Selective Capture of Ba2+, Ni2+ and Co2+ by a Robust Layered Metal Sulfide

133Ba, 63Ni and 60Co are hazardous to the ecosystem and human health. Their non-radioactive isotopes are also worthy of concern as toxic metal ions. Barium can be studied as a simulant of hazardous 226Ra because of their comparable ionic radii and similar ion exchange behaviors. Herein, we report that the layered metal sulfide (Me2NH2)1.33(Me3NH)0.67Sn3S7·1.25H2O (FJSM-SnS) exhibits excellent capture properties for Ba2+, Ni2+ and Co2+ with high capacities (qmBa = 289.0 mg/g; qmNi = 83.27 mg/g; qmCo = 51.98 mg/g), fast kinetics (within 5 min), wide pH durability, and outstanding Ba2+ selectivity. FJSM-SnS exhibits high removal efficien-cies (> 99%) for these ions in ion-exchange column experiments. The material possesses radiation-resistance with good structural and crystal stability; it survives highly acidic conditions. Our results point to a promising scavenger for Ba2+, Ni2+ and Co2+ and by extension the even more harmful 226Ra, and suggests that metal sulfide materials should be considered as effectiv...