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Adsorption is an effective method to remove cesium and strontium from a solution. Although a variety of adsorbents has been reported, it is difficult to compare their adsorption properties due to different experimental conditions (such as solution concentration, volume, composition, temperature, etc.). In this paper, a series of adsorbents for the adsorption of cesium and strontium (ammonium phosphomolybdate, Prussian blue, sabite, clinoptilolite, titanium silicate) were synthesized and characterized using XRD, IR and SEM, and their adsorption performance in mixed solution (containing Li, Na, K, Cs, Ca, Sr and Mg ions, 1 mmol L−1), artificial seawater and salt lake brine were studied under the same conditions; in addition, the adsorption mechanism was elucidated. The results showed that ammonium phosphomolybdate has the largest adsorption capacity for cesium in the mixed solution. In artificial seawater and salt lake brine, Prussian blue displays the highest cesium adsorption capacity and the best selectivity. The multi-adsorption mechanisms are beneficial to the selective adsorption of Prussian blue in complex solutions. These results are useful for choosing adsorbents for cesium and strontium in applications. [ABSTRACT FROM AUTHOR]

A one-step hydrothermal method was used to synthesize a quaternary metal sulfide material, NMTS, to remove strontium ions from simulated radioactive wastewater, in which metal tin was replaced by tin and magnesium salts to reduce the cost of the raw materials. The adsorption characteristics and behavior of Sr2+ were studied using batch experiments. NMTS has a layered structure, and the approximate molar ratio of Na:Mg:Sn:S is 4:1:10:23, with an approximate 61% reduction in the raw material cost compared to NaTS. NMTS exhibited ultrafast kinetics for Sr2+ with rapid adsorption of 97.1% in 0.5 min and 99.8% at an equilibrium time of 3 min, followed by the pseudo-second-order model and Langmuir model with a maximum adsorption amount of 52.6 mg/g at 298 K. NMTS had a high affinity for Sr2+ with K d values of >106 at pH values ranging from 4 to 11. The adsorption of Sr2+ mainly involves ion exchange and surface adsorption. Ion exchange Na+ for Sr2+ was predominant with initial Sr2+ concentrations ranging from 5 to 20 mg/L, and both ion exchange and surface Sr S bonding interactions occurred with initial Sr2+ concentrations higher than 20 mg/L. Sodium and potassium ions had little effect on the adsorption of Sr2+, whereas the presence of calcium and magnesium ions greatly affected it. In addition, NMTS also exhibited high selectivity for the adsorption of cobalt, nickel, and manganese, followed by Ni2+ > Sr2+ > Mn2+ > Co2+. NMTS is a promising adsorbent for removing Sr ions from aqueous solutions. [Display omitted] • Na 4 MgSn 10 S 23 was synthesized by a one-step hydrothermal method using tin and magnesium salts. • Na 4 MgSn 10 S 23 exhibited ultrafast kinetics for Sr2+ with 99.8% at an equilibrium time of 3 min. • High removal of Sr2+ was achieved ≥99.2% was achieved over a wide pH range of 4–11. • The adsorption mechanisms include ion exchange and surface adsorption. [ABSTRACT FROM AUTHOR]