Navegando por Palavras-chave "adsorption"
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- ItemSomente MetadadadosBehavior of human immunoglobulin G adsorption onto immobilized Cu(II) affinity hollow-fiber membranes(Wiley-Blackwell, 2013-10-01) Borsoi-Ribeiro, Mariana; Lazzarotto Bresolin, Igor Tadeu [UNIFESP]; Vijayalakshmi, Mookambeswaran; Alves Bueno, Sonia Maria; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP); Univ Technol Compiegne; VIT Univ VelloreIminodiacetic acid (IDA) and tris(2-aminoethyl)amine (TREN) chelating ligands were immobilized on poly(ethylene vinyl alcohol) (PEVA) hollow-fiber membranes after activation with epichlorohydrin or butanediol diglycidyl ether (bisoxirane). the affinity membranes complexed with Cu(II) were evaluated for adsorption of human immunoglobulin G (IgG). the effects of matrix activation and buffer system on adsorption of IgG were studied. Isotherms of batch IgG adsorption onto finely cut membranes showed that neither of the chelates, IDA-Cu(II) or TREN-Cu(II), had a Langmuirean behavior with negative cooperativity for IgG binding. A comparison of equilibrium and dynamic maximum capacities showed that the dynamic capacity for a mini-cartridge in a cross-flow filtration mode (52.5 and 298.4mgg(-1) dry weight for PEVA-TREN-Cu(II) and PEVA-IDA-Cu(II), respectively) was somewhat higher than the equilibrium capacity (9.2 and 73.3mgg(-1) dry weight for PEVA-TREN-Cu(II) and PEVA-IDA-Cu(II), respectively). When mini-cartridges were used, the dynamic adsorption capacity of IDA-Cu(II) was the same for both mini-cartridge and agarose gel. Copyright (c) 2013 John Wiley & Sons, Ltd.
- ItemAcesso aberto (Open Access)Effects of temperature and particle size on the adsorption of Remazol Golden Yellow RNL in activated carbon(Univ Estadual Maringa, Pro-reitoria Pesquisa Pos-graduacao, 2009-01-01) Besinella Junior, Expedito; Matsuo, Melissa Souza; Walz, Mabel; Silva, Aracelis Ferreira da; Silva, Classius Ferreira da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Ctr Biotecnol Amazonia; Univ Estadual Oeste ParanaTextile industries have environmental problems due to high levels of COD and color. Adsorption is one of the most important processes used to remove color from effluent. Adsorption isotherms of Remazol Gold Yellow Remazol RNL reactive dye in activated carbon were determined. Two parameters were studied: temperature (30 and 40 degrees C) and particle size (1.70 +/- 0.30 mm e 3.00 +/- 0.40 mm). Results show that an increase in temperature or a decrease in particle size promotes in increase in the adsorption. the Langmuir-Freundlich equation was the best-fitted model for the experimental data.
- ItemSomente MetadadadosEvidences for charge-transfer complex formation in the benzene adsorption on sulfated TiO2-a resonance Raman spectroscopy investigation(Wiley-Blackwell, 2008-03-01) Noda, L. K. [UNIFESP]; Rosales, R.; Goncalves, N. S. [UNIFESP]; Sala, O.; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Santa Catarina (UFSC); Universidade de São Paulo (USP)Benzene adsorbed on highly acidic sulfated TiO2 (S-TiO2) shows an intriguing resonance Raman (RR) effect, with excitation in the blue-violet region. There are very interesting spectral features: the preferential enhancement of the e(2g) mode (1595 cm(-1)) in relation to the a(1g) mode (ring-breathing mode at 995 cm(-1)) and the appearance of bands at 1565 and 1514 cm(-1). the band at 1565 cm(-1) is probably one of the components of the e(2g) split band, originally a doubly degenerate mode (8a, 8b) in neat benzene, and the band at 1514 cm(-1) is assigned to the 19a mode, an inactive mode in neat benzene. These facts indicate a lowering of symmetry in adsorbed benzene, which may be caused by a strong interaction between S-TiO2 and the benzene molecule with formation of a benzene to Ti (IV) charge transfer (CT) complex or by the formation of a benzene radical cation species. However, the RR spectra of the adsorbed benzene cannot be assigned to the benzene radical cation because the observed wavenumber of the ring-breathing mode does not have the value expected for this species. Moreover, it was found by ESR measurements that the amount of radicals was very low, and so it was concluded that a CT complex is the species that originates the RR spectra. the most favorable intensification of the band at 1595 cm(-1) in the RR spectra of benzene/S-TiO2 at higher excitation energy corroborates this hypothesis, as an absorption band in this energy range, assigned to a CT transition, is observed. Copyright (C) 2008 John Wiley & Sons, Ltd.
- ItemAcesso aberto (Open Access)Poluentes emergentes no meio ambiente: uma revisão da literatura(Universidade Federal de São Paulo, 2023-11-24) Garcia, Renan Affonso Salas [UNIFESP]; Bresolin, Igor Tadeu Lazzarotto [UNIFESP]; Pinheiro, Cláudio Pereira; http://lattes.cnpq.br/5750111176589237Nesse trabalho de conclusão de curso, aborda-se o crescimento dos estudos relacionados aos poluentes no meio ambiente e seus descartes, um panorama da evolução das Leis Federais brasileiras e seus órgãos competentes no combate à poluição aquática no país. Com aprofundamento na caracterização dos principais poluentes e seus aspectos de diferenciação e origens. A fim de estudar as diferenças entre poluentes e micropoluentes e estudar quais os principais micropoluentes emergentes, os impactos para o meio ambiente e população em um geral. Esse trabalho é uma revisão bibliográfica de forma a evidenciar como os artigos científicos tratam o assunto de micropoluentes emergentes com o passar dos anos, como principal referência a base da Web of Science. Como objetivo principal do trabalho, buscou-se dois estudos de caso importantes para a sociedade, os compostos Azitromicina e Metformina, medicamentos largamente produzidos e consumidos nos dias atuais. Características, posologia, quantidades produzidas pela industria farmacêutica e resíduos, são pontos abordados de forma mais profunda. Ao final, se aborda as principais técnicas e tecnologias para remoção dos compostos estudados, assim como o papel do Engenheiro Químico na diminuição dos impactos ambientais promovidos por ambos compostos abordados. Conclui-se por meio deste trabalho que a legislação ambiental não aborda os micropoluentes diretamente e os métodos convencionais de tratamento de efluentes não é eficiente na remoção desses compostos, portanto os métodos da engenharia química abordados no trabalho são importantes para mudar esse cenário.
- ItemAcesso aberto (Open Access)Remoção de Pb2+ e Cr3+ em solução por zeólitas naturais associadas a rochas eruptivas da formação serra geral, bacia sedimentar do Paraná(Sociedade Brasileira de Química, 2009-01-01) Shinzato, Mirian Chieko [UNIFESP]; Montanheiro, Tarcísio José; Janasi, Valdecir de Assis; Andrade, Sandra; Yamamoto, Jorge Kazuo; Universidade Federal de São Paulo (UNIFESP); Secretaria do Meio Ambiente do Estado de São Paulo Instituto Geológico; Universidade de São Paulo (USP)The capacity of natural zeolites and its host rock (dacite) to remove Pb2+ and Cr3+ from aqueous solutions has been investigated. Results showed that both samples prefer to remove Pb2+ instead of Cr3+. Almost 100% of Pb2+ was removed from solutions with concentration until 50 mg L-1 and 100 mg L-1 of this metal, respectively by dacite and zeolite. The equilibrium of metals adsorption process was reached during the first 30 min by both materials. Na+ can be used to recover Pb2+, but not to remove Cr3+ from the treated samples. The Sips model showed a good fit for experimental data of this study.
- ItemSomente MetadadadosSpray-dried chitosan microspheres containing 8-hydroxyquinoline-5 sulphonic acid as a new adsorbent for Cd(II) and Zn(II) ions(Elsevier B.V., 2008-03-01) Vitalia, Luciano; Laranjeira, Mauro C. M.; Goncalves, Norberto S. [UNIFESP]; Favere, Valfredo T.; Universidade Federal de Santa Catarina (UFSC); Universidade Federal de São Paulo (UNIFESP)In the present study, a new chelating adsorbent was prepared from chitosan microspheres cross-linked with glutaraldehyde by spray drying using 8-hydroxyquinoline-5 sulphonic acid as chelant agent (CTS-SX-CL). Microspheres of the new adsorbent were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). the effect of pH, contact time and concentration of metallic ions in solution were evaluated on the adsorption behavior of Cd(II) and Zn(II) by CTS-SX-CL. Adsorption was maximum for both Cd(II) and Zn(II) at pH 8.0. Adsorption kinetic curves were obtained and could be fit by the pseudo second-order adsorption model. An analysis of equilibrium adsorption data using the Langmuir isotherm model indicated that the maximum adsorption capacity of CTS-SX-CL was higher than that of CTS-CL for both ions investigated. the adsorption capacity increased 74% for Cd(II). (C) 2007 Elsevier B.V. All rights reserved.