Simultaneous adsorption of Li(I) and Rb(I) by dual crown ethers modified magnetic ion imprinting polymers

Abstract

With the gradual exhaustion of land mineral resources, oceans and lakes have attracted world attention because they are abundant in inorganic mineral resources including lithium, potassium, rubidium and cesium. Lithium is becoming the key material in manufacturing of primary and secondary batteries used in various portable devices and hybrid/electric vehicles. Rubidium has been widely applied inglobal positioning satellites, magneto‐optic modulators, solid‐state lasers, phosphors, and glass manufacturing. In this work, a novel dual‐functional magnetic ion imprinting polymer (Fe3O4@SiO2@IIPs) powder was prepared using 12‐crown‐4 (12C4) and 18‐crown‐6 (18C6) as functional monomer, and characterized by FT‐IR, elemental analysis, XRD, TGA, SEM and TEM. The adsorption performance of Fe3O4@SiO2@IIPs for simultaneous adsorption of lithium and rubidium from simulative salt lakes was evaluated by batches of experiments at various pH values, contact time, and initial concentrations. Kinetic experiments show that the adsorption process followed the pseudo second order kinetic model. Langmuir adsorption isotherm model and Freundlich adsorption equilibrium data were fitted; the results show that Langmuir isotherm model is more suitable for the adsorption process. Additionally, Fe3O4@SiO2@IIPs exhibit specificity towards Li(I) and Rb(I) and low competitive behavior with Na(I), K(I) and Mg (II). Additionally, the selectivity properties, reusability and adsorption thermodynamic were also investigated. The obtained results show that the prepared Fe3O4@SiO2@IIPs material remains high adsorption capacities after five cycles, exhibits excellent abilities to simultaneously and selectively recover Li+ and Rb+ and have a promising application in the simultaneous adsorption of lithium and rubidium ions.

Technology for the Recovery of Lithium from Geothermal Brines

“…Selectivity Order Li + /Na Modifications of crown ether extractions include attaching crown ethers to carbon nanotubes, and combining crown ethers with ionic liquid extraction or supercritical fluid extraction (see below) [17,63,181,[185][186][187][188][189][190]. Several studies have investigated polymerized crown ethers for lithium extraction [191][192][193][194][195][196]. All of these approaches have shown some degree of success for selective extraction of lithium from simple solutions.…”

Crown-Ether Functionalized Graphene Oxide Membrane for Lithium Recovery from Water

“…Smaller rings such as the four and five membered ones have been proven to selectively bind with smaller cations such as lithium and sodium and reject the bigger ones through steric hindrance [20][21][22][23][24][25][26][27][28][29]. Works of dual crown ether functionalized to successfully recover two different cations at once have also be reported [30]. The family of 12-crown 4-ethers is known to be extremely selective toward lithium [31][32][33][34][35][36][37][38] due to the perfect fit of its cavity with the ionic radius of the lithium ion and is therefore used in this approach.…”

Fabrication of a novel magnetic rubidium ion-imprinted polymer for selective separation

“…Luo et al 11 developed magnetically imprinted polymer (Fe 3 O 4 @SiO 2 @IIP) with a core-shell structure using SIIT, in which 2-(allyloxy)methyl-12-crown-4 was adopted as the functional monomer. Xu et al 31 synthesized the bifunctional Fe 3 O 4 @SiO 2 @IIPs by simultaneously introducing the functional monomers 12C4 and 18C6 into the magnetic carrier. With adsorption capacities of 0.125 mg g À1 and 0.0946 mg g À1 , it showed good adsorption performance and stability in the 1 mg L À1 mixed solution (Li/Rb = 1), respectively.…”