Efficient Removal of Cs⁺ and Sr²⁺ Ions by Granulous (Me₂NH₂)_4/3(Me₃NH)_2/3Sn₃S₇·1.25H₂O/Polyacrylonitrile Composite

Abstract

The need to effectively and selectively remove radioactive 137Cs and 90Sr from nuclear waste solutions persists to mitigate their environmental mobility and high radiotoxicity. Because it is difficult to effectively remove them from acidic environments that degrade most sorbents, new sorbent materials are highly desirable. Here, efficient removal of Cs+ and Sr2+ is achieved by the composite of layered tin sulfide (Me2NH2)4/3(Me3NH)2/3Sn3S7·1.25H2O (FJSM-SnS) and polyacrylonitrile (PAN) (FJSM-SnS/PAN). The granulous composite possesses regular particle morphology and good mechanical strength as an engineered form. It shows excellent acid–base and γ-irradiation resistance, high maximum adsorption capacities (q m) of 296.12 and 62.88 mg/g for Cs+ and Sr2+ ions, respectively, and high selectivity even in the presence of excess Na+ ions or using lake water. Impressively, q m Cs of FJSM-SnS/PAN reaches 89.29 mg/g under even acidic conditions (pH = 2.5). The column loaded with FJSM-SnS/PAN granules exhibits high removal rates (R) toward low-concentration Cs+ and Sr2+ ions under both neutral and acidic conditions. Moreover, the composite can be recycled and reused with high R Cs and R Sr. This work highlights the great potential of metal sulfide ion-exchangers in engineered form for the efficient removal of Cs+ or Sr2+ ions, especially under acidic conditions, for radionuclide remediation.

Metal Sulfide Ion Exchangers: High Acid Stability of Na2xMg2y–xSn4–yS8 (NMS) and Topotactic Conversion to 2D Solid Acids with Semiconducting Character

“…Because their sequestration method relies on forming bonds between sulfur and the analytes of interest, they intrinsically have a low affinity for hard Lewis acid ions such as Na + , K + , Ca 2+ , and others. Previous studies have demonstrated high removal efficiencies of Hg 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , UO 2 2+ , Cs + , and Sr 2+ over a wide range of pH values (1 < pH < 12). − In particular, among the reported MSIEs, K 2 MnSn 2 S 6 (KMS-1) and KInSnS 4 (InSnS-1) have demonstrated selectivity in strongly acid solutions as well. These qualities make MSIEs promising candidates for use in the capture of actinides from aqueous solutions.…”

Highly Selective Separation of Cs+ from Brines Using an Electroactive Layered Composite of Vanadosilicate

“…Adsorption and ion exchange are generally used to remove trace ions from aqueous solution and exhibit an excellent application prospect due to its low energy consumption and environmental friendliness. In recent years, various Cs + adsorbents, such as metal sulfides, − ammonium molybdophosphates, metal ferrocyanides, − and titanate/vanadium/tungsten-based materials ,− have been developed. Among them, vanadosilicate composites, a series of porous materials composed of mixed crystal structures of silicon tetrahedron (SiO 4 ) and vanadium oxide polyhedron, such as vanadium tetrahedron (VO 4 ), pentahedron (VO 5 ), or octahedron (VO 6 ), have gained increasing attention.…”

“…Various technologies, such as solvent extraction, − chemical precipitation, and adsorption/ion exchange − have been used to separate Cs + from aqueous solution for decades. In these methods, solvent extraction is an efficient method for separation of Cs + from brine due to the high affinity between the extractants and Cs + ; however, extractants are generally expensive and easy to lose during extraction process, and the stripping may require strong acids.…”

Titanium Carbide‐Based Adsorbents for Removal of Heavy Metal Ions and Radionuclides: From Nanomaterials to 3D Architectures

“…[ 17 ] Microorganisms convert pollutants into safer substances through flocculation, adsorption, accumulation, and enrichment in the secondary water treatment. [ 18 ] In the tertiary water treatment process, the commonly used technologies are: ion exchange, [ 19 ] membrane method, [ 20 ] adsorption, [ 21 ] electrochemical deposition, [ 22 ] chemical oxidation, [ 23 ] photocatalysis, [ 24 ] and distillation. [ 25 ] These methods all have different strengths and weaknesses.…”