Readily regenerated porous fiber-supported metal tin sulfide for rapid and selective removal of cesium from wastewater

The removal of Cs from radioactive wastewater remains a great challenge due to the presence of a large number of coexisting ions. Herein, a novel porous fiber-supported metal tin sulfide named PVC-[Me2NH2]2Sn3S7 was designed. Specifically, four tin sulfides were prepared by the one-pot method in different solvents. Water was the most suitable solvent since it was essential for converting amides to cations. When three amides were used as precursors, [Me2NH2]2Sn3S7 prepared with DMF showed the best adsorption performance. Five polymers were then comprehensively evaluated around physicochemical stability, hydrophilicity, and cost to facilitate the engineering application of adsorbents. Finally, polyvinyl chloride (PVC) was selected as the support material. The optimized porous PVC-[Me2NH2]2Sn3S7 fiber with 50 wt% [Me2NH2]2Sn3S7 percentage can reach adsorption equilibrium within 30 min, has a wide active pH range of 2–12, and has a high adsorption capacity of 419.01 mg g−1. When applied to simulated wastewater, the separation coefficients of Cs+ and coexisting ions were above 1 × 104. The Cs + adsorption enthalpy change was obtained by calorimetric study and simulation calculation. Even after 50 consecutive cycles, the removal efficiency barely decayed. The Cs+ concentration could be enriched to 259.93 times that of the geothermal water. The above advantages make PVC-[Me2NH2]2Sn3S7 a promising adsorbent for selective Cs + removal from wastewater.