Highly charged swelling micas of different charge densities: Synthesis, characterization, and selectivity for Sr and Ba

► Na-2-mica shows the highest selectivity for radioactive Sr2+ and Ba2+ among Na-micas. ► The (0 0 1) reflections of Na-micas shift with different extents of Sr and Ba uptake. ► Na-2-mica can remove Sr and Ba selectively from drinking and waste water or soils.