Changes in the pH of radioactive aqueous solutions in their decontamination by means of two carbon adsorbents

摘要

A wood charcoal, manufactured in Extremadura (Spain), and a oxidized carbon obtained by an air treatment at 250 ℃ fromrnthis charcoal have been used to eliminate radioactive cations by filtration beds from natural waters. Here, it is studied thernchanges in the pH of radioactive aqueous solutions in their decontamination. The results show that the carbon adsorbentsrnexert a different influence on the initial pH of radiactive aqueous solutions. Independent of the carbon used, the final pH isrnapproximately 7 if the initial solutions are acid. In contrast, the pH do not changes if basic solutions are filtered through thernoriginal charcoal, and tends to decrease slightly using the carbon resulting of air treatment. Theses changes are attributed tornsoluble mineral matter which carry the carbon adsorbents; to a different surface oxygen groups on their surfacesrncaused by the air treatment; and to a different p basicity of their exposed graphene layers.