Preparação e caracterização de hidrogéis magnéticos á base de carragenas para a remoção de metais pesados de águas residuais

• Ano de defesa: 2015
• Autor(a) principal: Maciel, Diana José
• Orientador(a): Mello, Ivana Lourenço de
• Banca de defesa: Leite, Marcia Christina Amorim Moreira , Rojas, Edwin Gonzalo Azero
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Química
• Departamento: Centro de Tecnologia e Ciências::Instituto de Química
• País: BR
• Palavras-chave em Português: Hidrógeis magnéticos; carragenas; cádmio; chumbo; maghemita
• Palavras-chave em Inglês: Magnetic hydrogels; carrageenan; cadmium; lead; maghemite
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA::ANALISE DE TRACOS E QUIMICA AMBIENTAL
• Link de acesso: http://www.bdtd.uerj.br/handle/1/15797

The purpose of this dissertation was to prepare, characterize and apply magnetic hydrogels based on carrageenans (Kappa and Iota) in the removal of metal ions (Cd and Pb) of aqueous effluents. For this reason, we evaluated the ratio kappa (κ) and iota (ι) carrageenan and the influence of the crosslinking agent (KCl and CaCl2) in different concentrations (0.3 mol.L-1 and 0.5 mol.L-1) on the properties of hydrogels. The results showed that the synthesized magnetic material consisted mostly of maghemite (Fe2O3) and showed superparamagnetic behavior. Magnetic- hydrogels based on carrageenan with relatively spherical morphology and a particle size in the range 710 - 850 μm were prepared. TEM images showed that the magnetic material was in nanosize. The magnetic hydrogels crosslinked with potassium ions presented good thermal stability and degree of swelling in water exceeding 500%. As for the magnetic hydrogels crosslinked with CaCl2.2H2O showed relatively low thermal stability and degree of swelling values below 100%. Both magnetic nanoparticles as crosslinking agents (KCl and CaCl2), were well distributed on the surface of hydrogels. The hydrogels showed superparamagnetic behavior and responded to the stimulus of a magnet. The magnetic hydrogels were applied in the removal of ions (Pb2+ and Cd2+) from aqueous solutions. The magnetic hydrogels based on k-carrageenan crosslinked with 0.3 mol L-1 KCl, were the ones with the best removal percentage (35%) for Pb 2+ ions. As for the removal of Cd2 +, magnetic hydrogels prepared by mixing (k + i) - carrageenan, crosslinked with 0.3 mol L-1 KCl, were the best percentages obtained for the removal of these ions (40%)