Leather is made from animal hides and skins that have passed through several stages of processing, from soaking to finishing. Unhairing is a crucial processing stage in which hair is removed from the animal hide or skin through open up the hair and it facilitates subsequent operations. The conventional sodium sulfide-based unhairing process generates a high volume of effluent, which accounts for 50 to 70% of the total biochemical oxygen demand (BOD) and chemical oxygen demand (COD) load in the tanneries’ effluent. This study aimed to investigate the potential of unhairing agents prepared from locally available plants. The research employed qualitative methods. Plant materials are collected, dried, and ground. In different proportions, unhairing extracts were obtained from Phytolacca dodecandra leaves, Cucurbita foetidissima fruits, and Solanum incanum fruits. In the conventional soaking process, plant extracts were applied in various concentrations to sheepskin. The physical parameters of conventionally processed (control) and experimentally treated leather were examined using FTIR, SEM, tear strength, percentage of elongation, and organoleptic tests. The unhairing solution was prepared from a mixture of 0.5% S. incanum extract, 0.5% P. dodecandra extract, 0.6% C. foetidissima extract, and 260 g/L lime powder lime, and this solution effectively removed the hair from the sheepskin in both hairs saving and hair burning unhairing process. The study revealed that the sheepskin treated with the plant extracts based on an unhairing agent and the conventional unhairing agent showed a comparable tensile strength (42.3 kg/cm and 45.2 kg/cm), tear strength (140.1 kg/cm2 and 143.5 kg/cm2), and percent elongation at break (40.2 and 42.3), respectively, which were above the permissible limit for leather production making. According to the study findings, the plant extracts have a good potential for removing hair from sheepskin, and they are eco-friendly and cost-effective compared to unhairing chemicals such as sodium sulfide.

Industrial effluents have a serious problem on our ecosystem. Tannery effluent contains a huge amount of pollutant compounds such as toxic substances which need to be treated using either synthetic or natural products. The present study focussed on the treatment of tannery effluents using water hyacinth plant leaf extract. Though some researchers have tried to use this extract for the same, the researchers have experimented only to treat that of Cr3+ and there are a bit of difference in the methodology they followed. In addition, the scope of this research was wider. In this study, fresh raw WH leaves were collected from around Lake Tana, Ethiopia, cleaned and made to powder and then extraction was performed using different solvents. The solvent effects were examined using the ANOVA test. The tannery wastewater was treated with the extracts and parts of the effluents were kept as a control for comparison. Treated and untreated tannery effluents were compared using standard methods such as SLC 22, SLC 8, APHA 2540C, APHA 2540D, and Hack LCK 139 to determine Cr6+, Cr3+, TDS, TSS, and TKN, respectively. The highest amount of Cr6+, Cr3+, and TKN were removed at 30% water hyacinth leaves extracted by distilled water solvent and that of the least was found at hyacinth leaves extract by ethanol solvent but by acetone in BOD and COD treatment. In addition, though it was out of the permissible limit, by using the same amount of the material extracted by distilled water solvent some amounts of BOD and TDS were removed from the wastes compared to that of untreated tannery effluents. Generally, water hyacinth leaf extract is found effective material for the treatment of tannery effluents and can be used in the sector industries. Future studies may be required for setting the most optimum extract concentration for better results.

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Curing is the first process of skin treatment mainly using sodium chloride salt to prevent its decay. At soaking step of tannery, the effluents will be discharged to the environment, which contains the chloride ion, which will negatively affect our environment. Therefore, it should be either treated or reused so that it can help to reduce amount of chloride ion of the soaking effluent discharged to the environment and cost of pickling. This study focused on recycling of curing salt for sheepskin pickling and studying its effect on the pickled skin’s properties. Salt was recycled from cured skins manually, and it was purified through dilution, filtration, treatment, and drying. Five enzymatic bated sheepskins were collected from Bahir Dar, Ethiopia. The recipes were developed based on the weight of the pelt which was going to be pickled with 0.8% H2SO4, 0.5% formic acid, and 80% H2O for each trial and the recycled salt at different concentrations (8%, 8.5%, 6.5%, 7%, and 7.5%) for S1, S2, S3, S4, and S5, respectively. Bromocresol green was the pH indicator. Then, properties of treated samples were measured and evaluated in line with ISO standards, and the pH of the recipe was checked. The results showed that S1 treated with the mentioned materials and 8% salt amount has highest tensile strength (80.3 N/mm2). In addition, S1 has also the maximum tear strength of 60 N/mm2 and the minimum was 45.69 N/mm2. On the contrary, S3 has shown the least values of tensile strength and elongations as well as least tear strength. S1 has the maximum shrinkage temprature of 107°C and S3 has that of the least value 89°C which is lower compared with the standard shrinkage temperature, 95°C. The pH values were found to be within the standard for pickling. The overall result of this study was promising.

Natural fibers have the potential to replace synthetic fibers for making polymer composites due to their remarkable properties. Polyester is one of the core materiel used for textile and leather due to hydrophobic property. Sisal fibers have high strength among various naturals and can be used as the supporting material for polymers. A detailed experimental study was conducted for the extraction of sisal fiber and composite development. The fibers were treated by using 2%, 6%, and 10% NaOH concentrations within 24, 48, and 72 h soaking time. Composite was made from different sisal to polyester ratios of 20 : 80, 30 : 70, and 40 : 60 (w/w). Mechanical properties such as tensile strength and flexural strength of treated, untreated, and reinforced fibers were determined. Functional groups of both the treated and untreated sisal fibers were characterized using Fourier transform infrared spectroscopy (FTIR). The thermal stability of sisal fiber was analyzed by thermogravimetric analysis (TGA). The optimum tensile strength and bending strength of the composite were found at 44.0 MPa and 50.8 MPa for fiber with polyester ratio of 30 : 70, 6% NaOH concentration, and 48 h soaking time. It is confirmed that treated sisal fiber-reinforced polyester composites have better tensile and bending properties and lower water absorption than untreated fibers.