63 research outputs found

    Developing a Compost Quality Index (CQI) based on the electrochemical quantification of Cd (HA) reactivity

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    The present work demonstrates the use of Cd2+ as a reactivity probe of the fulvic acids (FAs), humic acids (HAs) and dissolved organic matter (DOM) compost extracts. Significant differences were observed between the extracts, with the HA extract showing the highest reactivity. Comparing the different composts, the largest reactivity variation was again observed for HA then FA and finally DOM extracts. The Cd2+ binding extent was used to calculate the quality of composts and compared with a reference of uncomposted organic fertiliser (FLW), leading to the definition of an operational scale of compost quality. The parameter equivalent mass of fertiliser (mEF) was used for this scale sorted the seven composts from 0.353 to 1.09 kg FLW, for compost of sewage sludge (CSS) and vermicompost of domestic waste (CVDW), respectively. The significance of this parameter was verified through a correlation analysis between binding extent and the effect of compost application on lettuce crop growth in a field trial. The results demonstrate the potentiality of FA and HA extracts as markers of compost bioactivity and the use of Cd2+ as a reactivity probe.This work was financially supported by the Interreg VA Spain‚ÄďPortugal Programme (EU) through the project Res2ValHum (0366_RES2VALHUM_1_P). A.C. Silva acknowledges receipt of a PhD grant (UMINHO/BD/40/2016) financed by the Operational Programme Norte 2020 (through the Project ‚ÄúNORTE-08-5369-FSE-000033‚ÄĚ). J. Antelo and S. Fiol are also grateful for the financial support provided by Xunta de Galicia‚ÄĒConseller√≠a de Educaci√≥n e Ordenaci√≥n Universitaria de Galicia (Consolidation of Competitive Groups of Research; GI-1245, ED431C 2022/40)

    Global Women’s Breakfast (GWB): #UnidaspelaQuímica

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    Global Women‚Äôs Breakfast (GWB): #BoundbyChemistry. Global Women‚Äôs Breakfast is an initiative of the International Union of Pure and Applied Chemistry, aiming to give women scientists, from all over the world, the opportunity to know each other, communicating virtually and sharing their experiences. Many countries joined this initiative and Portugal was not an exception, with its participation already at the first Networking Breakfast in 2011, celebrating the year of the centenaries of Marie Curie Nobel Prize in Chemistry, the Portuguese Chemical Society and the Faculdade de Ci√™ncias da Universidade de Lisboa as well. The success of these networking breakfasts, involving students, young researchers, and scientists, encouraged its further organization in Portugal, annually since 2019. This article describes the interventions of Portuguese women scientists, coming from Institutions throughout Portugal, in the Global Women‚Äôs Breakfast as partners in their mission as scientists, creative and open to international collaborations. Global Women's Breakfast √© uma iniciativa criada pela International Union of Pure and Applied Chemistry para dar oportunidade √†s mulheres cientistas de todo o mundo de se conhecerem, comunicando virtualmente e compartilhando as suas experi√™ncias. A ades√£o dos pa√≠ses foi muito elevada e Portugal n√£o foi exce√ß√£o, participando j√° no primeiro Networking Breakfast em 2011, Ano Internacional da Qu√≠mica, no qual se celebraram os centen√°rios do Pr√©mio Nobel da Qu√≠mica a Marie Curie, da Sociedade Portuguesa de Qu√≠mica e da Faculdade de Ci√™ncias da Universidade de Lisboa. O sucesso destes pequenos-almo√ßos em rede, que envolvem estudantes, jovens investigadoras e cientistas, encorajou a continua√ß√£o da participa√ß√£o de Portugal anualmente, desde 2019. Este artigo descreve a interven√ß√£o de mulheres cientistas portuguesas, pertencentes a institui√ß√Ķes de Norte a Sul do pa√≠s, no Global Women‚Äôs Breakfast, c√ļmplices na sua miss√£o de cientistas, criativas e abertas √† colabora√ß√£o internacional

    Avaliação da capacidade de composto produzido industrialmente para remoção de paracetamol de águas

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    O composto √© um material produzido pela decomposi√ß√£o de mat√©ria org√Ęnica atrav√©s de um processo denominado de compostagem. Neste processo ocorre uma estabiliza√ß√£o da mat√©ria org√Ęnica, com forma√ß√£o de mol√©culas ricas em estruturas arom√°ticas contendo grupos hidroxilo e carbonilo [1]. Estas estruturas qu√≠micas, usualmente classificadas de subst√Ęncias h√ļmicas, oferecem um enorme potencial para estabelecer intera√ß√Ķes intermoleculares. Esta potencialidade √© altamente desej√°vel, permitindo a sua utiliza√ß√£o na constru√ß√£o de filtros para o tratamento terci√°rio de √°guas residuais [2]. O paracetamol √© um composto ativo amplamente utilizado como f√°rmaco¬†possuindo propriedades analg√©sicas e antipir√©ticas, sendo¬†a sua administra√ß√£o feita em humanos ou animais, e posteriormente libertados no meio ambiente por v√°rias vias. A ocorr√™ncia deste f√°rmaco e seus metabolitos nas √°guas residuais √© descrita como uma preocupa√ß√£o crescente, sendo nocivos para os organismos aqu√°ticos e podendo mesmo apresentar riscos para a sa√ļde humana [3]. Inserido no √Ęmbito do projeto Res2ValHum [4], foi efetuado um estudo preliminar em¬†batch¬†onde se testou a remo√ß√£o de paracetamol utilizando composto produzido industrialmente em t√ļnel, a partir de res√≠duos urbanos provenientes de recolha seletiva. As solu√ß√Ķes de paracetamol usadas tinham concentra√ß√Ķes compreendidas entre 20 e 375 mg L-1¬†(C0) e as massas de composto testadas foram entre 0,5 e 4,5 g (mcomposto). Os ensaios foram realizados ao longo do tempo e monitorizados recorrendo a HPLC - DAD. Foi estudada a influ√™ncia de par√Ęmetros, como a concentra√ß√£o inicial de f√°rmaco, a massa de composto, o pH e a presen√ßa de surfactantes (presentes em √°guas residuais,¬†?√°guas cinzentas?). Verificou-se que a percentagem de remo√ß√£o depende da massa de composto e da concentra√ß√£o inicial de paracetamol. Os resultados reportados na¬†Figura 1¬†foram calculados a partir das concentra√ß√Ķes de paracetamol em solu√ß√£o medidas para um tempo de 60 min, Ceq¬†(Concentra√ß√£o de equil√≠brio). ¬†Programa Interreg V-A Espanha-Portugal (POCTEP) 2014-2020 e a Uni√£o Europeia atrav√©s do Fundo Europeu de Desenvolvimento Regional -FEDER no √Ęmbito do projeto RES2VALHUM -Valoriza√ß√£o de Res√≠duos Org√Ęnicos: Produ√ß√£o de Subst√Ęncias H√ļmicas (0366_RES2VALHUM_1_P

    Characterization of organic matter at different stages of a composting process

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    The characterization of the organic matter from raw organic wastes, unmatured compost and maturated compost was performed by different techniques: gravimetric, FTIR-ATR, TGA and from the ability of their extracts to bind Cd2+ (evaluating the free cadmium ion by AGNES). Although the amount of humic-like and fulvic-like acids did not change significantly, the structure and properties of the organic matter changed with composting and maturation. These changes resulted in an increase of the stability of the organic material toward thermal decomposition and in an increase of the capacity to bind cadmium.0366_RES2VALHUM_1_P - Valoriza√ß√£o de res√≠duos org√Ęnicos: produ√ß√£o de subst√Ęncias h√ļmicas, cofinanciada pelo Fundo Europeu de Desenvolvimento regional (FEDER) atrav√©s do Programa INTERREG V-A Espanha-Portugal (POCTEP) 2014-2020

    Comparison of cadmium binding by humic and fulvic acids extracted from two composts of different origin

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    Composting has been proven to be an environmentally friendly process for urban organic waste, that can represent an opportunity for new uses under the circular economy framework. The binding of cadmium to fulvic-like and humic-like acids extracted from compost of algae and urban residues were evaluated, and the results show significant differences. The fulvic and humic acids from algae compost bind cadmium more efficiently than those from urban residues compost. Furthermore, data from humic acids from both composts display significantly higher ability to bind to cadmium than both their corresponding fulvic acids and the generic soil extracted humic matter. ¬†Cooperation Program Interreg V-A Spain-Portugal (POCTEP) 2014-2020 and the European Union through the European Regional Development Fund -FEDER within the scope of the project ¬ęRES2VALHUM -Valorization of Organic Waste: Production of Humic Substances¬Ľ (0366_RES2VALHUM_1_P).The authors want to thank LIPOR for the supply of COUR sample. Members of the USC are also grateful to CRETUS Strategic Partnership (ED431E 2018/01) co-funded by FEDER and the Galician Competitive Research Group GRC ED431C/12.Members of the Department of Chemistry are also grateful toCenter of Chemistrythrough projects UID/QUI/00686/2016 and UID/QUI/00686/2019 (CQUM) funded by Foundation for Science and Technology (FCT, Portugal

    Comparison of cadmium binding by humic and fulvic acids extracted from compost samples of different feedstock

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    Compost is a bio-sustainable material produced by the controlled decomposition of the organic wastes. Composting can be employed for the urban organic waste treatment in alternative to incineration or landfill disposal [1]. The properties of compost are closely related to the presence of humic-like substances (HS). Both fulvic acids (FA) and humic acids (HA) contain a significant amount of carboxylic acids and phenolic groups that are responsible for some of their properties like solubility and ability to complex metal ions [2]. In the scope of the project Res2ValHum [3], composts produced from different feedstock were analysed and compared regarding the ability of the FA and the HA extracts to bind Cd2+. The free cadmium ion concentration was measured using the electroanalytical technique AGNES (absence of gradients and Nernstian equilibrium stripping) [4]. The cadmium binding by FA and HA extracts of two compost samples: compost of algae (CA) and compost of sludge sewage (CSS) is illustrated in Figure 1. Results indicate that the extent of the binding of cadmium by FA is similar despite the nature of the compost. In opposition, the HA extracts from the algae compost exhibit a larger capacity to bind cadmium ion in comparison to the extracted from the sludge sewage compost. These results indicate that the nature of the feedstock seem to affect more the structure of the HA (in comparison to the FA) formed during the composting process. The chemical characterization of these extracts by different analytical techniques are in course in order to fully understand the referred effect.0366_RES2VALHUM_1_P - Valoriza√ß√£o de res√≠duos org√Ęnicos: produ√ß√£o de subst√Ęncias h√ļmicas, cofinanciada pelo Fundo Europeu de Desenvolvimento regional (FEDER) atrav√©s do Programa INTERREG V-A Espanha-Portugal (POCTEP) 2014-202

    Evaluation of total polyphenol content of wines by means of voltammetric techniques: Cyclic voltammetry vs differential pulse voltammetry

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    Taking advantage of the low oxidation potential of polyphenolic compounds, voltammetric techniques, such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are used rather indiscriminately. In this work, we report Total Polyphenols results (TPP) obtained by these two techniques from a set of nine samples of red and Tawny Port wine. The CV and DPV voltammograms display significant correlations with the physical-chemical parameters used to characterize red and Tawny Port wines, particularly with polyphenols. Although data obtained from CV and DPV for a single polyphenol are directly proportional, important deviations are found between voltammetric results from wines. Results from CV tend to be larger than those from DPV. This difference, that can reach 50% of the TPP value, was related to the presence of total sulphur dioxide. In view of the present study, the polyphenol quantification in wines should be performed by DPV to minimize the interference of SO2.This work received financial support from the Foundation for Science and Technology (FCT, Portugal), through projects UID/QUI/00686/2013 and UID/QUI/00686/2016 (CQUM)

    Let there be light...

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    ‚ÄúLet there be light...‚ÄĚ is a project in the scope of the International Year of Light 2015 (IYL 2015) targeted at children of the first school grade. Basically, it comprises nine recreational - scientific workshops that last for approximately 90 minutes. Each workshop is dedicated to a different topic, namely: bioluminescence, mineral observation, the rainbow, light-shadow contrast, battery production, just to name a few, and is designed, in differ- ent approaches, by a distinct team of scientists familiar to the scientific area focused. The activity starts with the dramatized storytelling of a children‚Äôs story related to the scientific subject and performed by the team of the public library expert in this area. This moment takes place in an almost magical environment opening the door to the science topic light-related that would be focused later on. In the third part of the workshop, the children are invited to produce plastic works (e.g. drawings, constructions and models) inspired in what they have learned, and that are to be collected in a public exhibition held at the same institution at the end of the project. In the present work, besides the description of the experience, you can find the critical analysis of the activity and the evaluation of the action by all the actors involved (project team and children/teachers that attended the workshops).info:eu-repo/semantics/publishedVersio

    Probing the surface of oxidized carbon nanotubes by selective interaction with target molecules

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    Screen printed carbon electrodes (SPCE) were modified with pristine and oxidized carbon nanotubes (CNTprist and CNTox, respectively). The extent of CNT oxidation evaluated by TGA increasedwith the time of reflux in nitric acid. The CNTox surface coverage by quinoid/phenolic functional groupswas quantified by their voltammetric response at low redox potentials. Cyclic voltammetry was performed with SPCE-CNTox on solutions of hydroquinone, dopamine and ferricyanide used as model compounds. The sensitivity of reduced/oxidized forms of these molecules to the oxygen-containing functional groups of the CNTox was evaluated by the current intensity. Compoundswith phenol/amine groups showa large increase of the current intensity with increasing CNT oxidation, while for carbonyl containing compounds only a negligible effect was perceived. Molecules that can hydrogen bond to the CNT functional groups interact better with the electrode surface, and this is supported by theoretical calculations. This showcases the use of CNTox modified SPCE for selective sensing.PEst-C/QUI/UI0686/2013 (Research Centre CQ/UM), project UID/CEC/00319/2013 (Centro ALGORITMI), and project PEst-C/CTM/LA0025/2013 (IPC/I3N

    Let there be light...

    No full text
    “Let there be light..." is a project in the scope of the International Year of Light 2015 (IYL 2015) targeted at children of the first school grade. Basically, it comprises nine recreational - scientific workshops that last for approximately 90 minutes. Each workshop is dedicated to a different topic, namely: bioluminescence, mineral observation, the rainbow, light-shadow contrast, battery production, just to name a few, and is designed, in different approaches, by a distinct team of scientists familiar to the scientific area focused. The activity starts with the dramatized storytelling of a children’s story related to the scientific subject and performed by the team of the public library expert in this area. This moment takes place in an almost magical environment opening the door to the science topic light-related that would be focused later on. In the third part of the workshop, the children are invited to produce plastic works (e.g. drawings, constructions and models) inspired in what they have learned, and that are to be collected in a public exhibition held at the same institution at the end of the project. In the present work, besides the description of the experience, you can find the critical analysis of the activity and the evaluation of the action by all the actors involved (project team and children/teachers that attended the workshops).info:eu-repo/semantics/publishedVersio
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