Adsorption of Radon from a Humid Atmosphere on Activated Carbon

Abstract

Temperature and relative humidity can influence the adsorption capacity of radon on activated carbon to a great extent, depending on the physical properties of the carbon. Experiments were carried out to measure the radon uptake by an activated carbon in the presence of water vapor in a specially designed adsorption apparatus. The radon concentrations in the gas and solid phases were measured simultaneously once the adsorption equilibrium and the radioactive equilibrium between the radon daughter products were reached. The experiments in the presence of water vapor were carried out using two approaches. In one case the activated carbon was preequilibrated with water vapor prior to exposing it to radon. In the other case the carbon was exposed to a mixture of water vapor and radon. The uptake capacity for radon decreased substantially when both components were introduced together compared to when carbon was preequilibrated with water.

A qualidade do ar de interiores e a química

“…Paralelamente, materiais de construção de origem natural, tais como tijolo de argila, mármore e arenito, variam amplamente em concentração de radônio, e o nível de radônio em ambientes fechados pode aumentar consideravelmente pela emissão a partir desses materiais. A Agência de Proteção Ambiental dos Estados Unidos (U. S. EPA) tem estimado que a concentração de radônio em milhões de residências nos Estados Unidos é maior que o nível recomendado de 4 pCi/L, e classifica esse gás como um dos principais poluentes em recintos fechados, pois representa um sério risco à saúde da população 30 . Por outro lado, esse limite é discutível e varia de país para país.…”

Comparison of Radon Adsorption on Hematite and Charcoal Activated Powder in Air

“…Charcoal activated powder (activated carbon) and silica gel are often used as a possible protection against increased radon concentration due to diffusion, that is for its removal from the premises where people reside. [1,2] In recent years, new radon replacement adsorbents have also been tested, such as zeolites, i.e., zeolitic imidazole frameworks. [3,4] In addition, activated carbon is also used in one of the methods for the determining the average activity concentration of radon in the air which is in accordance with the International Standard for the Measurement of radioactivity in the environment -Air: radon-222.…”