Open-framework hybrid zinc/tin selenide as an ultrafast adsorbent for Cs+, Ba2+, Co2+, and Ni2+

Efficient adsorption of radioactive Cs-137(+) and Co-60(2+) and their decay products Ba-137(2+) and Ni-60(2+) bears significance for hazard elimination in case of nuclear emergency, which relies on the adsorption rate enhancement that takes advantages of compositional and structural optimization. Herein, we report a zinc-doped selenidostannate constructed from T2-supertetrahedral clusters, namely K-3.4(CH3NH3)(0.45)(NH4)(0.15)Zn2Sn3Se10 center dot 3.4 H2O (ZnSnSe-1K). The soft Se and micro-porosity synergistically endow this material with a binding affinity to Cs+, Ba2+, Co2+, and Ni2+ ions and ultrafast kinetics with R > 97.6% in 2-60 min. In particular, ZnSnSe-1K can remove 99.34% of Cs+ in 2 min (K-d(Cs) > 1.5 x 105 mL g(-1)), contributing to a record rate constant k(2) of 9.240 g mg(-1) min(-1) that surpasses all metal chalcogenide adsorbents. ZnSnSe-1K exhibits good acid/base tolerance (pH = 0-12), and the adsorption capacities at neutral are 253.61 +/- 9.15, 108.94 +/- 25.32, 45.76 +/- 14.19 and 38.49 +/- 2.99 mg g 1 for Cs+, Ba2+, Co2+, and Ni2+, respectively. The adsorption performances resist well co-existing cations and anions, and the removal rates can keep above or close to 90% even in sea water. ZnSnSe-1K is employed in continuous column and membrane filtration, both of which shows excellent elimination efficiency (R > 99%) for mixed Cs+, Ba2+, Co2+, and Ni2+. Especially, the membrane with an ultrathin (70 mu m) ZnSnSe-1K layer can remove 97-100% Cs+ in suction filtration with a short contact time of 0.33 s. Combined with the simple synthesis, facile elution and great irradiation resistance, ZnSnSe-1K emerges as a selenide adsorbent candidate for use in environmental remediation especially that involving nuclear waste disposal.