Teses de Mestrado ESTiG
URI permanente desta comunidade:
Navegar
Percorrer Teses de Mestrado ESTiG por Objetivos de Desenvolvimento Sustentável (ODS) "06:Água Potável e Saneamento"
A mostrar 1 - 9 de 9
Resultados por página
Opções de ordenação
- Advances in fenton and photo-fenton degradation of anionic surfactant SDBSPublication . Silva, Arthur Mariani; Martins, Artur; Pietrobelli, JulianaSurfactants are widely used in hygiene and cleaning products; however, their persistence in aquatic environments classifies them as emerging contaminants. This study aimed to evaluate the behavior and degradation efficiency of the anionic surfactant Sodium Dodecyl Benzene Sulfonate (SDBS) using Fenton and photo-Fenton Advanced Oxidation Processes (AOPs). Analytical monitoring of pollutant removal was performed using High-Performance Liquid Chromatography (HPLC). To optimize the operational variables – namely reaction time, pH, H2O2 and Fe2+ concentrations – Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) were applied using Jamovi and RStudio software. The experimental results demonstrated that the photo-Fenton process significantly outperformed the conventional Fenton process, which was driven by UV radiation, promoting the continuous regeneration of Fe2+ ions and maximizing the generation of hydroxyl radicals (HO•). The reduced quadratic model for the photo-Fenton system was statistically significant (p = 0.013), highlighting reaction time as a critical factor (p = 0.024) and indicating a strong negative quadratic effect of iron concentration. The 3D response surfaces confirmed the presence of an optimal intermediate operation region, proving that excessive reagent dosages trigger scavenging effects, which limit further removal efficiency. The Fenton process achieved SDBS removal ranging from 22% to 52%, whereas the photo-Fenton process achieved SDBS removal ranging from 50% to 76%, demonstrating that both processes were effective and that UV irradiation enhanced the oxidative efficiency of the system. Ultimately, this study provides a robust technical framework aligned with the United Nations 2030 Agenda, directly contributing to Sustainable Development Goal 6 (Clean Water and Sanitation) by engineering efficient pathways for the removal of persistent surfactants from wastewater, while also aligning with SDG 12 (Responsible Consumption and Production) and SDG 14 (Life Below Water).
- Aproveitamento de águas pluviais em edifícios escolares com coberturas verdes ou convencionais: contributos para uma drenagem urbana sustentávelPublication . Chen, Sanlira Shuting; Silva, Flora; Antão-Geraldes, Ana Maria; Jabur, Andrea SartoriA água é um recurso essencial para a vida e o desenvolvimento sustentável, mas a sua escassez, agravada pelo crescimento populacional, urbanização e mudanças climáticas, representa um desafio global. Soluções como os sistemas de aproveitamento de águas pluviais (SAAP) e as coberturas verdes (CV) emergem como estratégias promissoras promovendo benefícios ambientais, sociais e econômicos. Assim, este estudo avaliou o consumo de água em dois edifícios escolares em Bragança (Portugal), propondo medidas de eficiência hídrica por meio da implementação de SAAP, CV, integração dessas tecnologias e substituição das torneiras existentes por modelos mais eficientes. O Centro Escolar de Santa Maria (CESMaria) consome 2.820,2 m³/ano de água no período com rega, e o Centro Escolar da Sé (CESé), 5.260,5 m³/ano. O Cenário 1 (substituição de torneiras) mostrou-se a opção mais viável a curto prazo, com retorno do investimento em 1 ano, reduzindo o consumo de água em aproximadamente 30% e gerando economias anuais de cerca de 3.700 € + IVA em ambos os edifícios escolares. Já o Cenário 3 (combinação de torneiras eficientes e SAAP em coberturas convencionais (CC)), mostrou-se ideal a longo prazo, com reduções de consumo de até 60% e economias anuais superiores a 7.000 € + IVA, com retorno do investimento em 8 (CESMaria) e 7 anos (CESé). Outros cenários, que variam a proporção de CV e combinam SAAP com torneiras eficientes, também apresentaram reduções de consumo (até 58,83% no CESMaria e 60,73% no CESé) e economias financeiras (25%-60%). As CC mostraram maior eficiência na captação de água, com 93,84% de aproveitamento no CESMaria e 94,65% no CESé, utilizando reservatórios de 60 m³ e 70 m³, respectivamente. Já as CV’s reduziram a captação para 70%-90% devido à retenção de água pela vegetação, retendo entre 18,8% e 37,5% da água da chuva. Logo, as propostas promovem gestão hídrica sustentável, alinhando-se a objetivos econômicos e ambientais.
- Desenvolvimento e otimização de estruturas biomiméticas TPMS em impressão 3D para coalescência óleo-águaPublication . Souza, Caio Marco da Silva; Ribeiro, J.E.; Rocha, João; Przybysz, AldoO tratamento e a separação eficiente de emulsões óleo-água representam um desafio ecológico e econômico significativo para as indústrias petroquímica e metalmecânica. Esta dissertação investiga matrizes biomiméticas impressas em 3D, baseadas nas Superfícies Mínimas Triplamente Periódicas (TPMS), como potenciais meios coalescedores para o tratamento de efluentes. Com foco nas topologias Gyroid e Schwarz-D, os modelos foram fabricados em resina polimérica via estereolitografia mascarada (MSLA). Para alterar a hi-drofobicidade do material, aplicou-se uma hidrólise alcalina que visou à super-hidrofilicidade e ao comportamento oleofóbico subaquático na superfície, estratégias importantes para reduzir o fouling. Avaliações experimentais e por fluidodinâmica computacional (CFD) indicaram que as matrizes podem atuar como meios hidrodinamicamente ativos na coalescência. A estrutura Gyroid apresentou o melhor desempenho nas condições ensaiadas, possivelmente por favorecer condições hidrodinâmicas associadas à desestabilização do filme estérico dos surfactantes, alcançando uma eficiência de 90,46% após 4h de hidrólise alcalina, considerando um único ensaio. Apesar da maior resistência ao escoamento, sua tortuosidade contínua parece favorecer colisões, o que melhora a separação de fases. Conclui-se que a integração do design TPMS, impressão 3D e modificação superficial pode configurar uma solução replicável, sem consumíveis secundários e alinhada aos princípios da Economia Circular.
- Development of geopolymer-carbon composite for wastewater treatmentPublication . Silva, Lívia Firmani; Gomes, Helder; Pereira, Edilaine ReginaThe quality of wastewater treatment and the discharge of treated effluents remain major environmental issues, particularly due to the release of contaminants of emerging concern into aquatic environments as a result of insufficient tertiary treatment in wastewater treatment plants. Among these contaminants of emerging concern, pharmaceuticals such as carbamazepine, are frequently detected in wastewater and poses potential risks to water quality. In this context, the present study investigates the development of geopolymer and geopolymer-carbon composite subjected to a zeolitization process, produced from waste-derived materials. Fly ash was used as the primary precursor for geopolymer synthesis, while activated carbon was obtained from grape pomace. Comprehensive characterization was performed to assess the composition, structure, and surface properties of the synthesized materials. X-ray diffraction analysis revealed the presence of major crystalline phases, including quartz, hematite, and calcite, as well as the formation of zeolitic phases (Na-faujasite) in GP_HT2.0, whereas GP_AC_HT2.0 exhibited only calcite and gehlenite phases. Fourier Transform Infrared Spectroscopy spectra confirmed the presence of Si–O–T groups in the inorganic (FA, GP_M, GP_ HT1.0, GP_ HT1.5, GP _HT2.0, and GP_HT2.5) materials and carbon-related (–CH₂ and –CH₃ groups, C–O and C–O–C) bonds in the organic (WGP, AC_WGP, GP _AC, and GP _AC_HT2.0) materials. Additionally, acid–base characterization demonstrated the high basicity of all samples. BET analysis revealed a specific surface area of 427 m² g⁻¹ for AC, 30 m² g⁻¹ for GP_M, 181 m² g⁻¹ for GP _HT2.0, 48 m² g⁻¹ for GP_AC, and 139 m² g⁻¹ for GP_AC_HT2.0. Equilibrium analysis showed that the Langmuir model effectively described the adsorption process, indicating favorable conditions and strong affinity between the adsorbents and the adsorbate. Kinetic studies confirmed that all materials followed a pseudo-second-order model, the maximum adsorption capacities were determined as 4.2, 29.4, 39.7, and 30.6 mg g⁻¹ for GP_M, GP _HT2.0, GP_AC, and GP_AC_HT2.0, respectively.
- Gestão da eficiência hídrica em edifícios industriais: estudo de caso numa unidade da metalomecânicaPublication . Santos, Maria Aparecida Sidor dos; Silva, Flora; Kempka, MarianeEste estudo analisa o consumo de água numa unidade industrial do setor metalomecânico, localizada no nordeste de Portugal. Integra a análise dos consumos históricos da empresa, a aplicação de questionários aos utilizadores do edifício, o levantamento e caracterização dos dispositivos hidráulicos e a estimativa dos consumos associados às atividades operacionais. A análise do consumo de água dos últimos 10 anos revelou que o edifício apresenta um consumo anual médio de 7 500 m³, com redução significativa a partir de 2023. As atividades associadas ao consumo humano representam cerca de 55% do consumo total. A análise dos padrões de utilização dos equipamentos hidráulicos mostra elevada frequência de uso de sanitas e torneiras. O consumo total estimado associado ao uso humano é de aproximadamente 17 m³/dia, atingindo cerca de 4 100 m³/ano. Os consumos operacionais representam igualmente uma parcela relevante, estimados em 283 m³/mês, abrangendo processos industriais, lavagem de pavimentos, rega de áreas ajardinadas, serviços de cozinha e bebedouros. O consumo total global do edifício é de aproximadamente 625 m³/mês, sendo o consumo específico global estimado em 41,15 L/(utilizador·dia), valor próximo de estudos comparativos e no limite superior da literatura. Foram definidos três cenários de intervenção para melhoria da eficiência hídrica. O Cenário 1, de caráter comportamental, propõe ações de sensibilização dos utilizadores para promover hábitos de consumo mais eficientes, com elevado potencial de implementação. O Cenário 2, de caráter físico, contempla a substituição de torneiras e autoclismos por dispositivos mais eficientes, permitindo uma poupança estimada de 216 m³/ano e uma redução de aproximadamente 739 €/ano + IVA, com tempo de retorno do investimento de 4 anos. O Cenário 3, de caráter conceptual, integra Soluções baseadas na Natureza, aproveitamento de águas pluviais e aproveitamento de águas cinzentas, apresentando elevado potencial para reduzir a dependência de água potável e aumentar a resiliência hídrica em longo prazo. Conclui-se que a eficiência hídrica em edifícios industriais depende da integração entre tecnologia, gestão e comportamento dos utilizadores, constituindo uma oportunidade relevante para a redução de custos e promoção da sustentabilidade ambiental no setor industrial.
- Natural-based coagulants from chestnut shells for turbidity and color removal: toward sustainable wastewater treatmentPublication . Vieira, Juliana Akemy Inamine; Martins, Ramiro; Pietrobelli, Juliana MartinsTurbidity and color are critical parameters in industrial wastewater treatment, particularly in textile effluents containing suspended particles and dyes. Conventional coagulation methods are effective but have significant drawbacks. In this context, the development of natural coagulants has emerged as a promising alternative method. This study investigated the production of a natural-based coagulant from chestnut shells (Castanea sativa), an abundant agro-industrial residue in Portugal, through tannin extraction followed by chemical modification via the Mannich reaction. The tannin extraction process was statistically optimized using a Box-Behnken Design to evaluate the effects of pH, extraction time, and biomass dosage. The coagulant performance was evaluated using Jar Test assays for turbidity (kaolin) and color (methylene blue) removal. Statistical analysis showed that these factors affected turbidity and color removal differently, with higher extraction times and biomass dosage generally favoring turbidity removal. The results showed high turbidity removal efficiencies, reaching up to 96%, whereas color removal efficiencies were lower, reaching approximately 26%, suggesting that dye removal depends not only on coagulation mechanisms but also on specific interactions between the dye and the coagulant. Overall, the results demonstrate the potential of chestnut shell residues as a sustainable source of natural-based coagulants for wastewater treatment.
- Optimizing biogas production via ozone sludge pretreatmentPublication . Alqudah, Safaa Ahmad Mustafa; Martins, RamiroAnaerobic digestion (AD) is the preferred method for handling wastewater sludge while producing renewable energy in the form of biogas. However, this process often occurs during the hydrolysis phase, which can prevent the system from working at maximum efficiency. This study examined the effect of ozone pre-treatment on methane generation from municipal sludge during mesophilic batch digestion. Ozone was applied at concentrations of 0%, 5%, and 10% for exposure times of 30, 60, and 90 s, respectively. A series of anaerobic co-digestion experiments was then conducted using different inoculum-tosubstrate (I/S) ratios of 1.0, 1.5, and 2.0. Methane production was continuously monitored using the AMPTS II system. The methane yield was 736 NmL CH4 g-1 VS at an ozone concentration of 4.41 L min-1. The Buswell–Mueller equation was applied to estimate the theoretical biochemical methane potential (TBMP), resulting in a value of approximately 517 mL CH₄ per gram of volatile solids (VS). Kinetic modeling using the modified Gompertz equation showed faster methane production rates and reduced lag times under the optimized pretreatment conditions. Overall, the data suggest that ozone pretreatment, when carefully controlled, can significantly improve sludge biodegradability and enhance biogas yields, indicating a promising method for increasing energy recovery in wastewater treatment systems. Furthermore, a comparative evaluation of four kinetic models (Gompertz, Logistic, Transference, and Cone) was conducted to identify the most suitable approach for describing biogas production kinetics under ozone pretreatment. Although all models provided statistically robust fits, the Logistic and Gompertz models demonstrated slightly superior consistency and interpretability across the range of experimental conditions. This careful model selection not only improved the reliability of methane yield predictions but also supported more informed process optimization. Overall, these findings emphasize that integrating robust kinetic modeling with innovative pretreatment strategies can significantly enhance biogas yield and process efficiency, offering valuable insights into advancing sustainable energy recovery from municipal sludge.
- Surfactant removal from industrial effluents by moringa seed-assisted coagulation and photo-fenton oxidationPublication . Belgacem, Soufienne; Martins, RamiroWater pollution caused by surfactant-containing industrial effluents has become an important environmental concern due to the extensive use of detergents in domestic and industrial applications. Among these pollutants, sodium dodecyl sulfate (SDS) is one of the most widely used anionic surfactants and is frequently detected in wastewater because of its low biodegradability and adverse effects on aquatic ecosystems. Consequently, the development of efficient and sustainable treatment technologies for surfactant removal is of increasing importance. This study investigated the removal of SDS from synthetic industrial wastewater using a combined treatment consisting of Moringa oleifera seed-assisted coagulation followed by the Photo Fenton oxidation process. The coagulation stage was evaluated by studying the effects of coagulant dosage, initial surfactant concentration, and pH on SDS removal. Subsequently, the Photo Fenton process was optimized by evaluating the influence of pH, hydrogen peroxide dosage, ferrous ion concentration, and UV irradiation using Response Surface Methodology (RSM). The coagulation process achieved a maximum SDS removal efficiency of 55.6% under the optimum operating conditions. The subsequent Photo Fenton treatment significantly improved the removal efficiency, reaching 96% SDS removal. Process optimization using Response Surface Methodology predicted a maximum removal efficiency of 99.4% under the optimum conditions of pH 3, 1 mL of H₂O₂, 270 mg of FeSO₄·7H₂O, and a flow rate (Q) of 84 mL min⁻¹. The results demonstrate that combining Moringa oleifera-assisted coagulation with the Photo Fenton process is an effective and environmentally sustainable strategy for removing anionic surfactants from industrial wastewater. The integration of a natural coagulant with an advanced oxidation process provides a promising alternative for improving wastewater treatment efficiency while reducing reliance on conventional chemical treatments.
- Walnut shells and eucalyptus bark as green alternatives to chemical coagulants in water treatmentPublication . Aires, Isabella Kaminski; Martins, Ramiro; Pietrobelli, Juliana MartinsWater resource management has become a major technical and environmental challenge of the 21st century, largely driven by the intensification of industrial activities and the resulting generation of increasingly complex wastewater. Conventional coagulation–flocculation processes, widely used in wastewater treatment plants, mainly rely on inorganic chemical coagulants, such as aluminum and iron salts. Although effective, these chemicals have notable environmental and operational limitations. In response to these challenges, growing attention has been given to developing of more sustainable alternatives aligned with the principles of green chemistry. In this context, this study investigated the potential of natural coagulants derived from walnut shells (Juglans regia) and eucalyptus bark (Eucalyptus spp.) as environmentally friendly alternatives to conventional chemical coagulants. These lignocellulosic materials are rich in tannins, polyphenols, and other bioactive functional groups that promote coagulation primarily through charge neutralization and polymer bridging mechanisms. Unlike many approaches reported in the literature, which rely on raw powders or chemically activated adsorbents, this study employed saline-assisted liquid extracts, providing a milder, more more sustainable extraction route. The results demonstrated that eucalyptus bark exhibited superior turbidity removal performance, reaching 91%, while walnut shell achieved a maximum of 80%. For color removal using methylene blue, both biomaterials showed comparable performance, with maximum efficiencies of 48% for eucalyptus bark and 47% for walnut bark. A comparative analysis with the literature confirmed that the observed efficiencies were lower than those reported for chemically activated or highly optimized systems; however, they remained relevant within the context of green, low-cost, and minimally processed treatment strategies. This study advances environmentally friendly water treatment technologies by systematically comparing two forest residues under mild extraction conditions, supporting their potential application as scalable alternatives to conventional coagulants.