Pre-impregnation approach to encapsulate radioactive liquid organic waste in geopolymer

•RLOW disposal by pre-impregnation and subsequent encapsulation in geopolymers is feasible.•Recycled polyurethane impregnant is incompatible with the geopolymer activator.•NOCHAR N910 polymer promisingly absorbs and stabilizes RLOW in a geopolymer.•Surfactants should be avoided as they would compromise stability towards water immersion. The pre-disposal management of Radioactive Liquid Organic Waste (RLOW) is hampered by its challenging physico-chemical properties. In this work, a straightforward conditioning option based on RLOW impregnation on absorbing materials and followed by encapsulation in a stable geopolymeric matrix is proposed, avoiding onerous pre-treatments and the use of surfactants. Recycled materials have been investigated as adsorbent and geopolymer precursors to foster process sustainability. Relevant properties have been studied to ascertain the waste acceptance criteria accomplishment: materials compatibility, RLOW loading factor and bleeding, microstructure, compressive strength, leaching and thermal stability. This approach is promising, although some criticalities remain unsolved. [Display omitted]