Cold Sintering of Hierarchically Porous ETS-10 Zeotypes for Ion Exchange

Processes based on continuous ion exchange (CIX) and simulated moving bed (SMB) chromatography have shown potential for ion-selective separations, but practical application requires structured ion exchange materials. Here, we report the synthesis of Na-ETS-10 monoliths via cold sintering, incorporating sacrificial NaCl particles to introduce hierarchical porosity. Structural characterization by X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirms that the crystallographic integrity of Na-ETS-10, a microporous titanosilicate with potential for cation separation, is preserved after cold sintering. The inclusion of NaCl during cold sintering leads to microporosity after leaching the salt in an aqueous solution. N2 physisorption isotherms and SEM indicate the formation of macropores. Ion exchange experiments with Mg2+ indicate that while dense-phase monoliths exhibit lower uptake than Na-ETS-10 powder, likely due to diffusion limitations, hierarchical porosity enhances ion accessibility.