Browsing by Author "Crispim, Alfredo"
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- Adding value [valorization] to tannery fleshings: part II – effect of protein hydrolysates on leather dyeingPublication . Bragança, Idalina; Nouws, Henri P. A.; Crispim, AlfredoThe tanning industry generates a high quantity of solid wastes. Therefore, there is a need to create valorization [added value] options for these wastes. The main objective of the present work was to study the effect of protein hydrolysates (HP) prepared from fleshings on leather dyeing. During previous studies it was found that the application of HP products, obtained from fleshings, in leather retannage intensified the colour of crust leather. In this work the CIELAB colour system was used to evaluate the effect of HP on retannage processes. The main conclusions of this study were: (i) HP can be used instead of a dicyanodiamide resin (Fortan DC) if the colour parameters of the standard procedure are to be maintained, and (ii) the replacement of an acrylic resin (Fortan A40) by glutaraldehyde-modified HP (GHP) results in a darker skin, and can therefore be interesting for the reduction of the quantity of dye used.
- 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.
- 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.
- 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.
- Influence of the pre-treatments on the properties of biodegradable films from bovine hairPublication . Costa, Joana F.; Pitrez, Patrícia R.; Rocha, Cristina M. R.; Freitas, Olga M.; Crispim, Alfredo; Delerue-Matos, Cristina; Gonçalves, Maria PilarThe replacement of conventional synthetic films and coatings by biodegradable alternatives reduces the use of non-renewable resources and waste disposal problems. Considering that Portugal is a major producer of leather, and consequently a large producer of related wastes, in this research, bovine hair was tested for the production of biodegradable films directly by thermo-compression, allowing waste valorisation and reduction of environmental pollution. The aim of this study was to determine the influence of the different pre-treatments performed by two processes (removal by mechanical action and removal by chemical process), applied to bovine hair, in order to obtain a biodegradable film with appropriate properties. Mechanical properties for these films were evaluated, namely strain at break, stress at break and Young modulus. Additionally colour, solubility and swelling in water were also studied. The mechanical removal hair only produced films with Na2S treatment. Chemical removed hair (immunization) depends of the pre-treatment and the degreasing with petroleum ether or sodium sulphide pre-treatment leads better mechanical properties. The results obtained indicated that the pre-treatments have an important role in the final properties of biodegradable films.
- 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]. [...]
- 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
- 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.