Otimização da síntese das zeólitas NaA e NaX utilizando radiação de micro-ondas para aplicação como agentes hemostáticos coagulantes
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Data
2017-07-18
Autores
Povinelli, Ana Paula Ribeiro [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A substituição da fonte de calor convencional por fontes de radiação de micro-ondas vem sendo bastante explorada na área de síntese de sólidos inorgânicos devido ao seu eficaz mecanismo de entrega de energia que proporciona rapidez no processo de síntese além de gerar materiais com maior pureza de fase. Neste contexto, o presente trabalho visou a otimização das sínteses das zeólitas NaA e NaX utilizando radiação de micro-ondas e a caracterização utilizando as técnicas de DRX (Difração de Raios-X), MEV (Microscopia eletrônica de varredura) e EDS (Energy-dispersive X-Ray Spectrocopy). As zeólitas foram sintetizadas e caracterizadas visando a posterior aplicação como agentes hemostáticos coagulantes. Os experimentos mostraram que a zeólita NaA obtida utilizando radiação de micro-ondas durante 30 minutos possui as mesmas características da zeólita NaA sintetizada utilizando aquecimento convencional por 48 horas, indicando que com a utilização da radiação foi possível alcançar uma redução de 98,96% no tempo de síntese. A aplicação de aquecimento de micro-ondas na síntese da zeólita NaX também provou decréscimo no tempo de síntese quando comparado ao aquecimento convencional, entretanto os dados de microscopia eletrônica revelaram que a zeólita sintetizada pelo aquecimento de micro-ondas estavam aglomeradas. A fim de tornar o coloide mais estável, foi feita a estabilização estérica dessas zeólitas através da esterificação dos grupos silanóis presentes na superfície das mesmas utilizando 1-propanol e 1-butanol. Os dados MEV mostraram que a modificação foi eficiente e que a dispersão foi estabilizada após o tratamento. Em relação ao potencial das zeólitas como agentes hemostáticos coagulantes, os dados de tromboelastografia mostraram que as zeólitas NaA e NaX provocaram diminuição no tempo necessário para a formação e crescimento do coágulo porém, dentre todas as zeólitas avaliadas, a zeólita NaX sintetizada por aquecimento convencional se destacou como agente hemostático apresentando uma redução de 6 minutos no tempo de formação do coágulo.
Conventional heat source has been substituted by microwave heat source in many chemical reactions including inorganic solids syntheses, since the microwave heat source can accelerate the energy delivery. Because of that, it is possible to obtain syntheses in a shorter time and materials obtained have a higher purity phases. Zeolites were synthesized and characterized aiming to zeolites hemostatic agents application. In this context, this work aimed to synthesize NaA and NaX zeolites employing microwave radiation and to characterize materials obtained using XRD (X-Ray Diffraction), SEM(Scanning Electron Microscopy) and EDS (Energy-dispersive X-Ray Spectrocopy) techniques. NaA zeolite obtained by microwave radiation after 30 minutes showed the same characteristics of NaA zeolite obtained by conventional heat after 48 hours. In other words, the substitution of the heat source reduced 98,96% the synthesis time. Related to NaX zeolite, microwave radiation also reduced the synthesis time, however SEM and EDS data showed some differences between NaX obtained by conventional and NaX obtained by microwave heating. It was also observed by SEM that the colloidal system of NaX obtained by microwave radiation has agglomerated. In order to stabilize sterically the colloid, NaX surface was functionalized by silanols groups esterification using 1-propanol and 1-butanol alcohols. SEM data showed that steric stabilization was successful. Regarding the potential of the zeolites as hemostatic coagulating agents, thromboelastography data showed that NaA and NaX zeolites caused decrease in time required for clot formation and growth. However, among all the zeolites evaluated, NaX zeolite synthesized by conventional heating had better results as a hemostatic agent showing a reduction of 6 minutes in clot formation time.
Conventional heat source has been substituted by microwave heat source in many chemical reactions including inorganic solids syntheses, since the microwave heat source can accelerate the energy delivery. Because of that, it is possible to obtain syntheses in a shorter time and materials obtained have a higher purity phases. Zeolites were synthesized and characterized aiming to zeolites hemostatic agents application. In this context, this work aimed to synthesize NaA and NaX zeolites employing microwave radiation and to characterize materials obtained using XRD (X-Ray Diffraction), SEM(Scanning Electron Microscopy) and EDS (Energy-dispersive X-Ray Spectrocopy) techniques. NaA zeolite obtained by microwave radiation after 30 minutes showed the same characteristics of NaA zeolite obtained by conventional heat after 48 hours. In other words, the substitution of the heat source reduced 98,96% the synthesis time. Related to NaX zeolite, microwave radiation also reduced the synthesis time, however SEM and EDS data showed some differences between NaX obtained by conventional and NaX obtained by microwave heating. It was also observed by SEM that the colloidal system of NaX obtained by microwave radiation has agglomerated. In order to stabilize sterically the colloid, NaX surface was functionalized by silanols groups esterification using 1-propanol and 1-butanol alcohols. SEM data showed that steric stabilization was successful. Regarding the potential of the zeolites as hemostatic coagulating agents, thromboelastography data showed that NaA and NaX zeolites caused decrease in time required for clot formation and growth. However, among all the zeolites evaluated, NaX zeolite synthesized by conventional heating had better results as a hemostatic agent showing a reduction of 6 minutes in clot formation time.
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Palavras-chave
Zeólitas, Micro-ondas, Coagulação, Zeolites, Microwaves, Coagulation