The influence of structure and surface chemistry of carbon materials on the decomposition of hydrogen peroxide

Carbon materials with different structural and chemical properties, namely activated carbons, carbon xerogels, carbon nanotubes, graphene oxide, graphite and glycerol-based carbon materials, were tested under different operating conditions for their ability to catalyse hydrogen peroxide (H2O2) decomposition in aqueous solutions. Activated carbons treated with concentrated sulphuric acid (ACS) are the most active catalytic materials for H2O2 decomposition in most of the conditions studied, due to the presence of sulphur containing functional groups at their surface. In addition, ACS proved to be a stable catalyst in reutilization tests for H2O2 decomposition. Methanol was used as selective scavenger of hydroxyl radicals (HO center dot), to show that activated carbons with a markedly basic character lead to the highest yield of HO center dot formed during the H2O2 decomposition process (14%, after 150 min of reaction). Overall, from the mechanistic interpretation of H2O2 decomposition, it is concluded that the presence of sulphur containing functional groups at the surface of the activated carbons improves the removal of H2O2 in aqueous solutions, but, on the other hand, the selective decomposition of H2O2 via HO center dot formation is enhanced by the presence of basic active sites on the Carbon surface

Enhanced performance of cobalt ferrite encapsulated in graphitic shell by means of AC magnetically activated catalytic wet peroxide oxidation of 4-nitrophenol

Here we report preliminary catalytic wet peroxide oxidation (CWPO) experiments performed in the presence of an alternating current (AC) magnetic field. One ferromagnetic graphitic nanocomposite - composed by a cobalt ferrite core and a graphitic shell (CoFe2O4/MGNC), was employed in the process, here named magnetically activated catalytic wet peroxide oxidation (MA-CWPO). An aqueous solution containing 5.0 g L-1 of 4-nitrophenol (4-NP) to simulate a high strength polluted stream was used as model system. The experiments were performed at room temperature and atmospheric pressure, with stoichiometric amount of hydrogen peroxide (H2O2), pH = 3 and CoFe2O4/MGNC catalyst load = 5.0 g L-1 (corresponding to a 4-NP/CoFe2O4 mass ratio of 6.9, as CoFe2O4 accounts for 14.4 wt% of CoFe2O4/MGNC). It was shown that the performance of CWPO is enhanced upon application of an AC magnetic field (frequency of 533.9 kHz and magnitude of 240 G). As a result, high 4-NP mineralization was obtained by MA-CWPO (as reflected by a total organic carbon abatement of 79% after 4 h of reaction, instead of 39% in the absence of a magnetic field). This positive effect was ascribed to the localised increase of CoFe2O4/MGNC surface temperature resulting from heat release upon exposure of the nanoparticulated catalyst to an AC magnetic field, which accelerates the catalytic decomposition of H2O2 via hydroxyl radicals (HO center dot) formation

Geomorfologia e morfotectónica de relevos quartzíticos: a megaestructura de Caldas de S. Jorge - Águeda, NW de Portugal

RESUMO. Este trabalho tem como objectivo a apresentação de uma síntese geomorfológica e morfotectónica regional dos relevos quartzíticos do domínio estrutural de Caldas de S. Jorge–Águeda (Maciço Ibérico, NW de Portugal). Estes relevos configuram dois importantes alinhamentos topográficos, descontínuos, com orientação geral meridiana, constituídos por rochas de idade paleozóica inferior. A expressão morfoestrutural dos ramos quartzíticos está intimamente relacionada com a faixa de cisalhamento de Porto–Coimbra–Tomar. Os levantamentos de campo efectuados permitiram reconhecer e cartografar, pela primeira vez, novos afloramentos quartzíticos do Ordovícico, a Norte de Águeda, onde se encontram relevos associados a escarpas de falhas ao longo de antigas zonas de falhas regionais. Desse modo, obteve-se informação inédita e vital para um melhor entendimento do complexo limite geotectónico da faixa de cisalhamento de Porto–Coimbra–Tomar. This study aims at presenting a geomorphological and morphotectonical characterisation of the quartzite relief of the Caldas de S. Jorge–Águeda structural domain (Iberian Massif, NW Portugal). These quartzite outcrops take the form of a narrow NNW-SSE strip of early Palaeozoic age, which is included in a major crustal-scale strike-slip zone, the so-called Porto–Coimbra–Tomar shear zone. The geomorphologic and geotectonical surveys led us to newly describe and mapping the Ordovician quartzite relief structure to the North of Águeda town, and show that the large-scale relief is strongly associated with the existence of scarps along inherited regional fault zones. These results suggest that relief development in this region was mainly controlled by tectonics through fault reactivation

Polymer microfluidic devices: an overview of fabrication methods

The amount of applications associated with microfluidic devices is increasing since the introduction of Lab-on-a-chip devices in the 1990s, especially regarding biomedical and clinical fields. However, in order for this technology to leave the fundamental research and become a day-life technology (e.g., as point-of-care testing), it needs to be disposable and reasonably less expensive. Polymers, due to their several advantages, such as easier microfabrication and low-cost, fill these needs. Several methods are reported regarding microfabrication and, thus, the main aim of the present work is to provide an overview of the most relevant microfabrication techniques found in literature employing polymers, clarifying also the main advantages and disadvantages of each technique and especially considering their cost and time-consumption. Moreover, a future outlook of low-cost microfabrication techniques and standard methods is provided

Haemocompatibility of iron oxide nanoparticles synthesized for theranostic applications: a high-sensitivity microfluidic tool

The poor heating efficiency of the most reported magnetic nanoparticles (MNPs), allied to the lack of comprehensive biocompatibility and haemodynamic studies, hampers the spread of multifunctional nanoparticles as the next generation of therapeutic bio-agents in medicine. The present work reports the synthesis and characterization, with special focus on biological/toxicological compatibility, of superparamagnetic nanoparticles with diameter around 18 nm, suitable for theranostic applications (i.e. simultaneous diagnosis and therapy of cancer). Envisioning more insights into the complex nanoparticle-red blood cells (RBCs) membrane interaction, the deformability of the human RBCs in contact with magnetic nanoparticles (MNPs) was assessed for the first time with a microfluidic extensional approach, and used as an indicator of haematological disorders in comparison with a conventional haematological test, i.e. the haemolysis analysis. Microfluidic results highlight the potential of this microfluidic tool over traditional haemolysis analysis, by detecting small increments in the rigidity of the blood cells, when traditional haemotoxicology analysis showed no significant alteration (haemolysis rates lower than 2 %). The detected rigidity has been predicted to be due to the wrapping of small MNPs by the bilayer membrane of the RBCs, which is directly related to MNPs size, shape and composition. The proposed microfluidic tool adds a new dimension into the field of nanomedicine, allowing to be applied as a highsensitivity technique capable of bringing a better understanding of the biological impact of nanoparticles developed for clinical applications.This work was financially supported by: Project POCI-01-0145-FEDER-006984 – Associate Laboratory J Nanopart Res (2016) 18:194 Page 15 of 17 194 123 LSRE-LCM funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalizac¸a˜o (POCI) – and by national funds through FCT - Fundac¸a˜o para a Cieˆncia e a Tecnologia. R.O.R. acknowledges the Ph.D. scholarship SFRH/BD/97658/2013 Granted by FCT. A.M.T.S acknowledges the FCT Investigator 2013 Programme (IF/01501/ 2013), with financing from the European Social Fund and the Human Potential Operational Programme. M.B. would like to thank ERDF (European Regional Development Fund) under grant PO Norte CCDR-N/ON.2 Programme. J.G. also thanks the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 600375.info:eu-repo/semantics/publishedVersio

High-performance liquid chromatography as a tool to evaluate the performance of the catalytic wet peroxide oxidation of 4-nitrophenol: pre-validation of analytical methods

A high-performance liquid chromatography (HPLC) method capable to detect 4-nitrophenol (4-NP) in aqueous solutions with concentration in the range 0.0495-118.8 mg L-1 was developed and validated under the typical criteria for in -house pre-validations. Accordingly, linearity was demonstrated through the Fisher’s exact probability test. Accuracy and precision were then assessed in three concentrationlevels over the linear range. The reproducibility of the catalytic wet peroxide oxidation (CWPO) of 4-NP was evaluated together with the analytical error of 4-NP determination in independent experiments. In this case, the sum of both contributions to error never reached 3%.Two multi-component HPLC methods were also developed for the determination of possible aromatic intermediates (hydroquinone, 1,4-benzoquinone, catechol, 4-nitrocatechol and phenol) and carboxylic acids (oxalic, formic, malic, malonic, acetic and maleic acids) resulting from the 4-NP degradation. The combination of these analytical methods already led to the proposal of an oxidation/mineralization mechanism for the CWPO of 4-NP

Women's refolution at work

The renowned Age of Revolution encompasses the period between the American Revolution (1776) and the so-called Spring of Nations in 1848, this being the height of the revolutionary movements in Europe in the 19th century, though it may be considered just the tip of the iceberg as far as civil rights movements for people from all walks of life are concerned. The changes that occurred throughout this timespan intended to move from feudal and absolutist systems, considered old-fashioned and ill-suited, to constitutionalist states and republics that would be able to heed the new values, e.g. liberalism, nationalism and socialism, as well as the demands of the working classes, enduring the harmful effects of industrialisation. Working people had been flowing into large industrial cities for over a century since the onset of the Industrial Revolution, leaving behind their home places and settling in overcrowded, rundown dwellings in appalling living conditions. The shift from working at home to working in factories brought along a number of issues that would be the motivation for setting up trade unions, namely the long working hours (between 12 and 14 hours per day), the low wages, the cruel discipline and the fierce system of fines that was applied, and the numerous accidents and health issues that ensued. Despite the overall negative conditions, women and children were among those who suffered the most, especially because the former’s wages were regarded as secondary earnings and thus less important than men’s. Consequently, from 1850s onwards, trade unions began to fight for better paid workers and women were initially excluded from these structures be it as members or leaders, being supported by social reformers instead. As a case in point, it is worth mentioning Clementina Black who, in 1888, set forth a demand for equal pay between men and women in the UK and the Bryant and May match factory strike which was held in the same year. Bearing in mind this social and historical context, our aim with this paper is two-fold: not only do we seek to focus on unionist movements in the last half of the 19th century in the European context as a means to fight against conservative and slavery-like practices in the workplace but we also wish to emphasise the place and importance of working-class women in this general workers’ assertion, particularly in their attempt to gain equal pay, a true refolution that would be the motivational beacon for 20th century movements, such as that of the suffragettes.info:eu-repo/semantics/publishedVersio