simulated leather processing wastewater. Thiswork provides new ideas and methods for the treatment of high-salinity wastewater.

Enhanced production of alkaline protease by Neocosmospora sp. N1 using custard apple seed powder as inducer and its application for stain removal and dehairing

Alkaline proteases find extensive applications ranging from detergent industries to therapeutics due to their broad alkaline range activity. The present work describes the first report on optimization of alkaline protease production from Neocosmospora sp. N1 and explores its utility in detergent and leather industries. Wheat bran was found to be a suitable substrate for protease production under solid state fermentation amongst several low cost agro-based materials used in this study. Protease production was enhanced when wheat bran was supplemented with a novel inducer, custard apple seed powder in the ratio of 4:1 which increased enzyme production up to 1.88 fold. One factor at a time approach was used to select parameters important for production and response surface methodology was used for further optimization. The optimum level was attained at 123 h fermentation time, 63% moisture content, 1 × 10 8 spores/ml inoculum size and 1.4 mm particle size which resulted in 3.12 fold increase in protease production. The partially purified enzyme exhibited maximum activity at 60 °C and was active over a wide pH range of 8–12. Protease was compatible with various laundry detergents viz . Tide, Surf Excel, Ariel, Wheel etc. showing more than 80% stability even after 3 h of incubation and was efficient in removing blood stain from the cotton cloth. The enzyme was also more efficient in dehairing goat skin as compared to conventional leather processing treatment. • Statistical optimization of alkaline protease production in SSF from Neocosmospora species is studied. • The protease production increased 1.88 fold by use of custard apple seed powder as a novel inducer. • 3.12 fold enhancement in protease production was achieved by using Box-Behnken Design. • Neocosmospora sp. alkaline protease is efficient in removing blood stains having 80% compatibility with commercial detergents. • Protease produced cleaner, whiter, smoother skin as compared to sulphide treatment.

Collagen structure changes during chrome tanning in propylene carbonate

Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry.Graphical abstract

Adsorption of Cr(VI) from aqueous solution by crosslinked cationic konjac glucomannan with different degree of substitution

Chromium has numerous industrial applications, such as metallurgy, processing of leather, producing chromic acid, acting as catalyst and electroplating. These activities cause Cr(VI) contamination in air, soil and water resources. Developing efficient and cost-effective adsorbents for removing Cr(VI) is of utmost importance. Crosslinked cationic konjac glucomannan (CCKGM) with different degrees of substitution (DS) 0.226, 0.391 and 0.456, were prepared by reaction of 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride, konjac glucomannan (KGM) and epichlorohydrin and used to adsorb Cr(VI) ions from the aqueous solutions. Then the adsorption behaviour of CCKGM to Cr (VI) was explored. The adsorption effect of CCKGM on Cr(VI) is affected by pH, Cr(VI) initial concentration, adsorbent dose and temperature. With the increase of DS, adsorption capacity increased. The adsorption capacity was 31.52 mg/g, 58.82 mg/g and 62.59 mg/g corresponding to DS 0.226, 0.391 and 0.456, respectively. Adsorption can get equilibrium within several minutes and follows Langmuir isothermal adsorption. The process is exothermal and low temperature is favourable for adsorption. CCKGM has potential to be used as adsorbents for Cr (VI).

Clay/polymer nanocomposites as filler materials for leather

Abstract In the present study organoclay based acrylic polymer nanocomposites were prepared via emulsion polymerization and used as filling agent for leather. The main objective of the study is to use inexpensive clay for preparation of synthetic tanning agent (syntan) for leather processing. Prepared clay/polymer nanocomposites consisting of different weight ratios of organoclay were characterized for morphological and mechanical strength properties. The results showed that surface roughness and mechanical strength of the films increased with increasing concentration of organoclay. The particle size and zeta potential analysis reveal that the clay/polymer nanocomposites (CPNs) were electrostatically stable with particle size varying between 62 and 295 nm. The leathers treated with experimental clay-polymer nanocomposite incorporated with 5 wt% clay exhibited smooth fibrillar arrangement suggesting excellent dispersion and filling properties, thus opening new avenues for efficient leather processing. The experimental leathers also exhibited better tensile strength of 28 ± 0.5 compared to control 26 ± 0.5 N/mm2 and organoleptic properties such as fullness, belly filling and softness were also improved. Thus, the preparation and application of the syntan paves a way to the sustainable approach for making leather filling agent, which is cost-effective, abundantly available and eco-friendly.

Protease immobilized nanoparticles: a cleaner and sustainable approach to dehairing of skin

Leather industry has been undergoing a paradigm shift from chemical to enzyme-based processes for removal of hair and opening up of fibers from skin prior to its conversion into leather. This involves the use of protease for hair removal and amylase for opening the fibers in the place of sodium sulfide and calcium hydroxide, respectively. The enzymes are currently applied through various methods such as the use of salt, kaolin, and sawdust. Additionally, the robustness of the enzymatic approach under various environmental conditions needs to be ensured to enhance its popularity. With a view to this, the possibility of utilizing enzyme immobilized on zinc oxide nanoparticles was explored. Enzyme immobilized nanoparticles (nano-biocatalyst) at a concentration of 1.0% was optimized for hair removal, and compared to conventional sodium sulfide method. The decrease in the time required for matching efficiencies has been observed with the use of nano-biocatalyst. Histopathology results confirmed that there is no distortion of fibers with the usage of nano-biocatalyst. The study demonstrates the potential use of enzyme immobilized nanoparticles in leather processing and could ideally turn out to be a sustainable approach on account of reduction in emission loads from the process.

Performance and Isotherm Studies in Phenol Adsorption From Wastewater Using Low Cost Biomass Derived From Coconut Shells

With the growth of urbanization and industrialization, water bodies are getting polluted. Among various pollutants, phenol-based pollutants are common water pollutions which originate from wastewater discharged from processing manufacturing industries like petrochemical refineries, ceramic plants, textile processing, leather processing, synthetic rubbers, etc. These pollutants are toxic and have long-term ill effects on both humans and aquatic animals. Adsorption is well proven technique which is widely used for removal of pollutions from aqueous environments. But this process, is hindered due to the cost of adsorbents especially for large scale continuous processes. In this regard, adsorbents derived from waste biomass can be a great asset to reduce the cost of wastewater treatment. To meet this objective, coconut shells are chosen as biomass which is abundantly available from south east Asia. This biomass is converted into activated carbon and hence used to remove phenol from wastewater. Batch adsorption experiments were performed with different initial concentration, carbon dosage, pH and contact time. At a lower concentration of 50 mg/L of initial feed (phenol) concentration resulted in around 90% phenol removal and henceforth optimum results in phenol removal obtained in only 64%. Experimental results are in good agreement with Langmuir adsorption isotherm model and have shown a better fitting to the experimental data. These studies confirm that the coconut shell-based activated carbon could be used to effectively adsorb phenol from aqueous solutions.

Phytoplankton Cultures for Tannin Biodegradation

Tannins are special plant metabolites used in leather processing that act as pollutants. These substances are toxic to aquatic biota and can cause cell rupture. These harmful effects make the treatment of tannery wastewater difficult. Phytoplankton species are community components that are rarely considered in the biodegradation of organic compounds. However, in association with bacteria, these organisms can improve the biodegradation of pollutants by different mechanisms. The aim of the present study was to evaluate the potential of non-axenic cultures of Chlorella vulgaris containing Lactobacillus casei and Synechococcus sp. containing Rhizobium rosettiformans and Sphingomonas koreensis to biodegrade tannic acid (TA). Cultures in BG-11 medium containing TA (250 mg L−1) were incubated under a photoperiod or in the dark and monitored for 96 h. The cultures with added TA grew more than the control cultures under both the photoperiod and dark conditions. A reduction in the TA concentration and the TA metabolite gallic acid was observed under both conditions. Ellagic acid was identified and demonstrated resistance to biodegradation under the evaluated conditions, and neither of the other metabolites was detected. BG-11 culture medium is poor in organic material; therefore, microalgae and cyanobacteria contribute to bacterial metabolism. Under experimental conditions, phytoplankton species seem to contribute to the biodegradation of tannin residues, and in natural environments, they may aid in the bioremediation of sites contaminated by these pollutants.

Red‐Emitting Ratiometric Fluorescence Chemodosimeter for the Discriminative Detection of Aromatic and Aliphatic Amines

AbstractA NIR‐emitting fluorescent probe using phenothiazine and 1,3‐dimethylbarbituric acid (PMB) connected through methylene bridge was developed in a two‐step simple chemical reaction. The fluorescent probes were highly reactive towards various primary amines and the reaction was accompanied by the changes in the optical and fluorescent properties of the PMB characteristic to the amine and thereby can have the potential to be used as a sensor for amines. In addition to the ratiometric changes in the fluorescence intensity corresponding to the PMB before and after reaction with an amine, the emission spectral maximum is specific to the analyte. For, example 1,4‐diaminobenzene, 4‐methoxyaniline, aniline, hydrazine, ethylamine, ethylenediamine respectively shows the maximum at 532, 546, 555, 484, 497, and 488 nm and this unique feature originated due to the involvement of the analyte in the extended π‐conjugation with the probe. Sensor strips prepared using PMB coated filter paper were able to sense the volatile amine gases with shorter response time. Analysis of the strips using the CIELAB 1976 color coordinates provides different signals for hydrazine, aniline, propylamine, and ethylamine gases. The applicability of the sensor was further ascertained by monitoring the decomposition of skin used for leather processing and also proteins engineered with an amino‐functionalized unnatural amino acid.

Hydrothermal carbonization of waste from leather processing and feasibility of produced hydrochar as an alternative solid fuel

This study presents hydrothermal carbonization (HTC) of leather waste (LW) to produce hydrochar and feasibility of using produced hydrochar as solid fuel. The results showed that a relatively low HTC treatment temperature (180–200 °C) improved both the hydrochar product yield (>82.9% by dry weight) and its potential use as a solid fuel with in terms of its physicochemical properties and heating value. Furthermore, the hydrochar showed a higher heating value (5807–6508 kcal kg−1) compared to that of low-ranked coals (i.e., sub-bituminous and lignite), and stable combustion characteristics at a higher temperature. This allows the hydrochar to be considered as a suitable alternative to conventional fossil fuel. In addition, the decrease of nitrogen content in the hydrochar during the HTC treatment, and the inherent low sulfur content of LW could make hydrochar a more appealing clean energy source. The findings of this study suggest that the conversion of LW through HTC can be a useful method for waste management and energy recovery from abandoned biomass.

Fashion Product Development Process with Reference to Women's Participation

The process of the development of new fashion clothing requires all actors in the process to invest tremendous effort in order for the right model to reach its customer at the right time and in the right place. Although the textile and leather processing industry in Serbia employs large number of people, little attention has been paid to fashion marketing, thus it is the subject of this paper as regards the process of the development of fashion products with reference to participation of women in this process, with the aim of presenting characteristics and specificities of the said, along with the results of the secondary research in relation to the subject mentioned.

Improving training on cleaner production through Borich needs assessment model in SAF leather industry, Nowapara, Jessore, Bangladesh

The present study has been undertaken to assess the training needs of employer on cleaner production in SAF leather industry at Jashore district in Bangladesh. Using Borich Need Assessment Model for training needs. A total 60 employers were surveyed including 20 employers from each group and data were collected on socioeconomic condition of responders, management activities in leather processing and environment pollution related issues through the questionnaire. The importance level, competence needs were analyzed and ranked using weighted discrepancy scores (WDS). The study revealed that the highest WDS score (15.38) was found for Beam house worker that indicated the training is strongly needed for them on identification of harmful chemicals and environmental pollution. Crust and fishing unit worker needed high training (WDS score= 15.10) on understanding the types and quantities wastewater discharged from industry during leather processing and its management. The WDS score 14.78 was estimated for administrative employers where they needed high training on controlling odor problem from the industry. Although they have an average knowledge about the environmental pollution, they did not have qualified level of capabilities on understanding how to use some environmental tools e.g. social impact assessment and environmental auditing. Therefore, majority of the respondents preferred training for reduction of environmental pollution.
 Asian Australas. J. Food Saf. Secur. 2019, 3(1), 15-22

Greener Approach for Leather Tanning Using Less Chrome with Plant Tannins and Tannins Mediated Nanoparticles

Making out animal skins or hides to leather is commonly called as tanning. This research was done for utilizing tannins of some medicinal plants and tannin induced green-synthesized silver nanoparticles along with minimal concentration of chromium to enhance the physical and mechanical properties of leather and thereby reducing the pollution caused by chromium in effluent which crucially affect the soil fertility, ground and surface water. In this study, Cassia alata, Euphorbia hirta, Thespesia populnea and Wrightia tinctoria were collected and tannins were extracted from the leaves. Tannins were utilized for production of silver nanoparticles. The extracted tannins and tannin induced silver nanoparticles were characterized, where the silver nanoparticles were found to be crystalline. Further, the tannin and tannin induced silver nanoparticles were used in leather processing either alone or in combination with chromium. The quality of tannin/silver nanoparticle treated leather was compared with chemically tanned leather for its tensile strength, tear strength, shrinking temperature, etc.