Desenvolvimento de membranas de matriz mista baseadas em nanopartículas de sílica para captura de CO2

Abstract

CO2 is considered the major contributor to the global warming phenomenon and, because of this, efforts to develop technologies that aim to reduce atmospheric CO2 have been motivated. The main capture strategies are based on CO2/N2 separation, referring to post-combustion of organic material. Another important application involves the purification of methane from natural gas, capturing CO2 from the mixture CO2/CH4, what also intendes to reduce damage in the equipment, since this gas becomes corrosive in the presence of water. Gas permeation with membranes has advantages in CO2 capture. In order to overcome performance limitations presented by polymeric membranes, mixed matrix membranes (MMM) have been widely studied. This research has the proposal of developing MMM made with polyurethane and silica nanoparticles, and studing their performance in the permeation of mixtures containing CO2. TPD tests showed that the incorporation of functionalized silica with primary and secondary amino groups in membranes improved the sorption capacity of CO2. The most promising results in the pure gas tests were obtained at 1 bar, indicating facilitated transport for both MMM with 2.5% (w/w) silica functionalized with primary amino groups (Si-NH2) and for the one that received the same silica load with secondary amino groups (Si-NHR). Membranes of PU with 2.5% Si-NH2 improved CO2/N2 and CO2/CH4 selectivities in 98.4% and 54.2%, respectively, while membranes of PU with 2.5% Si-NHR led to eenhancements of 82.6% and 60.7% for the same selectivities.