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- New approaches to olive mill wastes bioremediationPublication . Duarte, José Cardoso; Pires, Susana; Paixão, Susana M.; Sáágua, M. C.Remediation of olive mill wastewater (OMW) is an important issue associated with olive-oil manufacturing, a widespread activity in the Mediterranean area. This high organic loading effluent contains water, organic acids, high-molecular-weight polyphenols such as tannins, antocyanins and catechins, which are considered to be responsible for its brownish black colour and ecotoxic properties. The composition of OMWs is highly variable with respect to each individual component, depending on the process conditions and on the agricultural specificities. Thus, different approaches are applicable concerning to OMW treatment and valorisation , considering the specificities of its production and in particular the oil extraction process. Besides there are several physical, physico-chemical, biological and combined processes to OMW detoxification, each may represent an opportunity for a specific condition. It is important to explore new possibilities that are both environmentally sustainable and economically viable. Under the biological processes the use of fungi and in particular white-rot fungi present a potential interesting alternative for depollution and biological chemicals production or for protein production for feeding. In this aspect we have been testing the ability of a “white-rot” fungus, Bjerkandera paranensis, to use undiluted OMW from a two phase process mill. A chronic ecotoxicity test (Vibrio fisheri growth inhibition test) demonstrated that the growth of this fungus contributed for a significant decrease of the OMW ecotoxicity and demonstrating the potential for further studies with this strain for an alternative biological route to OMW treatment and valorization.
- Indoor air quality in primary schoolsPublication . Freitas, Maria do Carmo; Canha, Nuno; Martinho, Maria; Almeida-Silva, Marina; Almeida, S. M.; Pegas, Priscilla; Alves, Célia; Pio, Casimiro; Trancoso, Maria Ascensão; Sousa, Rita; Mouro, Filomena; Contrira, Teresa
- Deconstruction of the hemicellulose fraction from lignocellulosic materials into simple sugarsPublication . Gírio, Francisco; Carvalheiro, Florbela; Duarte, Luís C.; Lukasik, Rafal M.Hemicelluloses hold a great promise for the production of added-value compounds in the biorefinery framework. Specifically, the xylan-rich hemicelluloses from hardwoods and agro-industrial residues present themselves as effective feedstock choices for the biotechnological production of xylitol. This paper reviews the various hemicellulose structures present in such materials and critically evaluates the available processing options to produce xylose-rich fermentable hydrolysates. Currently, acid-based processes still present the best trade-off between operation easiness and xylose yield and recovery. Nevertheless, concerns regarding the impact of the fractionation processes on the overall upgradability of all biomass fractions (namely, cellulose and specially lignin) may turn the route to other strategies. Specifically, the combined/sequential use of processes targeting hemicellulose dissolution and hydrolysis might hold great promise for the economical production of pentoses.
- Ionic liquidsPublication . Lukasik, Rafal M.; Bogel-Lukasik, EwaIonic liquids (ILs) are a group of interesting compounds that have been known for more than a century, attracting major attention within the last two decades. ILs are often confused with molten salts. ILs are salts with the melting point arbitrarily determined to be below 100°C. They are composed of ions and, thus, each IL possesses unique properties that are the effect of a cation and an anion‘s nature. However, in general, ILs are characterized by a low melting point, high thermal and chemical stability, a large electrochemical window, great solvent power, nonflammability and a negligible vapor pressure. Density and viscosity, as well as many other properties, can easily be tuned as they are dependent on the chemical structure of the IL. Therefore, the ‘designer solvent‘ can be created for many applications, including biotransformation, chemical reactions (e.g., catalysis and hydrogenation), biorefinery concept, extraction and separation, and others.
- Integration of polymeric-base wastes into petroleum refineriesPublication . Miranda, Miguel; Cabrita, Isabel; Alvarez, Nuno; Gulyurtlu, IbrahimThe continuous growth of world population along with incresing needs to improve life quality of societies and their dependence on fuel and other derived petroleum products suggest that the overall energy demand will increase significantly in the future. This chapter focuses the production of liquid fuels by pyrolysis applied to rubber tyre and diffetent plastic wastes as an option for integration in the refining process. The advantage is that pyrolysis of polymeric-base wastes tends to reverse the polymerization process used in the production of polymers at moderate conditions of temperature and pressure. The liquids obtained depend upon the polymeric blend. Products yields could lead to liquids similar to petroleum derived fuels as well as chemical feedstocks suitable to a wide range of industries. Considering that it is innivative the integration of polymeric-base wastes streams in petroleum refineries, a more detailed analysis on issues related to retrofitting will be presented.
- Advances in the reduction of the costs inherent to fossil fuels’ biodesulfurization towards its potential industrial applicationPublication . Paixão, Susana M.; Arez, B. F.; Silva, Tiago; Alves, LuísBiodesulfurization (BDS) process consists on the use of microorganisms for the removal of sulfur from fossil fuels. Through BDS it is possible to treat most of the organosulfur compounds recalcitrant to the conventional hydrodesulfurization (HDS), the petroleum industry’s solution, at mild operating conditions, without the need for molecular hydrogen or metal catalysts. This technique results in lower emissions, smaller residue production and less energy consumption, which makes BDS an eco-friendly process that can complement HDS making it more efficient. BDS has been extensively studied and much is already known about the process. Clearly, BDS presents advantages as a complementary technique to HDS; however its commercial use has been delayed by several limitations both upstream and downstream the process. This study will comprehensively review and discuss key issues, like reduction of the BDS costs, advances and/or challenges for a competitive BDS towards its potential industrial application aiming ultra low sulfur fuels.
- Dark fermentative hydrogen production: from concepts to a sustainable productionPublication . Moura, Patrícia; Ortigueira, Joana; Valdez-Vazquez, Idania; Saratale, Ganesh D.; Saratale, Rijuta G.; Silva, Carla M.ABSTRACT: The use of renewable sources and environmentally friendly processes is considered a priority for the construction of a sustainable energy future. The harmful impact of fossil fuels and the fact that we are reaching a disrupting point regarding environmental damage require the rapid implementation of new energy systems and a substantial increase in the use of alternative, unconventional energy sources. Hydrogen (H2) is considered one of the most promising sources as a clean energy vector, because of its high energy density (120 MJ/kg) and carbon-free combustion (Argun and Kargi, 2011). Hydrogen is the simplest and most abundant element on earth; however, it barely exists in nature in its molecular state. Instead, it is almost always found as part of other compounds from which it should be separated, either by thermochemical processes or through biological conversion.
- Measurement of total reactive phosphorus in natural water by molecular spectrophotometry (SMEWW 4500-P D)Publication . Silva, Ricardo Bettencourt da; Trancoso, Maria Ascensão; Teixeira, P. Alexandra; Oliveira, Cristina M. R. Ramiro de; Mosca, Alice I. de Jesus; Dias, Florbela A. do Sacramento; Camões, M. Filomena G. F. CrujoABSTRACT: Phosphorus occurs in natural waters almost solely as phosphates.
- Advances in the reduction of the costs inherent to fossil fuel biodesulfurization towards its potential industrial applicationsPublication . Paixão, Susana M.; Silva, Tiago; Arez, B. F.; Alves, LuísABSTRACT: The biodesulfurization (BDS) process consists of the use of microorganisms for the removal of sulfur from fossil fuels. Through BDS it is possible to treat most of the organosulfur compounds recalcitrant to the conventional hydrodesulfurization (HDS), the petroleum industry's solution, at mild operating conditions, without the need for molecular hydrogen or metal catalysts. This technique results in lower emissions, smaller residue production, and less energy consumption, which makes BDS an eco-friendly process that can complement HDS making it more efficient. BDS has been extensively studied and much is already known about the process. Clearly, BDS presents advantages as a complementary technique to HDS; however, its commercial use has been delayed by several limitations both upstream and downstream the process. This study will comprehensively review and discuss key issues, like reduction of the BDS costs, advances, and/or challenges for a competitive BDS towards its potential industrial application aiming ultra-low sulfur fuels.
- Advances in the reduction of the costs inherent to fossil fuel biodesulfurization towards its potential industrial applicationsPublication . Paixão, Susana M.; Silva, Tiago; Arez, B. F.; Alves, LuísABSTRACT: The biodesulfurization (BDS) process consists of the use of microorganisms for the removal of sulfur from fossil fuels. Through BDS it is possible to treat most of the organosulfur compounds recalcitrant to the conventional hydrodesulfurization (HDS), the petroleum industry's solution, at mild operating conditions, without the need for molecular hydrogen or metal catalysts. This technique results in lower emissions, smaller residue production, and less energy consumption, which makes BDS an eco-friendly process that can complement HDS making it more efficient. BDS has been extensively studied and much is already known about the process. Clearly, BDS presents advantages as a complementary technique to HDS; however, its commercial use has been delayed by several limitations both upstream and downstream the process. This study will comprehensively review and discuss key issues, like reduction of the BDS costs, advances, and/or challenges for a competitive BDS towards its potential industrial application aiming ultra-low sulfur fuels.