Vermiculite as a potential component of the engineered barriers in low- and medium-level radioactive waste repositories

Vermiculite (VMT) was tested as a low-cost, eco-friendly adsorbent for the removal of cesium(I), strontium(II), europium(III), americium(III), and technetium(VII) radionuclides from aqueous solutions. The raw material was characterized and checked as potential adsorbent. The removal efficiency (E-r %) was studied as a function of the main factors important for the management of radioactive liquid wastes. It was found that the uptake from the aqueous solutions simulating the radioactive liquid wastes was in the order: Cs(I) - Sr(II) (both about 95%) > Am(III) (about 90%) > Eu(III) (about 80%). When a reducing agent is added to the solution technetium -99 may also be completely removed. The usefulness of VMT in liquid low level radioactive waste management has also been confirmed by checking its radiation stability. Vermiculite can be considered as a promising material for sorption of the radionuclides from radioactive waste solutions and as a potential additive to the engineered barriers in LLRW repositories.