Síntese e caracterização de Metal-Organic Framework (MOF) para uso na adsorção de CO2

Abstract

Growing concern about global warming and reducing greenhouse gas emissions in the atmosphere has driven the development of technological options to reduce the negative impacts of human activities, and CO2 capture and storage is one of them. Solid adsorbent materials are being used with the aim of adsorbing polluting gases. Metal-Organic Frameworks (MOFs) are a class of porous materials of great potential for adsorption of greenhouse gases, formed by the connection of metallic ions and organic binders. In this context, the objective of this work is to synthesize the MOF of type NH2-MIL-53(Al), to characterize and evaluate its use in the adsorption of carbon dioxide. For synthesis of the MOF, a hydrothermal process was used in a PFA closed reactor (155 °C) with subsequent washes and resuspensions, obtaining an average mass yield of 90%. The obtained MOF was characterized with the use of the techniques such as SEM-FEG-EDS, elemental analysis, FAAS, XRF, FTIR, TGA, XRD/Refinement by the Rietveld Method and MAS-NMR, exhibiting characteristics of the structure NH2-MIL-53(Al). For the adsorption and desorption tests of CO2 the synthesized material was used as a powder in a fixed bed system. The synthesized MOF presented CO2 adsorption capacity of 0.13 mmol g-1 and SBET of 27 m2 g-1, lower than that reported in the literature, which were attributed to the presence of occluded binder in the pores of the material. The calculated average cost for the synthesis of the MOF in the laboratory was 34% of the value of the non-functionalized commercial standard available in the market. The residual solvent purification process from the MOF synthesis proved to be satisfactory, completely removing the DMF and with a residual contribution of methanol of only 0.00008%.