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- Adding Value to Tannery Fleshings Part I – Oils and Protein Hydrolysates – Production and ApplicationPublication . Bragança, I.; Crispim, Alfredo; Sampaio, A.; Ramalho, Elisa; Crispim, F.; Caetano, Nídia; Silva, P. C.The tanning industry generates a high quantity of solid wastes. Therefore, there is a need to create valorization [added value] options for these wastes. The present work had as its main objective creating added value by production of fat and hydrolyzed protein. To this end, fleshings were treated by hydrolysis with regard to the influence of various factors. The best result was found for a temperature of 60°C, 4 hours of hydrolysis, 2% of enzyme and 100% of water, with a fat extraction yield of 93%. The fat obtained through the hydrolysis process was used to produce sulphated oils. The protein hydrolysate was concentrated to about 40% of solids content and used to prepare co-products of protein hydrolysate and glutaraldehyde. Sulphated oils were applied in leather fatliquoring and the different protein hydrolysates were tested in leather retannage. The leather samples obtained were evaluated by physical-mechanical tests and the results were compared to those obtained through a standard process. The results were very satisfactory and, in some cases better than the specified standard. The process of adding value to this waste results in a double advantage for the leather industry, reducing the environmental impact and allowing production of alternative products for leather fatliquoring and retannage.
- Valorization of Facts from animal wastes: Biodiesel productionPublication . Sampaio, Alberto; Caetano, Nídia; Ramalho, Elisa; Crispim, Alfredo; Silva, Paula CristinaTwo of the most important concerns regarding planet sustainability are energy management and waste disposal. Renewable energy sources and waste valorization processes are therefore very important. Among biofuels, biodiesel has very good utilization and environmental properties that allow partial or total replacement of diesel fuel. Biodiesel can be produced from residues like waste frying oils and animal fats. The purpose of this work is to produce biodiesel from fat obtained from industrial animal residues: green and lime fleshings from tanneries and slaughterhouses wastes. The fats were previously characterized and some of the samples presented a high acid value. For these materials, an acid esterification step prior to the transesterification reaction was needed, in order to lower the acid value. Transesterification with methanol was performed using sodium hydroxide or sodium methylate as catalysts, at 65ºC. The quality of biodiesel products was assessed by some of EN 14214 Standard parameters. The results show that most of the samples are within the specifications, except for high CFPP. This is typical of biodiesel produced from animal fats that present high saturated fatty acid content. Nevertheless, these products can be used in mixtures with biodiesel from vegetable oils, in order to meet standard specifications
- Fat extraction from fleshings - optimization of operating conditionsPublication . Cunha, A.F.; Caetano, Nídia; Ramalho, Elisa; Crispim, AlfredoFat from fleshings is an excellent source of energy since it is composed of glycerides, fatty acids and glycerol. The present work aims to optimize the operating conditions of fat extraction from fleshings. Animal fat was obtained after thermal treatment of fleshings in a stainless steel batch reactor using different operating conditions (100T155 ºC; 1P5.5 bar, t= 2 h, r= 1000 rpm). The fat containing phases were extracted in a heated Soxhlet using n-hexane and ethanol to recover the fat from the solid residue. In addition, 6 M HCl acid was added to the remaining solid and heated to boiling conditions for 2 h to further extract fat that is encapsulated in the tissues of the fleshing. The best conditions of fat extraction were obtained at 155 ºC during 2 h and 1000 rpm that generated a pressure of 5.5 bar inside the batch reactor. It was also found that significantly higher amount of fat could be obtained at the operating conditions mentioned (50 wt. % on dry basis), sparring chemical treatments by using a 6 M HCl acid for additional fat extraction. Finally, this approach allowed to significantly reduce the environmental impact of solid waste, decreasing also the costs associated with disposal, while contributing to the circular economy of the tanning sector.
- Wet-white shavings as a potential source for leather retanning bioagentsPublication . Freitas, Teresa; Marujo, I.; Ribeiro, D.; Crispim, Alfredo; Neto, Maria Paula; Gaião, J.; Oliveira, J.The tanning industry generates a high quantity of solid wastes, so there is a need to create ways to value these wastes with aim to reduce environmental impact. A lot of research work has been done recently and some authors have shown the potential for obtaining protein hydrolysates from solid wastes and its application. The present work had a main objective the wet-white shavings valorization by production of hydrolysed protein and biopolymrs for leather retanning.
- Circular economy using waste from different industries in leather retainningPublication . Alves, C.; Silva, V.F.; Crispim, Alfredo; Almeida, A.; Pinto, G.; Gaião, J.; Sousa, N.; Duarte, J.A circular economy is based on an economy that in principle, moves away from the accelerated model of consumption and disposal. Thus, the flow associated with the product, instead of being translated by a straight line, is now regarded as a circle or cycle. The leather manufacturing applies several physical and chemical treatments in different stages to transform the skin into leather. The pulp and paper industry generate several byproducts such as tannins and lignins. The sulfited lignins are a particular type of black liquor and could be used as dispersing, pre-tanning and retanning agents . During the chestnut freezing process, as consequence of the quality control, a significant quantity of chestnut fruit is rejected and not accepted by the consumer. Due to its high starch content, the chestnut fruit reject is used to produce chestnut flour which can be used as a filler retanning agent for leather. From the biodiesel process results a byproduct, which represents 10 % wt of the overall production, the crude glycerol. The hygroscopic effect of glycerol and its emulsifying and lubricant effect can be enhanced for the leather fatliquoring.
- Pyrolysis of leather wastes from the footwear industry –preliminary resultsPublication . Direito, D.; Pilão, Rosa Maria; Crispim, Alfredo; Ribeiro, A.M.Most of the leather used by the footwear industry (more than 70%) is produced from skins and hides tanned with chromium sulphate [1]. The production of leather goods, especially shoes, gives rise to wastes that amount to 15 – 20% of the entry leather [2]. As an example, the European footwear industry generates between 1x105 to 2x105 tons per year of leather wastes [1]. In the last few years, various investigations have been carried out in order to find alternatives to the disposal of these residues in landfills. Several processes have been developed to treat the leather residues that include, among others, combustion, pyrolysis, chemical treatment (oxidation and hydrolysis) or direct application of the wastes [2]. Pyrolysis is the thermal degradation of wastes, in the presence of an inert atmosphere, producing a solid phase (biochar), a liquid phase (bio-oil) and a gas phase composed mainly of CO2, CO, CH4 and H2 [3]. Several authors have reported work on the pyrolysis of chromium tanned leather wastes [4, 5, 6]. [...]
- Wet-blue retanning process optimization for reducing water and energy consumption, and environmental impactPublication . Filipe, T.; Alves, C.; Freitas, T.; Crispim, A.; Dias, S.The process of transforming animal skin into leather comprises a range of chemical processes and mechanical operations that can be divided in four sectors such as beamhouse, tanning, dyeing, and finishing. In the dyeing sector, the chemical process (normally called retanning or dyeing process) has four main steps: neutralization, retanning, dyeing, and fatliquoring. A very important part of research in field of tanning industry is focused on develop and adapt alternative and clean processes, contributing to the sustainability of the planet. These new processes and methods enable an improvement of the quality of the leathers obtained while achieving a reduction in the energy and water consumption, as well as pollution generated.
- Footwear leather waste treatment: Energetic alternative ways against landfill disposalPublication . Alves, C.; Marques, D.; Crispim, A.(Introduction) Leather finished wastes resulting from the footwear manufacturing process are generated. Most of this waste is contaminated with chromium. Energetic valorization is one alternative to landfilling that must be evaluated, taking into account the current importance of energy. In this way, three technologies can be compared to evaluate this alternative: incineration, gasification, and pyrolysis. In recent years, a lot of research work has been done to evaluate the application of these technologies to leather solid waste.
- Leather wastes as a potential source of biochemicals and biomaterialsPublication . Dias, R.; Crispim, A.; Silva, P.; Neto, P.; Gaião, J.; Oliveira, J.Framework: Leather industry is one of the oldest and most traditional industries, although it produces high amount of solid waste and wastewater; • Only 20% of the of the hide results in finished leather products • Annually, 41,000 tons of organic solid waste are generated in Portugal; • From an economical and environmental point of view, there is a great interest in the valorisation of the generated solid wastes.