Evaluación de la eficiencia de adsorción de radón en aire mediante filtros de base de carbón activo y óxido de grafeno a tres diferentes proporciones

Abstract

The current research consists on evaluating the adsorption efficiency of 222Rn through activated coal filters and graphene oxide at different proportions. Activated coal was made using lignocellulosic waste from riñón tomato plant (solanum lycopersicum) through a pyrolysis system, so it can be chemically activated with the use of zinc chloride at 40%. For the characterization of adsorbent materials (CA and OG), it was necessary to apply the infrared spectroscopy technique (FT-IR), which allowed characterizing the materials in a physicochemical way, evidencing their main functional groups. In addition, the scanning electron microscopy (SEM) was used to observe the superficial characteristics of both, activated coal and graphene dioxide in a qualitative way, as well as determining the side size, porosity and particle size. The experimental configuration which allowed developing the trials to adsorb 222Rn into filters containing activated coal consisted on a closed system including a (20x20cm2) acrylic camera, a natural radioactive mineral (92% of 238U), a desiccant to absorb humidity (CaSO4), a set of pipes (vinyl), the PVC pipe filter holder, the adsorbent material and an alpha spectrometer (RAD7). For the validation of the experimental configuration, it was necessary to carry out leak rate tests in the closed system (camera, pipes, RAD7) resulting in 0,025 h-1 ± (0,12%) as well as the radon concentration activity in the laboratory (23,6 ± 7,52 Bq/m3). Finally, the activated coal adsorption coefficient is determined in 0,25 [m3/Kg] while the estimated value for the graphene oxide is 6066 [m3/Kg]. The first coefficient reported was determined through the experimental trials detailed in section 3.10 and the second one was calculated from the data obtained through a bibliographic revision.