Browsing by Author "Pinto, Vera"
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- Assessing the influence of oil and grease and salt content on fish canning wastewater biodegradation through respirometric testsPublication . Cristovão, Raquel; Pinto, Vera; Martins, Ramiro; Loureiro, José M.; Boaventura, RuiFish canning industry wastewaters have high organic matter, oil and grease and salt (NaCl) content, which make difficult a proper treatment before discharge. In this work, their treatment was evaluated via activated sludge aerobic biological process through respirometric tests. Inhibition was found to be significant for NaCl concentr ations higher than 17.5 g/L. On the other hand, the oil and grease content affects the wastewater biodegradability in the same way that the organic matter content expressed as chemical oxygen demand: the lower oil and grease and organic matter concentrations, the lower the percentage of wastewater biodegradability. As a final conclusion, the aerobic biological treatment process by activated sludge proved to be appropriate to treat fish canning industrial wastewaters, leading to high organic matter degradation rates (average value of 4900 mg O2 /g COD .d). Additionally, the experimental results achieved with the respirometric tests may be useful for the design of activated sludge plants to treat this type of wastewaters.
- Biobased additives as biodegradability enhancers with application in TPU-based footwear componentsPublication . Fernandes, Isabel P.; Barbosa, Mariana Martinho; Amaral, Joana S.; Pinto, Vera; Rodrigues, José Luís; Ferreira, Maria José; Barreiro, M.F.Among the wide variety of materials employed in the manufacture of shoes, thermoplastic polyurethanes (TPUs) are one of the most widely used. Given its widespread use, and associated waste management problems, the development of more biodegradable and evironmentally compatible solutions is needed. In this work, a polyester-based TPU used in the footwear industry for outsoles production was modified by compounding with lignin, starch and cellulose at content of 4% (w/w). The biodegradability was evaluated by using agar plate tests with the fungi Aspergillus niger ATCC16404, the Gram-negative bacteria Pseudomonas aeruginosa ATCC9027 and an association of both (consortium), and soil tests at 37 °C and 58 °C. The obtained results evidenced a positive effect of the tested biobased additives, the most favourable results being registered with lignin. These results were corroborated by the structural modifications observed by FTIR analysis. Additionally, mechanical tests prove the suitability of using the lignin modified TPUs for footwear outsoles production.
- Chitosan as an antimicrobial agent for footwear leather componentsPublication . Barros, Maria Catarina; Fernandes, Isabel P.; Amaral, Joana S.; Barreiro, M.F.; Pinto, Vera; Ferreira, Maria JoséIn the footwear industry, microorganisms’ growth can pose problems of material deterioration with associated unpleasant smell and generate possible infections in susceptible individuals. Generally, footwear presents high relative humidity conditions that enable the growth of bacteria and fungi. Additionally, leather itself and some tannery agents such as oils and greases, provide a substrate where microorganisms can grow. In the foot, microtraumas caused by ingrown nails, abrasions and lacerations can allow microbial invasion through epidermis, resulting in skin infection. In this work, the applicability of chitosan functional coatings to leather was tested, with the purpose to develop new base materials to produce footwear components. The leather treated with chitosan was then studied for its antibacterial properties against 3 different bacteria.
- Chitosan as an antimicrobial agent for footwear leather componentsPublication . Barros, Maria Catarina; Fernandes, Isabel P.; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.; Amaral, Joana S.Chitosan is being increasingly used in distinct areas such as pharmaceutical, biomedical, cosmetics, food processing and agriculture. Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one to generate the higher number of applications. Within this work the role of chitosan in diverse applications has been reviewed with particular emphasis for those exploring its antimicrobial power. Furthermore, the mechanism to explain the antimicrobial activity of this emerging biopolymer is also discussed. The viability of using chitosan to effectively provide a functional coating for leather products was presented through an experimental case study. Results confirmed the potential of using this strategy to create antimicrobial leather products to be used, e.g., in the footwear industry.
- Chitosan microparticles loaded with essential oils having in view leather applicationsPublication . Fernandes, Isabel P.; Amaral, Joana S.; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.Chitosan is a biopolymer attracting considerable attention for diverse applications due to its unique properties like biodegradability, biocompability, non-toxicity and antimicrobial activity. It is obtained by the partial N-deacetylation of chitin, which is the second most abundant polysaccharide in nature, next to cellulose. Chitosan is a viable base material for functional coatings development, namely due to its antimicrobial activity. This characteristic is especially useful for footwear applications that constitute products prone to microbial attack. In this context, developing antimicrobial coatings to be used in footwear components in direct contact with the feet are of great interest, both at industrial level (reducing possibility of material deterioration and quality loss), as well as, from the consumer’s point of view (decrease of skin infections and minor unpleasant odours). Following our previous work, where leather impregnation with chitosan was studied at laboratorial level with quite promising results, and having in view the final application (footwear leather components), where the antimicrobial effect must need to be enhanced, we have developed the idea of microencapsulate different essential oils, with recognized antimicrobial activity like lemon, oregano, eucalyptus and pine. These chitosan-based microparticles, loaded with the chosen essential oil are intended to be applied conjunctly with the chitosan coating process previously studied. Microencapsulation will ensure that the loaded core material will be progressively released, reinforcing the antimicrobial durability and effectiveness of the final product.
- Chitosan-based antimicrobial leather coatings : evaluation of the pilot scale productionPublication . Fernandes, Isabel P.; Barreiro, M.F.; Pinto, Vera; Ferreira, Maria José; Amaral, Joana S.Chitosan is a biopolymer that is being increasingly used in distinct areas such as pharmaceutical, biomedical, cosmetics, food industry and agriculture. Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Considering that feet present favorable conditions for microorganism’s growth due to the high relative humidity conditions, warmth and nutrients availability (from feet sweat), one of such applications can be the use of chitosan to provide an antimicrobial coating for leather footwear components. Previous studies, in which leather impregnation with chitosan was performed at laboratory scale, showed that samples presented antimicrobial activity against Gram-positive and Gram-negative bacteria. In this work, the antimicrobial activity of chitosan-based leather coatings, produced at a pilot scale, was evaluated.
- Chitosan-based antimicrobial leather coatings: evaluation of the scale productionPublication . Fernandes, Isabel P.; Barreiro, M.F.; Pinto, Vera; Ferreira, Maria José; Amaral, Joana S.Chitosan is a biopolymer that is being increasingly used in distinct areas such as pharmaceutical, biomedical, cosmetics, food industry and agriculture. Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Considering that feet present favorable conditions for microorganism’s growth due to the high relative humidity conditions, warmth and nutrients availability (from feet sweat), one of such applications can be the use of chitosan to provide an antimicrobial coating for leather footwear components. Previous studies, in which leather impregnation with chitosan was performed at laboratory scale, showed that samples presented antimicrobial activity against Gram-positive and Gram-negative bacteria. In this work, the antimicrobial activity of chitosan-based leather coatings, produced at a pilot scale, was evaluated.
- Chitosan-based leather functional coatings with improved antimicrobial propertiesPublication . Amaral, Joana S.; Fernandes, Isabel P.; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Developing antimicrobial coatings for footwear components to be used in direct contact with the feet is of great interest; both at industrial level (reducing the possibility of material deterioration and quality loss) and from the consumer’s point of view (decreasing skin infections and minimizing unpleasant odours). One weakness of this application is addressed to the durability and efficiency of the product antimicrobial activity, since it is directly associated with the availability of the positively charged R–NH3 + groups that are depleted during use.
- Cork-based composites: studies on binder replacement and incorporation of biomass-derived additivesPublication . Rafael, Helder Martins; Fernandes, Isabel P.; Nunes, Bernardo; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.; Rafael, Helder MartinsThe Portuguese footwear industry is an important economic sector once it is one of the most active national business areas. The investment made in the production of footwear with high technological performance, and high technical-scientific requirements, evidences the valorization of the footwear industry during the last years. In addition, the evolution of consumers' environmental awareness, allied to the demand for bio-products, is considered a challenge for this sector. Therefore, the development of novel composites, based on natural materials and by adopting green productive processes, represents an area of great interest. In fact, cork, the natural material selected for this application, has properties such as impermeability, good compressibility and resilience, as well as low density, being usually applied in the form of composites for the production of footwear components like shoe insoles and soles. Cork is the bark of a cork oak (Quercus suber L.), which is normally harvested every 9-12 years. Among the corkproducing countries, Portugal has the largest annual production, with around 100.000 tons, which represented 49.6% of the worldwide production in 2016. Traditionally, the cork agglomeration process uses a reactive polyurethane-based adhesive, which results on composites with low flexibility and poor water absorption/desorption characteristics, generating products with low comfort properties. In addition, this adhesive is based on toluene diisocyanate (TDI), which is classified as a high toxic compound, thus motivating its replacement by environmental friendly products. Herein, the use of green adhesives such as water-based polyurethanes dispersions can be envisaged. Furthermore, the low water absorption capacity of the generated composites is related to the hydrophobic character of the cork itself and the used binder, which results in low absorption of the sweat, promoting a sensation of discomfort when footwear incorporating these materials is used. Considering all the above mentioned, the present work is focused on the production of novel cork-based composites, where the traditionally used adhesive was replaced by commercial water-based polyurethane adhesives. In addition, the effect of incorporating residual biomasses on the water absorption/desorption properties will be tested.
- Development of a prototype to access biodegradability of TPU shoe soles under controlled conditionsPublication . Fernandes, Isabel P.; Barbosa, Mariana Martinho; Amaral, Joana S.; Pinto, Vera; Ferreira, Maria José; Barreiro, M.F.In the last years, the increasing problems posed by waste management have stimulated the interest in developing more sustainable and bio-based solutions for the footwear industry, including the use of biodegradable materials. As part of the NEWALK project, the objective of this work consisted in optimizing and implementing a respirometry system prototype. Besides evaluating different variables, two different approaches for measuring the evolved CO2 were assayed. Compared to manual titration, the use of conductivity offers the advantage of an automatic continuous monitoring.