Direct 3D-printing of a Geopolymer-based Membrane Dedicated to Cesium Decontamination

Abstract

International audienceIn the context of the dismantling of industrial sites, the search for efficient and economically competitive solutions for the remediation of installations is a key objective to be achieved, in particular the depollution of industrial effluents containing polluting ions. Compared to other methods, solid / liquid extraction exhibits decisive advantages such as a possible selectivity of the targeted pollutant and the use the solid support as a pollutant containment matrix thus minimizing the volume of secondary wastes generated. In the literature, among many materials used as metal adsorbents (zeolites, apatites, ion exchange resins ), the use of geopolymer as exchange materials is also reported. The term geopolymer usually denotes alumino-silicate inorganic polymers synthesized at low temperature (typically less than 95 DC.) by alkaline activation of alumino-silicate materials. The material, which is initially fluid and has no yield stress, set and hardened gradually forming a monolithic material with an amorphous structure and a local order similar to zeolite. This work considers the fabrication and characterization of geopolymer-based architected membrane dedicated to the treatment of cesium-containing solutions. The key aspects of this study rely on the design of a viscoelastic material with requisite rheological characteristics for direct 3D-printing while controlling the microstructural properties and the ion-exchange properties of the geopolymer ink. This direct writing technic enables the control of the multiscale porous structure macroporosity can be designed by 3D direct printing while meso and microporosity are controlled by the chemical formulation of the geopolymer ink