Doutorado em Química

URI Permanente para esta coleção

http://repositorio.ufes.br/handle/10/17501

Nível: início
Ano de início: 2014
Conceito atual na CAPES: 5
Ato normativo: Homologação da 85ª Reunião do CTC-ES, Parecer CNE/CES nº 163/2005.
Processo nº 23001.000081/2005-56 do Ministério da Educação.
Publicado no DOU 28/07/2005, seção 1, página 11)
Periodicidade de seleção: Anual
Área(s) de concentração: Química
Url do curso: https://quimica.vitoria.ufes.br/pt-br/pos-graduacao/PPGQ/detalhes-do-curso?id=956/a>

Navegar

Navegando Doutorado em Química por Autor "Almeida, Luiz Carlos Pimentel"

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura disponível
    Item
    Estudo da miscibilidade de blendas poliméricas : influência na morfologia e eficiência de membranas
    (Universidade Federal do Espírito Santo, 2024-12-03) Lima, Rayanne Penha Wandenkolken; Silva Filho, Eloi Alves da ; https://orcid.org/0000-0002-9306-7882; http://lattes.cnpq.br/8259708288584235; https://orcid.org/0000-0001-8558-302X; http://lattes.cnpq.br/2557592261324003; Almeida, Luiz Carlos Pimentel; http://lattes.cnpq.br/0064380963494664; Prado, Adilson Ribeiro ; https://orcid.org/0000-0001-8808-4488; http://lattes.cnpq.br/3085491325255749; Dalmaschio, Cleocir José ; https://orcid.org/0000-0002-3773-5786; http://lattes.cnpq.br/5209978120430790; Machado, Marta Albuquerque ; https://orcid.org/0000-0001-8335-3351; http://lattes.cnpq.br/5991893415892784
    Sustainability, understood as social and environmental responsibility, is a fundamental principle for mitigating the environmental challenges associated with the production and disposal of plastics. In this context, the present work aims to correlate the morphology of membranes obtained via Non-Solvent Induced Phase Separation (NIPS) from polymer blends with the miscibility analysis of the blends themselves. Two blends were prepared for this purpose: the first composed of two semi-crystalline polymers, one of recycled origin and the other of green origin; and the second composed of one semi-crystalline polymer and one amorphous polymer, both recycled. The miscibility of the blends was evaluated using DSC and confirmed through dynamic mechanical analysis (DMA). The first blend demonstrated partial immiscibility, with a reduction in the equilibrium melting temperature (Tºm) and showed three glass transition peaks (Tg), indicating separate phases. The Flory-Huggins interaction parameter (χ12) for this blend was positive (1.115 × 10⁻⁴), indicating a barrier to total miscibility. The resulting membranes presented a dense, spongy and homogeneous morphology, with macrovoid formation. Permeability and porosity analyses indicated potential for nanofiltration or reverse osmosis applications. Meanwhile, the second blend exhibited two Tg peaks, suggesting miscibility relative to its composition, with a negative χ12 (-2.057 × 10⁻⁴), indicating favorable interactions, though insufficient for complete miscibility. Morphological analysis of these membranes revealed the presence of macrovoids associated with partial immiscibility and thermodynamic instability, resulting in lower selectivity and mechanical resistance. These characteristics classify them for ultrafiltration-type applications
  • Nenhuma Miniatura disponível
    Item
    Óxidos Mistos (ZnO/Fe2O3/ZnFe2O4@SiO2) Reciclados a Partir de Baterias de Zn-MnO2 e Rejeitos de Mineração de Ferro Aplicados como Fotocatalisadores, Pseudocapacitores e Sensores Eletroquímicos
    (Universidade Federal do Espírito Santo, 2024-02-02) Magnago, Luma Barbosa; Lelis, Maria de Fátima Fontes; https://orcid.org/0000-0002-4828-4482; http://lattes.cnpq.br/9047743898158654; Freitas, Marcos Benedito José Geraldo de; https://orcid.org/0000-0003-1521-774X; http://lattes.cnpq.br/3485939623614913; https://orcid.org/0000-0002-5271-5572; http://lattes.cnpq.br/4135641802415178; Garcia, Eric Marsalha; https://orcid.org/0000-0002-3731-7568; http://lattes.cnpq.br/8006969980460016; Almeida, Luiz Carlos Pimentel; https://orcid.org/; http://lattes.cnpq.br/0064380963494664; Morais, Verônica Santos de; https://orcid.org/0000-0002-7324-2057; http://lattes.cnpq.br/3680926664416715; Ferreira, Sandra Aparecida Duarte; https://orcid.org/0000-0002-4828-4482; http://lattes.cnpq.br/5439516820869374
    In this study, mixed oxides were prepared using spent alkaline battery anodes, silt fraction (FS), and raw iron mining reject (RB), and applied as photocatalysts, pseudocapacitors, and electrochemical sensors. Characterization analyses revealed that the mixed oxides (FS) and (RB) are composed of SiO2, ZnO, Fe2O3, ZnFe2O4, and are formed by agglomerates of nanoscale particles with a diameter < 200 nm and cubic shapes. For the photocatalytic study, a complete 23 factorial design was conducted to determine the optimal conditions of pH, H2O2 quantity, and the mass of mixed oxide (FS) or (RB) required for the decolorization of 1.56 x 10-6 mol of methylene blue dye (AM) under solar irradiation. The maximum decolorization efficiency was 96 % after 30 min using mixed oxide (FS) and 90 % after 45 min using mixed oxide (RB) with 2.35 x 10-5 mol of H2O2 and 20 mg of the material at pH 3. The efficiencies remained unchanged even after four successive decolorization cycles, and no solution after treatment showed toxicity in the Allium cepa (onion seed) test. In electrochemical studies, mixed oxide (FS) exhibited favorable characteristics for pseudocapacitor application due to its high capacitance (87.16 F g -1 ), energy density (27.24 Wh kg-1 ), power density (524.41 W kg -1 ), and reversibility (93 %). On the other hand, mixed oxide (RB) showed better sensitivity for use as an ascorbic acid (AA) sensor, with a value of 0.23 A mol-1 L cm-2 . This study encompasses recycling of waste and rejects to prepare new materials with multifunctional applications, contributing to environmental sustainability, preservation of raw materials, and the generation of a circular economy.