ESTiG - Artigos em Revistas Não Indexados à WoS/Scopus
URI permanente para esta coleção:
Navegar
Entradas recentes
- Industrial effluent remediation using aquatic mosses: an effective biosorption approachPublication . Martins, RamiroHeavy metals in industrial wastewater pose significant environmental and public health threats. This study explored the use of the aquatic moss Fontinalis antipyretica as a natural biosorbent to eliminate cadmium (Cd²⁺) and lead (Pb²⁺) from simulated wastewater. The study assessed the impact of crucial factors such as initial pH, contact time, and metal ion concentration, utilizing a sorbent dose of 2 g L⁻¹. Optimal biosorption occurred at pH levels ranging from 4.0 to 6.0, achieving a maximum uptake capacity of 4.8 mg g⁻¹ for both metals at an initial 10 mg L⁻¹ concentration. At a concentration of 100 mg L⁻¹, the removal efficiency of Pb²⁺ exceeded 78%, demonstrating a stronger affinity for Pb. Among the kinetic models tested, the pseudo-second-order model best fit the experimental data (R² = 0.999), indicating that chemisorption was a key mechanism in the process. These results highlight the potential of Fontinalis antipyretica as an effective, cost-efficient, and environment-friendly method for treating metal-laden industrial effluents
- Chlorine reactivity with organic matter: a modelling approach for surface waters in Portugal and AngolaPublication . Martins, RamiroWater quality is an essential requirement for human consumption. One of the key quality criteria is the absence of bacterial contamination, necessitating disinfection as the final step in water treatment, which is commonly achieved through chlorination. During chlorination, chlorine is consumed through the oxidation of the organic compounds present in water. This study focused on examining chlorine consumption in raw water from the Bengo River (Angola) and water at the outlet of the Lever Water Treatment Plant (Portugal). Specifically, the decay kinetics of chlorine in water samples were investigated through a series of experiments. In the first series, the chlorine concentration was varied while maintaining a constant level of organic matter (expressed as oxidability using KMnO4) at temperatures of 25 and 35°C. In the second series, the chlorine concentration was held constant while the oxidability varied. Various kinetic models have been applied to the experimental data to describe the decay of chlorine and organic matter. The parallel first-order model yielded the most satisfactory representation of chlorine consumption kinetics.
- Assessing surface water contamination by toxic metals via bioindicators: public health implicationsPublication . Martins, RamiroThis study presents the results of heavy metal concentrations in aquatic mosses collected from the Ave River Basin during two field surveys (campaigns II and III) and a comparison with data from a field survey carried out 15 years earlier (campaign I). The findings indicated high levels of chromium in the samples from the two previous campaigns, along with aggravated contamination of cadmium, lead, and zinc compared to campaign I. The order of metal accumulation in the moss samples, from highest to lowest, was Fe > Zn > Cu > Cr > Ni > Pb > Cd > Hg. The Metal Pollution Index (MPI) revealed changes in contamination levels between campaigns. Most stations experienced a decrease in classification due to increased water flow and reduced accumulation during Campaign II. The contamination patterns suggest the influence of industrial activities, particularly metal coating facilities. Monitoring and mitigation efforts are necessary to address persistent heavy metal pollution in the Ave River Basin.
- Using bioindicators to assess heavy metal contamination in surface waters and public health impactsPublication . Martins, RamiroThis study aims to explore the use of bioindicators for assessing metal contamination in surface waters and its effects on public health. Theoretical Framework: The persistence and variation of heavy metal contamination in the Ave River Basin over 15 years underscore the need for ongoing monitoring and intervention. The detection of elevated levels of chromium, cadmium, lead, and zinc in aquatic mosses highlights the continuing impact of industrial activities, particularly metal coating facilities, on the river's ecosystem. Method: In the study area, the Ave River and some of its tributaries, a monitoring programme of twelve sampling points was defined in two campaigns and eight metallic ions were determined in the laboratory by atomic absorption spectrophotometry (Cd, Pb, Cu, Cr, Fe, Hg, Ni and Zn). Results and Discussion: The highest metal accumulation in mosses was observed for iron (Fe), whereas the lowest accumulation was found for mercury (Hg) during Campaign II. The order of metal accumulation in the moss samples, from highest to lowest, was Fe > Zn > Cu > Cr > Ni > Pb > Cd > Hg. The Metal Pollution Index (MPI) revealed changes in contamination levels between campaigns. Research Implications: The contamination patterns suggest the influence of industrial activities, particularly metal coating facilities. Monitoring and mitigation efforts are necessary to address persistent heavy metal pollution in the Ave River Basin. Originality/Value: The results of this research will contribute to a better understanding of the sources and loads of pollutants discharged and responsible for the contaminants. This can be used to discourage potential polluters and better manage the basin's water resources and possible risks to human health.
- Advanced treatment of pomace olive oil wastewater through peroxy-electrocoagulationPublication . Martins, Ramiro; Grabowski, TaisThe extraction of olive pomace oil is a significant aspect of the Mediterranean edible oil industry; however, the wastewater generated contains pollutants that can harm the environment and public health. In this study, peroxi-electrocoagulation (PEC) with aluminum electrodes was used to treat wastewater and reduce pollutant concentrations. A Box-Behnken Design study was conducted to investigate the relationship between hydrogen peroxide dosage, electric current density, and initial pH in the PEC process, and the removal of chemical oxygen demand (COD) and total phenolic compounds (TPh). The study found that the PEC process could remove an average of 22% of COD and 82% of TPh, with the highest removal obtained with hydrogen peroxide dosages of 30 g L -1 and 20 mA cm -2. However, pre-treatment with other processes is necessary to reduce harmful elements in the effluent before undergoing biological treatment.
- Green solutions for industrial effluent treatment: he role of aquatic mossesPublication . Martins, RamiroIn the present study, the performance of the aquatic moss Fontinalis antipyretica for removing cadmium and lead from simulated wastewaters has been evaluated. Five kinetic models were fitted to the experimental data and compared. Previously, the effect of parameters such as the initial solution pH, contact time, and initial metal ion concentration on biosorption was investigated using a sorbent dose of 2 g l-1. The initial pH of the solution was found to have an optimum value in the range of 4.0-6.0. The equilibrium sorption capacity of cadmium and lead by Fontinalis antipyretica increased with the initial metal concentration. For an initial metal concentration of 10 mg l -1, the uptake capacity of the moss, at equilibrium, is the same for both metals (4.8 mg g -1). Nevertheless, when the initial concentration increases up to 100 mg l-1, the uptake of Pb(II) is higher than 78%. The pseudo-second order biosorption kinetics provided the better correlation with the experimental data (R 2 0.999).
- Enhancing energy recovery from raw glycerol via ultrasound-assisted anaerobic digestionPublication . Martins, RamiroAnaerobic digestion of crude glycerol derived from biodiesel production is being studied as an alternative to valorization through methane production. The high organic load (1800 g COD L -1) of crude glycerol can cause kinetic stress, leading to inhibition of methanogenic microorganisms. To overcome this issue, an alternative approach is the use of ultrasound energy, which promotes cell wall and membrane disruption and releases intracellular material that enhances biodigestion. Considering this alternative, the main objective of this study was to test ultrasound pretreatment to facilitate the subsequent anaerobic digestion of crude glycerol
- Bioindicators for assessing heavy metal contamination in surface waters and public healthPublication . Martins, RamiroThis study presents the results of heavy metal concentrations in aquatic mosses collected from the Ave River Basin during two field surveys (campaigns II and III) and a comparison with data from a field survey carried out 15 years earlier (campaign I). The findings indicated high levels of chromium in the samples from the two previous campaigns, along with aggravated contamination of cadmium, lead, and zinc compared to campaign I. The order of metal accumulation in the moss samples, from highest to lowest, was Fe > Zn > Cu > Cr > Ni > Pb > Cd > Hg. The Metal Pollution Index (MPI) revealed changes in contamination levels between campaigns. Most stations experienced a decrease in classification due to increased water flow and reduced accumulation during Campaign II. The contamination patterns suggest the influence of industrial activities, particularly metal coating facilities. Overall, ongoing monitoring and mitigation efforts are necessary to address persistent heavy metal pollution in the Ave River Basin.
- Contributos sobre o pensamento computacional na formação inicial de professores: uma experiência com o Scratch para o 1.º CicloPublication . Branco, Neusa; Barros, Paula MariaO pensamento computacional é assumido como uma competência do século XXI, ganhando reflexo nas revisões curriculares dos últimos anos em diversos países. Em Portugal, o pensamento computacional surge como uma das capacidades matemáticas transversais nas Aprendizagens Essenciais de Matemática de 2021. Este artigo apresenta um estudo de natureza exploratória que visa conhecer o contributo do trabalho de futuras professoras dos primeiros anos com o Scratch para a sua prática futura no 1.º ciclo do ensino básico, num contexto de formação que integra a aprendizagem da Geometria e Medida e o desenvolvimento do pensamento computacional. Participam no estudo quatro futuras professoras que frequentam mestrados que habilitam para a docência no 1.º ciclo do ensino básico. Os resultados evidenciam o reconhecimento das futuras professoras de oportunidades de integração do conhecimento matemático e de práticas do pensamento computacional com a realização e discussão da tarefa “A horta da turma”, de desafios na gestão da aula e de dificuldades dos alunos, que conseguem antecipar. A realização dessa tarefa com recurso ao Scratch permite identificar a articulação entre práticas do pensamento computacional e a aprendizagem de tópicos matemáticos específicos, como sendo o perímetro e a área de retângulos.
- Realização de estudantes do ensino superior na exploração de um jogo aleatórioFernandes, José António; Gonçalves, Gabriela; Barros, Paula MariaNeste artigo estuda-se a realização de estudantes do ensino superior politécnico na exploração de um jogo aleatório, tendo em conta os seguintes objetivos: 1) avaliar o desempenho dos estudantes na exploração do jogo; e 2) identificar dificuldades dos estudantes na exploração do jogo. Participaram no estudo 49 estudantes que se encontravam a frequentar o 2º ou o 3º ano de um curso de engenharia de uma instituição de ensino superior do norte de Portugal. Os dados resultaram das resoluções dos estudantes a várias tarefas sobre jogos aleatórios de um breve questionário, sendo aqui estudada apenas uma dessas tarefas. Dos resultados obtidos, salienta-se uma realização não satisfatória dos estudantes na exploração do jogo, o que se manifestou em várias dificuldades dos estudantes, designadamente, ao não explicarem a origem dos valores que apresentaram, ao determinarem probabilidades incorretas e ao cometerem outros erros, como sejam erros de cálculo e de interpretação daquilo que era pedido. Assim, face aos resultados insatisfatórios do estudo, torna-se importante aprofundar a formação dos estudantes acerca da definição, interpretação e aplicação da noção de jogo aleatório. Para tal, a exploração de jogos aleatórios na sala de aula pode contribuir para a melhoria da realização dos estudantes, já que eles raramente são aí explorados.