LSRE-LCM - Artigos em Livros de Atas (participação em conferências)
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- Comparison of cytochrome c with conventional biocatalysts in the degradation of environmental toxicantsPublication . Lagoa, Ricardo; Lopes, João M.; Rodrigues, J. Rui; Marques-da-Silva, DorindaPeroxidases and laccases are amongst the most attractive enzymes for the degradation of concerning pollutants like polycyclic aromatic hydrocarbons (PAHs) and organic dyes. In spite of the availability of high activity enzymes, their applicability is hindered by specificity and stability limitations in real environmental conditions, so more suitable biocatalysts are demanded. Cytochrome c (Cc) is best known as a protein electron carrier at mitochondria, but it also displays (pseudo-)peroxidase activity. In this work, we aimed to evaluate the potential of Cc as biocatalyst of PAHs’ and azo dyes’ degradation and compare it with two more conventional enzymes - plant peroxidases and fungi laccases. The studies were carried out with Cc from horse heart, horseradish peroxidase (HRP) and laccase from Trametes versicolor. The enzymes were tested with two major PAHs, anthracene and benzo[a]pyrene (BaP), and with methyl orange (MO) as a model azo dye. The enzyme-catalyzed oxidation of PAHs was determined by HPLC, and MO decolorization was followed in spectrophotometric kinetic assays. Several degradation studies were performed to assess the catalytic capacity at different pH and the effect of the redox mediator ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)). Peroxidase reactions of HRP and Cc were initiated with 100 μM H2O2 (in media containing 100 μM DTPA as metal chelator). In pH 5 acetate buffer, the specific ABTS-oxidizing activity of Cc was much lower than that of laccase and HRP. However, these two enzymes lost almost all activity at pH 7, while Cc exhibited catalytic activity even at pH 8 (phosphate buffer). Decolorization assays showed laccase alone to be a weak catalyst of MO degradation, although addition of ABTS to the reaction media greatly accelerated the transformation. On the contrary, both HRP and Cc directly catalyzed MO decolorization, including at neutral pH, and the redox mediator offered no advantage. As for the PAHs, HRP and laccase catalysis benefited from the presence of ABTS in the media, but again Cc oxidized anthracene and BaP directly. Indeed, 24h incubation of BaP (1 mg/L) with Cc (0.1 mg/mL) resulted in the transformation of 70±4% of the PAH and generation of major reaction products different of the BaP quinones produced by laccase- and HRP-ABTS systems. This work disclosed catalytic properties of Cc different from laccase and HRP that are relevant for the design of new enzymatic remediation processes.
- Design of Pyrolysis System to Convert Waste Plastic to FuelsPublication . Oliveira, Nelson S.; Pardo, Michael; Capela, Carlos; Gaspar, Marcelo; Vasco, Joel; Heleno, LizeteThe conventional recycling technology to process waste plastic, mechanical recycling, is not suitable to recycle waste thermoplastic with high content of contamination. Pyrolysis is a promising technology since it can convert into valuable products, such as fuels and monomers. This study focused on the design of the pyrolysis equipment for waste plastic based on polyolefins. The feeder of waste plastic is a worm screw conveyor that will be in a pre-heating system. The batch reactor has support for catalyzer and can operate between 300 up to 600 ºC with attached induction system for heating. The output flows into condenser in series to separate two liquid phases and gases, depending on its boiling point. The 3D model was done with SolidWorks, control system modelled in CADe SIMU and particle simulation with FloXpress.
- Energy Efficiency and Sustainability in an Aquaponic Greenhouse Supported by IoTPublication . Galvão, João; Santos, Pedro; Aires, Luis; Ribeiro, Vânia; Neves, FilipeThe increasing demand for agricultural crops and the necessity to reduce environmental impacts from traditional agriculture have led to the emergence of sustainable production systems such as hydroponics and aquaponics. These soil and pesticide-free systems require less water and fertilizers but need electrical energy and controlled greenhouse environmental conditions to be highly productive. This work presents a monitoring and management system for environmental parameters inside an aquaponic greenhouse, that allows the manager to assess in real-time the working status of the aquaponic system, helping in the detection of critical conditions that require a quick decision. This system was developed to measure, through IoT sensors network, the temperature and the relative humidity of the air, the temperature, pH and the electrical conductivity of the water that contains the dissolved nutrients that feed the growth of the plants. It is possible to visualize the measured parameters via the Internet, on a dashboard, in a mobile application and store these variables in a database. To further increase the sustainability of the aquaponic greenhouse, the electricity consumed during its activity will be produced locally by photovoltaic technology. The technologies proposed in this work may promote the emergence of small models of greenhouses, implemented by communities and populations, reducing production energy costs and transportation resources.
- Feasibility Study of the PET Fines Incorporation into Recycling ProcessesPublication . Nascimento, Bruna Guilherme do; Bozzola, Fernando; Vasco, Joel C.; Parnigoni, Milena; Capela, Carlos; Heleno, Lizete; Gaspar, Marcelo; Oliveira, Nelson S.Circular economy principles focus on the need to preserve natural resources and foster the use of environmentally sustainable practices. Concerning the use of plastics in a circular economy, increasingly demanding solutions have to be developed towards the zero-waste goal sought after by researchers and society alike. Particular attention has been put into the recycling of PET, mainly due to its wide spectrum of use and, consequently, to large volumes of related waste. The PET mechanical recycling process requires these waste materials to be shredded into PET flakes. Following such a procedure, these flakes are pelletized to be used again as feedstock. Considering the main stages of the mechanical recycling processes, which include plastic screening, shredding and washing, significant amounts of end waste materials are generated. This end-waste integrates small scale particles that are designated by plastic fines. Concerning the PET recycling process, the PET fines resulting from its mechanical recycling are not currently valued due to several technical issues, such as their high contamination level and the complexity of sorting them from other small-size particles. Current research focuses on the feasibility of incorporating these PET fines into the film/injection extruders, avoiding this way the need for an intermediate pelletization stage. To allow for such direct incorporation of PET fines into recycling processes, different decontamination and sorting solutions were implemented and tested. The current study is based on analyzing the mechanical properties of PET fines, using laboratory tests such as FTIR, DSC, MFI, moisture content, tensile tests and bending tests. Preliminary results allow foreseeing the successful direct incorporation of PET fines into PET recycling.
- Ink Removal on Plastic Films Printed by FlexographyPublication . Bozzola, Fernando; Nascimento, Bruna Guilherme do; Vasco, Joel C.; Silva, Nelson; Lagoa, Fernando; Capela, Carlos; Heleno, Lizete; Gaspar, Marcelo; Oliveira, Nelson S.Plastics are key engineering materials for our society and economy, mainly due to their multifunctionality and ease of processing. Nonetheless, their main drawback is related to the fact that when these cannot be reprocessed, they do generate waste, which leads to several environmental impacts. Therefore, considering plastics’ circularity, minimizing their waste, and the resulting impacts, stresses the need for these to be recyclable. One of the main challenges that concern their recyclability is the deinking of plastic films when printed by flexography. The current technology uses non-bio-based surfactants and non-renewable surfactants, which are harmful to the environment. Therefore, the main objective of current research is to develop an environmentally sustainable process for ink removal on printed post-industrial flexible plastic films using bio-based surfactants. This process focuses on obtaining a deinked plastic that may be reprinted, avoiding this way for inappropriate disposal or reprocessing problems. The value increase of upcycling such post-industrial waste makes it possible to match the quality of the virgin plastic, which is key to carrying out an effective cost analysis of recycled plastic when compared to the new plastic films. Dedicated laboratory deinking procedures were undertaken with transparent polyethylene films printed by flexography with different conditions. Preliminary results show the dedicated experimental ink removal procedure using bio-based surfactants to be effective and environmentally sustainable.
- Oxidative Stress and Inflammatory Response of Skin Fibroblasts Exposed to ChlorpyrifosPublication . Silva, Zélia; Almeida, Danielle; Marques-da-Silva, Dorinda; Lagoa, Ricardo; Videira, Paula A.Chlorpyrifos (CPF) is a widely used insecticide. The aim of this work was to study the effect of CPF in skin fibroblasts exposed to concentrations detected in human skin and unleash underlying cellular mechanisms. Fibroblasts were exposed to different concentrations (0.36–250 µM) of CPF pure alone or in a commercial CPF mixture (Lethal 20) for 6 days. In conclusion, prolonged exposure to 250 µM of CPF pure and 125 µM of Lethal 20 caused a significant loss of the fibroblast´s viability. Moreover, the toxicity of this pesticide in fibroblasts is evidenced by the induction of oxidative stress and stimulation of the production of interleukin (IL)-6.
- Permeation of chlorpyrifos in ex vivo pig skin – Experimental conditions to get closer to human exposurePublication . Silva, DorindaTrack 3: Environmental chemistry and exposure assessment: analysis, monitoring, fate and modeling 3.06.P-Tu151 Permeation of Chlorpyrifos in Ex Vivo Pig Skin - Experimental Conditions to Get Closer to Human Exposure to air pollutants is not limited to inhalation risk and dermal contact is gaining increasing interest with the possibility to represent a risky carcinogenic route. Chlorpyrifos is a broad-spectrum organophosphorus pesticide used for aerial and ground-based treatments with different permeation values being reported for human skin. Despite the recommendations of the organisation for economic co-operation and development (OECD) to use 50% of ethanol in the receptor fluid for skin permeation of lipophilic compounds (as chlorpyrifos), this condition was suggested to exaggerate its permeation.
- Production and Material Types for Pallets: A ReviewPublication . Pulgar, Alejandro; Oliveira, Nelson S.Pallets are used extensively in the supply chain for the transportation of goods between suppliers, manufacturers, distributors, and retailers. This article reviews pallet production, its mechanical properties related to material options (according to European standards and industrial applications) and management systems. In the global supply chain, polymer, metal, and composites pallets compete in line with the concept of sustainable development. The supply chain requires pallets according to specific characteristics, such as sizing, maximum load capacity, durability (lifespan), cost and more information is needed about their environmental impacts. Some types of pallets (stringer and blocks) can have several configurations, number, width and spacing. Furthermore, the pallets management system is divided in three models; EMP (extensive management of pallets), TPO (transfer pallet’s ownership) and PR (pallet rent), where suppliers, distributors and retailers select the most suitable option. The systematic review of the literature identified 15 documents with the key methodological elements, such as, specifications, inventory data, goals, and system boundaries for a life cycle assessment of pallets.
- Promotion of Dermal Permeation of Bioactive Compounds Using a Microneedle DevicePublication . Violante, Cristiana; Lagoa, Ricardo; Marques-da-Silva, DorindaSeveral natural bioactive compounds are described for their beneficial effects to skin. Nevertheless, for some compounds, dermal absorption is a challenge, demanding new methods to enhance skin penetration. In this work, pre-treatment with a microneedle device was tested to promote the permeation of caffeine and epicatechin through ex vivo pig skin. The results indicated that the microneedle pre-treatment increased the permeation of both compounds at a similar range. Compared to untreated skin, more than 20% higher amounts of caffeine and epicatechin crossed the treated skin. The data support the application of microneedle systems to promote the dermal delivery of bioactive compounds.
- Qualitative analysis of the limestone waste potential from the Serra de Aire e Candeeiros quarriesPublication . Monteiro, S. M. C. S.; Jorge, Muanassa; Oliveira, N. S.; Alves, M.L.; Veiga, A.; Silva, A.The mountains of Aires and Candeeiros are part of the Maciço Calcário Estremenho where the landscape is predominantly made up of limestone. The limestone explored in the region has been the driver of social and cultural development, contributing significantly to the local economy. This emerging concern has motivated public and private organisations to develop solutions to improve the sector's sustainability. The present work aims to evaluate the limestone waste potential to produce precipitated (PCC) and ground (GCC) calcium carbonate in the region by surveying the local extraction industries that fulfil the defined minimum requirements to produce high quality PCC and GCC. The results allowed to stablish an estimate of the amount of waste resulting from the extraction process. The conversion of these wastes into PCC or GCC constitutes a possibility of recovery into by-products, allowing use in noble and profitable applications and contributing to the circular economy and the sustainability of the sector.