Estudo da caracterização de sílica do tipo SBA-15,funcionalizada: novo materiais para remediação de sistemas aquosos contaminados com metais potencialmente tóxicos, utilizando Pb2+ como poluente modelo

• Ano de defesa: 2014
• Autor(a) principal: Silva, Fernanda Alves da [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: SBA-15; Functionalization; Chitosan; APTMS; EDTA; Heavy metals; Funcionalização; Quitosana; Metais potencialmente tóxicos
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=739336; http://repositorio.unifesp.br/handle/11600/47749

Heavy metals are among the most harmful aquatic contaminants. Therefore, there is a growing interest in obtaining materials adsorbents to capture these contaminants from effluent In this work the synthesis of mesoporous silica SBA-15 and its functionalization with aminopropyltrimethoxysilane (APTMS) , chitosan (QTS) and ethylenediaminetetraacetic acid (EDTA) were carried out in order to compare the functionalization of silicatic support with different organic agents and apply the new materials as adsorbents to uptake heavy metals from water. The functionalization of SBA-15 with APTMS was based on the post-synthesis grafting method, in toluene, and the EDTA and QTS incorporation were made by impregnation method, using dichloromethane and 2 % aqueous acetic acid as solvent, respectively. APTMS, EDTA, QTS, SBA-15 and new obtained materials (SBA-15/APTMS, SBA-15/QTS, SBA-15/EDTA, SBA-15/APTMS/QTS and SBA-15/APTMS/EDTA) were characterized by analytical and physical chemistry techniques: Thermogravimetry / Derivative Thermogravimetry (TG / DTG), Differential Scanning Calorimetry (DSC), Elemental Analysis (EA), Adsorption/Desorption of Nitrogen, Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Regarding functionalized samples, the functionalization of SBA-15 with APTMS there was effective and about 30% of agent was incorporated to silica, as all results showed. The incorporation of chitosan was effective in SBA-15 supported functionalized with APTMS and also to the pure support, presenting an increase of the thermal stability of the polymer impregnated to silica. Regarding the incorporation of EDTA, there was no experimental evidence that indicates incorporation of the agent to the substrate. Furthermore, it was found that stirring times had little influence on incorporation of the actives. The preliminary tests of sorption of Pb2+ in aqueous media showed SBA-15/APTMS and SBA-15/APTMS/QTS samples presented the best results, with sorption of 100.0% and 39.5% of the lead present in the solution, respectively. On the other hand, the sample of pure commercial quitosan retained 99.1% of Pb2+ ions in the solution after 30 minutes of contact.