Layered A₂Sn₃S₇·1.25H₂O (A = Organic Cation) as Efficient Ion-Exchanger for Rare Earth Element Recovery

Abstract

Exploring new ion-exchangers for the recovery of rare earth elements (REEs) and recycling is worthwhile for the high-tech industry and an eco-friendly sustainable economy. The efficient enrichment of low concentration REE from complex aqueous solutions containing large excess of competitive ions is challenging. Here we present a chalcogenide example as a superior REE ion-exchanger efficiently removing them from very complex aqueous solutions, (MeNH)(MeNH) SnS·1.25HO (FJSM-SnS). The material exhibits fast and efficient ion exchange behavior with short equilibrium time (<5 min), high adsorption capacity (139 mg/g for Eu, 147 mg/g for Tb, 126 mg/g for Nd), wide pH resistance (1.9-8.5), the largest distribution coefficient (K) value of 6.5 × 10 mL/g, good selectivity against Al, Fe, and Na ions, and high recovery rate (>99%) at low concentrations. Moreover, after ion-exchange, the REE in corresponding exchanged products could be easily recovered by elution. FJSM-SnS has superior capacity and faster absorption kinetics than other states of the artificial REE sorbents such as AlO/EG, clay minerals, zeolite, and activated carbon.

Highly Selective Recovery of Lanthanides by Using a Layered Vanadate with Acid and Radiation Resistance

“…In the preparation of 1,t he dimethylammonium cations were in situ produced by the hydrolysis of DMF.S imilar phenomena have been commonly found in the syntheses of other ion exchange materials. [11,20] Without manual selection, the phase-pure crystals of 1 ( Figure 1a)w ere obtained as verified by PXRD ( Figure 1b). Then uclear wastewater treatments are usually conducted under acidic or alkaline conditions.T herefore,t he stability of 1 was investigated by soaking ground crystalline powdered samples of 1 in different solutions with various pH values for 12 hours.T he PXRD patterns of samples of 1 after above-mentioned treatments remain almost unchanged (Figure 1b), indicating an excellent stability of 1 in wide pH range from 1.9 to 12.3.…”

“…[21] [Me 2 NH 2 ] + as charge compensating cations are located at the interspaces of layers. Thel ayered structure,e xchangeability of interlayered [Me 2 NH 2 ] + cations, [11,20,22] excellent pH stability,a nd easy preparation provide the prerequisites of 1 for the adsorption of Ln ions.Eu 3+ and Sm 3+ ions adsorption experiments were carried out, respectively,and the corresponding Ln 3+ -adsorption products were denoted as 1-Eu and 1-Sm, respectively. EDS confirms that Eu 3+ and Sm 3+ ions have entered the structures of material (Supporting Information, Figures S2 and S3), and elemental distribution studies show that Eu 3+ and Sm 3+ ions were uniformly distributed throughout the samples (Supporting Information, Figure S4a).…”

“…[5c, 6] Methods utilized to capture or separate lanthanides include solvent extraction, [7] chemical precipitation, [8] liquid membrane separation, [9] biological treatment, [10] adsorption, [3b] and ion exchange. [11] Thes olvent extraction as the common method generally uses toxic volatile organic solvents that may cause second pollution and third phase formation. [7] By contrast, the adsorption and ion exchange are quite promising owing to easily operation, low cost, little second pollution, and effective reduction of the volume of solid wastes.…”

“…[7] By contrast, the adsorption and ion exchange are quite promising owing to easily operation, low cost, little second pollution, and effective reduction of the volume of solid wastes. [11,12] Tr aditional inorganic adsorbents,s uch as zeolite, [13] graphene oxide (GO), [14] and heteropoly acid salts [15] have been deeply investigated;h owever, the disadvantages such as poor selectivity,n arrow pH range and inability to separate lanthanides from multi-ion mixed solutions stunt their further applications. [11] Thus,i tis important to develop new absorbent materials for the recovery of lanthanides from radioactive wastes.…”

Discrete Supertetrahedral T5 Selenide Clusters and Their Se/S Solid Solutions: Ionic‐Liquid‐Assisted Precursor Route Syntheses and Photocatalytic Properties

“…Crystalline metal chalcogenides have been extensively studied as potentialm aterials for use in thermoelectric [1] and optoelectronic devices, [2] photocatalysis, [3] as well as other applications. [4] Metal chalcogenidesc onstructed from supertetrahedral clusters (typicallyT n,P n,a nd Cn)h ave been well documented for their diverse cluster type, size, and outstanding proper-ties. [5][6][7][8] Among them, Tn cluster-based metal chalcogenides are particularly attractive because their regulart etrahedral arrangements can be regarded as fragments of zinc blende type lattices.…”