Sílicas mesoporosas HMS e MCM-41 modificadas com grupos contendo nitrogênio e enxofre como adsorventes para íons metálicos em solução.

• Ano de defesa: 2012
• Autor(a) principal: Germano, Ana Fernanda de Souza
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraí­ba; BR; Química; Programa de Pós-Graduação em Química; UFPB
• Palavras-chave em Português: Sílica mesoporosa; Organofuncionalização; Adsorção de metais pesados; Mesoporous silica; Organofunctionalization; Adsorption heavy metals; CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/7077

Mesoporous organic-inorganic hybrids are promising candidates in the field of adsorption. In this work new adsorbents based on mesoporous silica MCM-41 and HMS types organofunctionalized with groups containing nitrogen and sulfur using the method after functionalization were synthesized. The HMS silica was obtained from neutral n-dodecylamine surfactant and modified with organosilanes containing one, two or three nitrogen atoms, then submitted to the functionalization reaction with mercaptoacetic acid or ethylene sulfide. The MCM-41 silica, obtained from CTAB template was modified with the organosilane containing one nitrogen atom and functionalized with carbon disulfide. The set of HMS functionalized silicas were used in the adsorption process of divalent cations Cd, Co, Cu, Ni and Pb from aqueous solution and kinetic study. All HMS and MCM-41 matrices were characterized through elemental analysis, thermogravimetry, surface area, infrared spectroscopy, nuclear magnetic resonance of 13C and 29Si and X-ray diffraction techniques. The elemental C, H, N and S analysis suggest success on the immobilization of ethylene sulfide, thioglycolic acid ligands, pointing probably to an ethylene sulfide molecules polymerization. The matrix MCM-41 showed a small degree functionalization, 0.09 mmol g -1 of sulfur anchored to the surface. HMS functionalized matrices demonstrated having adsorption capacity of Cd2+, Co2+, Cu2+, Ni2+ and Pb2+, being the best results observed for Cu2+ cation. All systems studied obey the pseudo-second order kinetics of reaction. The values of Cu2+ ions adsorbed on the matrices HMS containing one, two or three nitrogen atoms and mercaptoacetic acid were 0.86, 1.08 and 1.06 mmol g-1, respectively. For matrices containing one, two or three nitrogen atoms and ethylene sulfide, values were 0.83, 1.38 and 1.01 mmol per gram, respectively.