RESUMO
It is possible to take advantage of shallow reservoirs (<300 m) for CO2 capture and storage in the post-combustion process. This process is called enhanced carbon capture and storage (e-CCS). In this process, it is necessary to use a nano-modifying agent to improve the chemical-physical properties of geological media, which allows the performance of CO2 selective adsorption to be enhanced. Therefore, this study presents the development and evaluation of carbon sphere molecular nano-sieves (CSMNS) from cane molasses for e-CSS. This is the first report in the scientific literature on CSMNS, due to their size and structure. In this study, sandstone was used as geological media, and was functionalized using a nanofluid, which was composed of CNMNS dispersed in deionized water. Finally, CO2 or N2 streams were used for evaluating the adsorption process at different conditions of pressure and temperature. As the main result, the nanomaterial allowed a natural selectivity towards CO2, and the sandstone enhanced the adsorption capacity by an incremental factor of 730 at reservoir conditions (50 °C and 2.5 MPa) using a nanoparticle mass fraction of 20%. These nanofluids applied to a new concept of carbon capture and storage for shallow reservoirs present a novel landscape for the control of industrial CO2 emissions.
RESUMO
As an alternative to eliminating cancer cells with minimal impacts on the nearby tissues, biocompatible nanoparticles based on silica-coated carbon nano-onions, with outstanding photothermal efficiency, are presented. Metal-doped carbon nano-onion@SiO2 materials are produced using flame synthesis. Metal complexes are injected in the flame to tune the carbon organization levels, which results in materials with excellent photostability and total photothermal conversion efficiency, regarding the incident light input, as higher as 48% for 785 nm laser. It was found that the metal dopant, even at a very low content, plays an interesting role in photothermal efficiency. We tested the effect of thin silica layers on the carbon nanosphere, first as a way to improve biocompatibility and provide a more reactive surface toward the modifications process to add vectorizing agents. Despite the primary goal of the silica shell, a notable increase in photothermal efficiency was observed. In vivo studies of the biological response to the materials as probed by the zebrafish model found that the as-prepared carbon nanospheres and the SiO2-coated particles are highly biocompatible. The SiO2-coated samples were found to be more suitable for photothermal application, due to the higher colloidal stability and higher photothermal efficiency.