Avaliação da MOF HKUST-1 como adsorvente em pó e em leitos estruturados por impressão 3D

Abstract

As a consequence of widespread using of fossil fues, carbon dioxide (CO2) levels in Earth’s Atmosphere has significantly increased over the last centuries, thus contributing to an intensification of Greenhouse Effect, which is the main factor involved in increasing Earth’s average temperature. Furthermore, CO2 in Atmosphere contributes to the phenomenon of Acid Rain, and, for these two reasons, it’s necessary to develop of efficient method of removal of this gas from atmospheric air. The presence of 4-nitrophenol in water boedies may inflict dangerous effects on the health of human beings, and the presence of nitrogenous organic pollutants might accelerate the phenomenon of Eutrophication, which might might promote ecological imbalance in aquatic ecosystems. In this context, the use of adsorbent materials is a possible metodology of pollutants removal from both Hydrosphere and Atmosphere, and, in the case of removing CO2, using materials that catalyse the hydrogenation reaction of this gas could promote the production of fuels. Metal-Organic Frameworks (MOFs) are promising materials in these application fields, including MOF HKUST-1, constituted of cupper and trimesid acid, but application of this material in powder form might not be viable for treatment of atmospheric air and water bodies, due to difficulty of handling a powdered material. The aim of this work was to produce adsorvent HKUST-1 monoliths by additive manufacturing (3D printing) and to evaluate the applicability of HKUST-1 as an adsorvent in form of powder and in form of monoliths obtained by 3D printing. In order to fulfill this goal, MOF HKUST-1 was sintetized from copper(II) acetate and trimesic acid. An ink was obtained from HKUST-1, bentonite and water, following the mass ratio of 4:1 for HKUST-1 and bentonite. Powdered MOF HKUST-1 was subjected to 4-nitrophenol adsorption assays in aquous solution with and without previous activation procedure. A MOF HKUST-1 adsorbent monolith was subjected to safranin adsorption and desorption assays in aquous solution. The masses of 3D printed monoliths of MOF HKUST-1 were found to be, in average, 607,2 mg. Using Fourier transform infrared vibrational spectroscopy (FTIR), the chemical structure of MOF HKUST-1 was found to be maintained during the 3D printing procedure, and evidence was found indicating that 4-nitrophenol was adsorbed. An HKUST-1 monolith obtained through 3D printing was found to undergo fragmentation when immersed in aqueous solution, although it remained stable when exposed to atmospheric air, which indicates that, although application of the printed material in aquous solution is not viable, the monoliths produced in this work could be later subjected to CO2 adsorption assays and to CO2 hydrogenation catalysis assays.