Extraction and characterization of microplastics from portuguese industrial effluents

Microplastics (MPs) are contaminants present in the environment. The current study evaluates the contribution of different well-established industrial sectors in Portugal regarding their release of MPs and potential contamination of the aquifers. For each type of industry, samples were collected from wastewater treatment plants (WWTP), and different parameters were evaluated, such as the potential contamination sources, the concentration, and the composition of the MPs, in both the incoming and outcoming effluents. The procedures to extract and identify MPs in the streams entering or leaving the WWTPs were optimized. All industrial effluents analysed were found to contribute to the increase of MPs in the environment. However, the paint and pharmaceutical activities were the ones showing higher impact. Contrary to many reports, the textile industry contribution to aquifers contamination was not found to be particularly relevant. Its main impact is suggested to come from the numerous washing cycles that textiles suffer during their lifetime, which is expected to strongly contribute to a continuous release of MPs. The predominant chemical composition of the isolated MPs was found to be polyethylene terephthalate (PET). In 2020, the global need for PET was 27 million tons and by 2030, global PET demand is expected to be 42 million tons. Awareness campaigns are recommended to mitigate MPs release to the environment and its potential negative impact on ecosystems and biodiversity.info:eu-repo/semantics/publishedVersio

Microplastics in ecosystems: from current trends to bio-based removal strategies

Plastics are widely used due to their excellent properties, inexpensiveness and versatility leading to an exponential consumption growth during the last decades. However, most plastic does not biodegrade in any meaningful sense; it can exist for hundreds of years. Only a small percentage of plastic waste is recycled, the rest being dumped in landfills, incinerated or simply not collected. Waste-water treatment plants can only minimize the problem by trapping plastic particles of larger size and some smaller ones remain within oxidation ponds or sewage sludge, but a large amount of microplastics still contaminate water streams and marine systems. Thus, it is clear that in order to tackle this potential ecological disaster, new strategies are necessary. This review aims at briefly introducing the microplastics threat and critically discusses emerging technologies, which are capable to efficiently clean aqueous media. Special focus is given to novel greener approaches based on lignocellulose flocculants and other biomaterials. In the final part of the present review, it was given a proof of concept, using a bioflocculant to remove micronized plastic from aqueous medium. The obtained results demonstrate the huge potential of these biopolymers to clean waters from the microplastics threat, using flocculants with appropriate structure.UIDB00102/2020/ UIDB/05183/2020/ PTDC/AGR-TEC/4814/2014/ PTDC/ASP-SIL/30619/2017/ CEECIND/01014/2018info:eu-repo/semantics/publishedVersio

Acacia wood fractionation using deep eutectic solvents: extraction, recovery, and characterization of the different fractions

The selective extraction and recovery of different lignocellulosic molecules of interest from forestry residues is increasing every day not only to satisfy the needs of driving a society toward more sustainable approaches and materials (rethinking waste as a valuable resource) but also because lignocellulosic molecules have several applications. For this purpose, the development of new sustainable and ecologically benign extraction approaches has grown significantly. Deep eutectic solvents (DESs) appear as a promising alternative for the processing and manipulation of biomass. In the present study, a DES formed using choline chloride and levulinic acid (ChCl:LA) was studied to fractionate lignocellulosic residues of acacia wood (Acacia dealbata Link), an invasive species in Portugal. Different parameters, such as temperature and extraction time, were optimized to enhance the yield and purity of recovered cellulose and lignin fractions. DESs containing LA were found to be promising solvent systems, as the hydrogen bond donor was considered relevant in relation to lignin extraction and cellulose concentration. On the other hand, the increase in temperature and extraction time increases the amount of extracted material from biomass but affects the purity of lignin. The most promising DES system, ChCELA in a ratio of 1:3, was found to not significantly depolymerize the extracted lignin, which presented a similar molecular weight to a la-aft lignin. Additionally, the P-31 NMR results revealed that the extracted lignin has a high content of phenolic OH groups, which favor its reactivity. A mixture of ChCl:LA may be considered a fully renewable solvent, and the formed DES presents good potential to fractionate wood residues.info:eu-repo/semantics/publishedVersio

Eco-friendly methods for extraction and modification of cellulose: an overview

Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose’s use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed.BDE 05|POCI-01-0247-FEDER021874; 2022.07519.PTDCinfo:eu-repo/semantics/publishedVersio

The Influence of Particle Size Distribution on the Performance of Ceramic Particulate Suspensions

During the preparation of ceramic glaze suspensions it is necessary to guarantee that the suspension possesses the required properties, with several parameters having to be rigorously controlled, e.g., particle size and solids concentration, composition of the suspension and ionic charge of the liquid. This study focuses attention on the influence of particle size distribution on three important properties of glaze suspensions: rheological behavior, opacity and reflectance characteristics and tendency to dissolve. In this paper, results are presented for two glaze formulations prepared with two different commercial frits of distinct composition. The glazes were prepared in a laboratory ball mill and the grinding time was adjusted for each formulation, in order to obtain suspensions with different particle size (at least three different grinding times). The rheological behavior is strongly dependent on the particle size and also on changes in the interactions between the particles, caused by modifications in the cationic content of the suspending medium, as a result of frit dissolution, which is also influenced by the size of the particles

Transporte Hidráulico de Sólidos: Estudo do Mecanismo de Suspensão

Neste trabalho apresenta-se um contributo para o esclarecimento dos fenómenos que provocam a suspensão dos sólidos durante o escoamento, em regime turbulento, de suspensões sólido/líquido no interior duma conduta horizontal. O modelo adoptado para descrever os fenómenos presentes é o da dispersão/sedimentação. A primeira secção do trabalho incide sobre a previsão, recorrendo ao modelo proposto, da distribuição dos sólidos na conduta. Os resultados da simulação são confrontados com valores experimentais existentes na literatura. Na segunda secção do trabalho efectua-se um estudo experimental da dependência dos parâmetros do modelo em ordem às condições locais do escoamento (velocidade e concentração dos sólidos)

Talking about Teaching 2012

The Portuguese Society for Engineering Education (SPEE) was publically launched in 2010. Its start-up initiatives and consolidation process were complemented with the simultaneous establishment of SPEE international links. In 2010-11 international workshops were run with the support of University of Porto (UPorto) and FEUP. Later on, in 2011, SPEE joined the International Society for Engineering Education (IGIP) and together both societies organized the SPEE-IGIP Flash Moment within the 1st World Engineering Education Flash Week. SPEE has participated in other initiatives, such as CISTI 2011 (Chaves, Portugal), ICECE 2011 (Guimarães, Portugal), Educa Berlin 2011 (collaborating with the IGIP and SEFI workshop “The Role of Pedagogy in Online Engineering Education”), and has also organized Special Tracks in CLME 2011 (Maputo, Mozambique) and in the 41st International Conference of IGIP (Villach, Austria). Here, SPEE organized a Special Track entitled “Talking about Teaching 2012 (TaT’12)”. In the Special Track Session TaT’12 within IGIP2012, SPEE intended to contribute to promote the discussion on Engineering Education (EE) by providing an opportunity for debating and sharing approaches, developments and experiences, in line with the mission of both SPEE and IGIP. “Talking about Teaching” is the name of a thought-provoking column of Susan Zvacek, from Fort Hays State University, in the SPEE Newsletter and it was planned to give continuity to her reflections and to potentiate them within TaT’12 and in future TaT’xx. The proposed topics were concerned not only with resources in EE and with the constant demand on the use of technology, but also with the effectiveness of knowledge in order to guaranty simultaneously the spirit of engineering leadership in society and the lifelong learning capability. They also included the perspective of EE oriented for STEM teachers and students, as well as the sharing of resources with developing countries. The TaT’12 Special Track has been organized in 3 sessions. Each session had an invited speaker, regular presentations and a final group discussion on all its topics. Susan Zvacek engaged all the participants with the topic “Visualizing Understanding with Concept Maps” which motivated some interactivity. James Uhomoibhi discussed “Collaboration and Resource Sharing in Engineering Education”, stressing the importance of the interaction with developing countries and Teresa Larkin spoke about “Authentic Assessment using a Research Conference Format”, showing how complementary and more effective methods can be used to supplement traditional paper and pencil examinations

Partilha e divulgação de experimentação online em cursos de engenharia, suportada por redes de sensores e atuadores sem fios e por conteúdos multimédia

O projeto ―Partilha e divulgação de experimentação online em cursos de engenharia, suportada por redes de sensores e atuadores sem fios e por conteúdos multimédia‖ resultou da candidatura aos Projetos de Partilha e Divulgação de Experiências com Inovação Didática, em 2014, da Fundação para a Ciência e a Tecnologia (FCT). O seu objetivo principal foi a partilha e a divulgação junto de outras instituições de ensino superior, universitárias e politécnicas, de experiências letivas e recursos didáticos, suportados, fundamentalmente, por experimentação online, e desenvolvidos em alguns departamentos da FCTUC e da FEUP no campo da inovação didática, com base na experiência e no conhecimento resultantes de vários projetos anteriores. Do projeto resultaram algumas atividades de partilha de recursos didáticos que demostram a relevância deste tipo de iniciativas.The project "Sharing and dissemination of online experimentation in engineering courses, supported by wireless sensor and actuator networks and by multimedia contents" resulted from the application for Projects of Sharing and Dissemination of Experiences of Teaching Innovation, in 2014, of the Foundation for Science and Technology (FCT). Its main objective was to share and disseminate with other higher education institutions, universities and polytechnics, teaching experiences and educational resources, supported mainly by online experimentation, and developed in some departments of FCTUC and FEUP in the field of didactic innovation, based on the experience and knowledge resulting from several previous projects. The project resulted in some sharing activities of educational resources that demonstrate the relevance of such initiatives.Projetos de Partilha e Divulgação de Experiências com Inovação Didática, em 2014, da Fundação para a Ciência e a Tecnologia (FCT)

Talking about Teaching 2012

The Portuguese Society for Engineering Education (SPEE) was publically launched in 2010. Its start-up initiatives and consolidation process were complemented with the simultaneous establishment of SPEE international links. In 2010-11 international workshops were run with the support of University of Porto (UPorto) and FEUP. Later on, in 2011, SPEE joined the International Society for Engineering Education (IGIP) and together both societies organized the SPEE-IGIP Flash Moment within the 1st World Engineering Education Flash Week. SPEE has participated in other initiatives, such as CISTI 2011 (Chaves, Portugal), ICECE 2011 (Guimarães, Portugal), Educa Berlin 2011 (collaborating with the IGIP and SEFI workshop â??The Role of Pedagogy in Online Engineering Educationâ?), and has also organized Special Tracks in CLME 2011 (Maputo, Mozambique) and in the 41st International Conference of IGIP (Villach, Austria). Here, SPEE organized a Special Track entitled â??Talking about Teaching 2012 (TaTâ??12)â?. In the Special Track Session TaTâ??12 within IGIP2012, SPEE intended to contribute to promote the discussion on Engineering Education (EE) by providing an opportunity for debating and sharing approaches, developments and experiences, in line with the mission of both SPEE and IGIP. â??Talking about Teachingâ? is the name of a thought-provoking column of Susan Zvacek, from Fort Hays State University, in the SPEE Newsletter and it was planned to give continuity to her reflections and to potentiate them within TaTâ??12 and in future TaTâ??xx. The proposed topics were concerned not only with resources in EE and with the constant demand on the use of technology, but also with the effectiveness of knowledge in order to guaranty simultaneously the spirit of engineering leadership in society and the lifelong learning capability. They also included the perspective of EE oriented for STEM teachers and students, as well as the sharing of resources with developing countries. The TaTâ??12 Special Track has been organized in 3 sessions. Each session had an invited speaker, regular presentations and a final group discussion on all its topics. Susan Zvacek engaged all the participants with the topic â??Visualizing Understanding with Concept Mapsâ? which motivated some interactivity. James Uhomoibhi discussed â??Collaboration and Resource Sharing in Engineering Educationâ?, stressing the importance of the interaction with developing countries and Teresa Larkin spoke about â??Authentic Assessment using a Research Conference Formatâ?, showing how complementary and more effective methods can be used to supplement traditional paper and pencil examinations

An Experimental Design Methodology to Evaluate the Key Parameters on Dispersion of Carbon Nanotubes Applied in Soil Stabilization

The incorporation of carbon nanotubes (CNTs) in the process of chemical stabilization of soft soil is only possible when they are dispersed adequately in the medium. The maximum compressive strength (qu max) and the secant undrained Young’s modulus (Eu 50) are usually used to characterize the behavior of soil stabilized with Portland cement. In the present study, soft soil was additivated with a CNT dispersion prepared in a surfactant solution. This information was then used to produce a model based on an experimental design strategy, which allowed us to relate qu max and Eu 50 with the CNT concentration and the surfactant hydrodynamic diameter and concentration. The Partial Least Squares (PLS) regression method was selected to perform the regression, given the significant collinearity among the input variables. The results obtained lead us to conclude that the CNT concentration is the most important factor and has a positive impact on the responses (qu max and Eu 50). The surfactant concentration and hydrodynamic diameter have a negative impact on the responses, but, curiously, when combined, the impact becomes positive. It means that these variables depend on each other. The results obtained show that it is possible to produce a statistical model for these parameters with good correlation coefficient (R2)